Understanding marine diesel engines: Yanmar coolant exchange
Vložit
- čas přidán 7. 05. 2020
- This video is a detailed demonstration of the fresh water cooling system of a salt water Yanmar diesel marine engine, including a description of repair principles and anticorrosion features to control galvanic reactions. The engine shown is a Yanmar 3GMFC engine with the SB20 sail drive. I show details of how to drain and refill/replace the antifreeze/coolant, and describe the layout of engine zincs present in some models.
This is an amateur presentation offered for free and in good faith, but with no guarantees as to accuracy or safety. Engine repair comes with inherent risks. Any misadventure you encounter if you decide to accept the risk of DIY repair is your responsibility.
Music clip at the end is by River Meditation by Audionautix, licensed under a Creative Commons Attribution license (creativecommons.org/licenses/...) Artist: audionautix.com/ - Auta a dopravní prostředky
Hi I was in Vancouver for 30 years from 1975 to 2005 I worked the distributors for Volvo Penta and Yanmar. Parts and Service and Warranties. I flew a desk and spare time rebuilt pumps and injectors. We use to run local service school on a weekends for our customers. Enjoyed the work and the companies were good to me. I enjoyed your explanations and service tips. Excellent and good job. Clean boat and well kept. Thanks for this video. I enjoyed it.
I’d love a teaching service school
Thank you so much! 🙏 This video taught me so much more than the original manual did. I think you indirectly saved my 30 yo 3GM30F and potentially much more!
Thank you for the excellent series of videos about these systems. Very clear and well filmed!
This explains a number of things that have taken me years to understand by trial and error. Keep posting !
These marine engine vids you have created are fantastic & so well appreciated as I move into dealing with a Yanmar 4JH
I purchased a used Hunter V32 last fall, with a Yanmar 3GM30F that is original to the boat. Your videos are extremely helpful in shallowing the learning curve!
Thank you so much, this gave me the confidence to change coolant myself yesterday after watching the video several times. It was successful thanks to you!
Thanks for sharing! This is all new to us. I can't wait until we can do these things without any stress. Cheers
Nigel Calder's books on boat systems and maintenance are a great source, but your videos digest the same topics in such a nice format. I hope to see more videos in the future.
I am about to pull my very tired and underpowered SB8 for a solid running 2gm20f and this video definitely helped me understand the cooling systems and make me far less nervous. Thanks so much from a fellow Vancouverite 😊
Thanks for this video. I had a Yanmar raw water cooled engine, so zincs were important and there was no heat exchanger. Now I am looking at a used boat with a fresh water cooled block and the associated heat exchanger. This video was a help in anticipating the differences,
Thank you so much ! I have the same engine and your videos have really helped me get a better understanding of this type of system. I replaced the coolant, oil, oil filters and fuel filters based on your videos without any issues. However, most importantly, I am able to troubleshoot easier knowing how the whole system works. You are a good teacher ! Hope you continue to make videos like this.
Great Video, excellent camera work and commentary, goes in-depth and covers crucial items glossed over by others.
Thanks for the instruction and video. We've got 2 Yanmar 3YM30AE engines in our catamaran and I'm watching everything I can find on Yanmar marine maintenance. Thanks.
excellent descriptions. And the pauses to ask questions really makes me think and reinforces my understanding of what you are teaching me. Keep up the good works!
Thanks, man!
Absolutely fantastic tutorial. Thanks for your efforts and editing and explanations
As always, most informative and a pleasure to watch. Thanks for posting! :-)
I think I understand my cooling system for the first time! Thanks!
Great video. You've got a great relaxed manner and you make sure that you don't use jargon or expect too much knowledge. I've read a fair bit about my Yanmar but you've given me a lot of valuable information I've missed. Many thanks.
Very well explained video Dave! Another reason for good maintenance on marine cooling systems is that it's all uphill for a boat engine. It never gets to just coast along.
Take care and thanks,
Bill
This was very helpful. I"m rebuilding my 3HMF and at the end of connecting the hoses back but had no idea which is for what. I tried to follow the service manual and the parts manual for a while and just scratched my head. I watched your video and it was really to the point and perfectly explained. I went ahead and labeled all the hoses and what they are for. Thank you for making this video.
These are great - thanks so much for your time and effort with these.
Very well done, complete and accurate.
This is great info. I just bought a boat that is set up the same. My first month of ownership saw a $1,800 maintenance bill for cleaning sludge from lack of proper preventative maintenance in the fresh water coolant side of my Yanmar. I won’t let that happen thanks to you
Thankyou, you have probably saved me and many others considerable time and money.
That's for sure!
Awsome basic and technical discussion. I especially like the discussion about the engine zincs and their purpose. There is much confusion in the sail community on the need or no need to replace these internal zincs.
Great video - informative, clear and concise and well made. Thanks.
Picked up a great tip on “the feel” test of the inlet and outlet pipes to/from the heat exchanger to confirm that the thermostat has opened. Thanks
Definitely easier to do on land than out at sea. Good info, thanks Dave.
Great informative video. In most videos you have to fast forward to the actually useful information, but in your the info comes fast and furious so I have play it on slow speed to get everything’s. Thanks 😀
Great video, you are obviously knowledgeable and experienced. Thank you for putting together these instructional videos. I found your initial review tracing the raw and fresh water side passages through the engine helpful. It’s also great when you actually explain the various pieces we are looking at. For example I came across exactly the same two valve thermostat diagram in one of Nigel Calder’s books, but could not really “visualize” what was happening until you EXPLAINED the diagram. There is NOTHING I can say to improve your video-outstanding really and thank you again!
What a kind remark, thank you, you made my day.
Great video, thanks! On my yanmar, the overflow tank can easily slide up and off once you remove the cap, and you can empty it in the sink as well as rinse it out.
Great Video Dave!
Hi Dave, your vid really helped me out. Thanks a lot from Germany
Excellent video! Thank you
I have had some mystery coolant leaking into the bilges over the last few weeks - definitely going to check that weep hole next trip to boat - thanks for the pointer.
Another great video.
This video helped me tremendously!
Fantastic video and wonderfully helpful for a novice like me! Wonderful audio and terrific descriptions so many many thanks - David
Thanks, man!
Dave
Thank you so much for this very well explained and made video
Love your videos! You've saved me loads of money and time!!! I'd like to request a quick video on changing the zinc anode please, or maybe tag it on with another tutorial. Thanks!
Great video, thanks for sharing that with us. I am trying to learn more about the coolant system to diagnose a coolant leak.
You're welcome. I have done a series of automotive cooling system videos on my channel, assembled in a playlist that you may find helpful. I did a few occult coolant leak videos that will apply to marine engines as well. On the marine side I did a few videos on the salt water pump, the fresh water pump, and the overview shown here. Some auto parts stores will lend out a coolant leak tester that you may find helpful. Most leaks will only occur when under pressure, and it is dangerous to work around a roaring engine.
Thanks very much for the vid, learned a lot of it!.
Very well done, bravo my friend your friends from Fort Lauderdale Florida USA
Thanks for following along, Angela.
Great video! Thank you !
A well explained video and i learned even more from the comments, time to apply these things now, fair winds !
Thanks, my reply to Patrick smith summarizes it well. Fill both the reservoir and at the cap, since both need to be close to full for the automatic burping process to work. Happy sailing! Sailboat racing is canceled around here because of Covid protocols, but we hope to resume in a couple of months.
@@spelunkerd Hi there, I decided finally to do the coolant exchange job, from what I can see there is some solid sediments in there mud like stuff.
How do you flush the system from this ? I remember at the video you wanted to do this job sometime.
@@boardelia I did a followup two-part video where I change out the coolant water pump. I think part 1 was titled something like "how to clean a marine heat exchanger". At the beginning of that I show a short clip where I removed the starboard side coolant drain petcock, then take a loop of wire and push it up the hole to allow coolant to sweep that debris out. It's a messy job! Once the heat exchanger is removed you can clean it well. Cleaning that heat exchange is a normal maintenance job you should do every several years. Good luck!
@@spelunkerd I just wached it, thanks for the time you took to write to me ;)
You make things look easy, i hope it will be the same when i do it !
Oh by the way, i hope you didn't skip the lub oil cooler, it has the same tube structure as the heat exchanger and needs the same treatment - at least as the yanmar 4jh2 series i have.
very good video!
I've been a dinghy sailor my whole life, but I finally decided to buy my first big boat earlier this summer. I got in way over my head trying to understand and take care of the engine, but as a visual learner, your videos have been a godsend to get me up to speed on the basics. Thanks!
We're in the same boat buddy! How are you getting through?
@@sailboatshellesseasailing4567 we've made it this far without any catastrophes! Every little thing I've done on the engine, even if it's just as simple as changing a filter or something, adds to the bag of experience
@@jackdodsworth6077 Good Work! I'm hoping for the same luck! This week I'm I'm going to take some tape and label the parts so I can get more familiar with them
@@sailboatshellesseasailing4567 what make of boat did you get? I was looking at first for a little 23-25 footer bc that was a little more in my price range, but I wound up getting a 30ft S2 9.2 from a very nice older couple who just wanted to pass the torch rather than recoup money, so they sold it to me for 60% of what it was worth. Very serendipitous, it's been an absolute joy for the last year
@@jackdodsworth6077 You're a winner! Haha that's great. I managed to get a 1998 Beneteau 30 (somehow it was made after the production of that boat generally stopped). I got it from another sailor who already moved up in size some years ago and still had this one in the marina but conveniently was trying to sell just as I was finishing up uni.
Thank you….I’m learning bit by bit on my 6LPA SPT2 on my Fortier 26….
another great video
Thank you for showing the blocked drain. When I drained my coolant, nothing came out. I remembered your video on blocked drain and i used a galvanise wire to poke the valve, lots of dirt flowed out with the coolant. :)
Yeah, I'm planning on doing that when I get a chance, it will be a messy challenge if successful. If I can clear it that way, there is less need to remove the housing, though I have new gaskets already. This drain is obviously designed to be in a place prone to sedimentation, and draining regularly will help to keep the system clear.
I had a semi blocked drain on my port side as well. And coz I saw your video I unscrewed the spigot and plenty of sluggish sediment came out. I flushed the system twice to get (hopefully) rid of the sediment. But will do coolant change now more often.
Two questions if you don't mind asking:
a) what exactly is that sediment? How does it evolve? (FYI: In my case, I had a leaking seal on my heat exchanger and so coolant and sea water were mixing each other. But I hoped I had it fixed with a new seal).
b) Many different opinions about using expensive coolant from a marine dealer versus cheap coolant from the car part store/gas station. Manual says to use coolant code 7997, 7998 or 7994. If you could on one of your next videos talk about the importance (or not) of using the expensive coolant.
@@tobibcngmail8042 I think most of that debris comes from hard metals dissolved in normal water when people incorrectly use tap water to dilute antifreeze. There is likely some oxidation and rust as well from the sidewall of the tank. Antioxidants in coolant are designed to control that. The first generation of inorganic silicates and phosphates have largely been replaced by more modern antioxidants, and the newest have an "OAT" organic chemistry that doesn't last as long. Honestly I almost always try to replace it with what went in before, if I know. Failing that I put in what the manufacturer recommends. There is a popular and inexpensive 'universal' coolant that would be a reasonable choice. Thanks for watching!
@@spelunkerd thanks for your response. Keep on doing such explanatory videos. (e.g. would have loved a video for heat exchanger cleaning).
Another good video. Ant.
New friend, watching from Manila, Philippines👍👍👍🇵🇭
Hey man, thanks for dropping by, from Victoria, Canada.
Thanks so much for this video. I fou d it extremely helpful. I just bought a 30 foot Beneteau with a similar engine. Although I've been sailing all my life, I am new to the e gone aspect of things. (I have a lot of work to do on the engine. Thankssss)
great info, thank you!!
Very good
A cautionary tale. My heat exchanger drain was completely plugged as well. I removed the small housing held in place by 4 bolts; it had 1/2" of gunk in it plugging the drain. Coolant gushed out when it was removed but what I did not realize at the time was that my dipstick was dislodged. After flushing the heat exchanger with generous amounts of fresh water, I put everything back together, filled with coolant and ran her up. Well, it was not long before the dipstick blew out and grey coolant sprayed everywhere. I quickly shut her down and then began the long tedious job of removing all the contaminated oil. Several flushes and oil filter replacements later, the oil looks relatively clean. The moral of the story: be very careful running water or coolant around the dipstick hole! Thanks for the tip about the plugged drain hole.
Thanks, Mike! It is sound advice. I've been procrastinating that job, I have the gaskets to take it all off if I need to. I think I'll try to get by with poking something up there, and I'll think of your experience when I do it. If that doesn't work then I'll take the whole thing off and clean it on the bench.
Dave
@@spelunkerd Hopefully, you can get by with poking a wire up there. In my case, the crud was 1/2" thick and had the consistency of clay. I'm glad I got it out but I will be very careful from now on. I think the oil is clean enough for an extended run up now, will try soon. Thanks very much for all your videos, really well done.
Mike, Lovely Cruise, C&Cii, St Margarets Bay, N.S.
I had my boat out today and had a coolant line crack that exposed itself. I am not sure why the 3HM35F got so hot. I love the diagram cutaways.
Love this thank you
Just bought an old Tanzer 28 with this motor, I used to live were you are but now Im on the Sunshine Coast.
your videos are great, nicely done and very thorough. If you ever need a cameraman to trade for some diagnostics on my yanmar let me know. hope to run into on the water this year as my Mom is buried in Nanaimo and my first trip will be over there to protection island. thanks
Best regards,
Shayne
Hi Shayne, it is nice to meet you.
Dave
Hello from Connecticut
Muy buena explicación, podrías decirme si se puede limpiar los enfriadores con Sadira para ni tener que desmontar todo,tengo 2 yanmar 4 lh-hte
Sorry for the stutter step on the upload for this one, friends. I used Photoshop on a different computer to modify a diagram at 5:22, and when I transferred the file back to FCPX I ignored that pesky message saying I should ask for permission before removing the USB stick, ha ha. It looked OK until I compressed the video to send in, at which point a blank screen was recorded for a minute. I didn't notice until I saw the defect on CZcams. This one should be OK.
It's still wet and rainy in Vancouver BC. May 14.
Thanks for all your videos! They’re concise, well planned out, and highly educational. I especially liked that one you did about troubleshooting fuel gauge senders. I have to change out the fresh water pump in a Yanmar 2GM20F soon, I’m a little worried about getting an air pocket when I put the coolant back in. Any tips? Cheers!
These little engines are pretty easy to burp. Run the engine while tied to the dock with heat exchanger cap off for a while, keep adding coolant until you feel the tubing warm up, suggesting the thermostat has opened. Then shut the engine down, put the cap on, top up the reservoir, and recheck in the morning. Keep topping up that reservoir daily, and when cool remove the cap to verify that the level in the heat exchanger is full. If it doesn't seem to be burping, check the cap again for small cracks and pinhole leaks. Caps and tubing are cheap and easy to replace. Good luck!
Hi Dave
Great video thanks
I just had a saildrive block with an eel !
Emptied out water coolant and blew a hole in muffler.
I need to refill fresh water, and replace muffler.
Any tips of other things to look for would be appreciated
Pete (UK)
I just came across your most informative video while looking to solve a recent problem with my Yanmar 27 HP engine on a recently purchased Hunter Legend 35.5 sailboat.
Yesterday I ran the engine for about an hour, thinking my seacock for the engine seawater cooling system was open. After figuring out that the shrill tone I heard was an over temperature alarm, I shut down the engine. Upon inspection, there was a pool of coolant under the engine and some smoke and sizzling sounds. The coolant reservoir was empty.
Being new to this, I thought that refilling the reservoir might be enough to correct the problem once things cooled down. Wrong.
Today I found that the heat exchanger had no visible coolant in it, so I refilled it with a half and half mixture of marine diesel anti-freeze and water. I ran the engine for a couple of minutes, then re-checked the coolant level. Both the heat exchanger and the reservoir were still full. I resumed running the engine only two be alerted to an over temperature condition again after about 15 minutes. I shut off the engine and had another look only to find more spilled coolant and no visible coolant remaining in the heat exchanger. The reservoir remains full. Both hoses going into and out of the heat exchanger were hot the touch.
I’m trying to decide what I should do next and thought I would reach out to you and the community for any suggestions.
Minor correction: it’s actually a 24 horse power, model number 3GM30F Yanmar Diesel engine.
Also, that one way anti-siphoning valve you mentioned in the beginning of your video seemed to be stuck. Sure would not flow in either direction. I disassembled and reassembled it and the air now flows in one direction.
Might just provide enough of a correction for the heat exchanger to function properly again?
I thought it might be worth trying it again since one thing was seemingly corrected. This time I observed what was happening while it was running and after a few minutes there was some coolant dripping down on the port side of the engine block. Following the wetness upwards lead to a heat exchanger intake hose which may have been damaged from the previous day’s overheating episode. I suppose that once enough coolant leaks out of the system that overheating would be the natural result again. Once I remove the hose I may be able to confirm that it has been damaged, otherwise perhaps there is a stuck valve forcing a leak at that junction point.
Gee, this is serious. Unless you're confident in your abilities, it might be time to ask for help from a pro. Running for that long can pooch the whole engine, and you don't want to feel you didn't do everything possible to prevent that. As you say, overheating can cause secondary head gasket issues, hose problems, even water pump problems. If I were tackling this problem, I'd start with the salt water side, to verify that indeed the salt water pump is pushing salt water through the heat exchanger and that ample flow is coming out the tail pipe. If not, I'd disassemble the salt water pump and check the belt and the impeller, since those rubber things commonly go bad after a few years. If a vane of the pump impeller is broken off it can float downstream until it gets stuck leading into the heat exchanger. If nothing is coming out the tail pipe you can disconnect various hoses leading back to see if good flow is possible out the pump. Even something as simple as a plastic bag sucked into the salt water intake or a bad sea cock can be catastrophic. While the belt is off I'd spin all the pulleys to be sure none of those bearings have seized. Also check the seal at the filter because a loose cap can break the siphon and prevent adequate flow of salt water. If everything is OK on the salt water side, I'd run the engine for a while with rad cap off, filling with distilled water as needed to keep it topped up, and watch what happens. If it quickly overheats, especially if you get a lot of air bubbles at that time, you're in trouble. It could be as simple as a sticking thermostat, trapped air, a bad heat exchanger cap, or as serious as a head gasket problem. Feel the outlet hose from the thermostat to decide whether it opened. If the head gasket has leaked coolant to a cylinder, you can verify that with a little test that identifies combustion products in the cooling system. Hopefully not. Good luck!
@@spelunkerd Thank you for all your great suggestions. The seawater side of the system was working well. I was able to confirm a damaged 5/8” coolant hose was leaking coolant near the attachment point on the intake side of the heat exchanger. Whenever the engine ran for more than a few minutes coolant would begin to leak from there. I managed to cut off the damaged piece and reattach the hose after careful rerouting to compensate for the reduced length. The engine now runs great with no leaks and no overheating.
@@goob_7499 Oh I'm so happy for you! Keep a close eye on the system, over the next few weeks. If it isn't quite right, you might consider swapping out the thermostat, and maybe even swap the heat exchanger cap. Occasionally if the thermostat is intermittently sticking, pressure in the system can rise above a safe level and hoses can fail as a result of that. The cap on the heat exchanger is designed to open if pressures rise too high, but that cap can stick. Also if that cap sticks open you don't get the higher pressure the system relies on to raise boiling point. Thermostats and heat exchanger caps are relatively cheap and diagnosis can be tricky, so if there is suspicion either is bad it might be wise to replace them. Thanks for letting us all know how this was resolved! These kind of remarks make the discussion thread worth reading.
I have read many times to never switch from green to red coolant (or visa versa) the issue is that if you don't get every last drop out of the system of the other colour, the 2 colours mixing create a very acidic solution which destroys radiators/heat exchangers. Always stick to using whatever was in there from the factory or the previous owner (or look in the manufacturers service guide)
Thank you for your input. I mostly agree, as evidenced by the entire shelf of different antifreeze solutions at my shop. Each is dedicated to a member of our small fleet of vehicles. In the case of Yanmar, they don’t specify what brand of antifreeze to use except to say they recommend one with anti-corrosion properties and one that plays nice with aluminum. Finding an exact match to the old coolant would be impossible, although it it was almost certainly ethylene glycol, probably with old style silicate or phosphate IAT inhibitors that don’t last very long. The coolant I chose is ethylene glycol based, with no silicates or phosphates, and the data sheet indicates broad compatibility and hybrid chemistry. In any case I am planning on servicing the heat exchanger next month, so another flush is planned anyway.
@@spelunkerd I have heard the same thing. If colors have been changed in the past, that might be why your heat exchange drain plug gummed up.
@@flipitygibet That's a thoughtful point, though typically green coolant is used in perpetuity, and the popular 'universal coolant' wouldn't do that. More commonly people used tap water to dilute coolant, and impurities in tap water were by far the most common cause of precipitates. I haven't used tap water in years, but even today I saw a pro pour tap water into a classic car. Not wise or responsible, but the cheat saved him a couple bucks and the client will never know. Stop leak is the other mistake, though it typically has a mucky texture, very different to this. Of course the other issue is rust, made worse by expiration of antioxidant inhibitors. Old style green coolant has inhibitors that don't last long and don't work very well, and many versions don't play nice with aluminum, although the base antifreeze lasts forever. This did have a rusty color.
Thank you for the informative video! I recently went from a Westerbeke to a Yanmar and now getting familiar with the 3gm30f3. You mentioned a heat exchanger flush, did you ever get after it?
Dang, I've been procrastinating, but I did locate and buy all the seals from the dealer, including the exhaust manifold gasket. I've been thinking I'll remove that spigot and put a wire up inside, try to get fluid moving, and then clean up the mess. If I can get fluid moving, I can skip removing the housing completely and do regular cleaning of the heat exchanger in the usual way. Interest in recording waxes and wanes, I'm hoping to record it if I can build up the passion to do so. It is nice to meet you!
Great video! Thank you for investing the time to share your knowledge! I have a 2GM20F and am about to replace the five original freshwater cooling hoses. Today I drained the coolant and flushed several times with fresh water. Tomorrow I'll pull the hoses and replace with Yanmar parts. One question though, about the short (2") hose connecting the fresh water pump to the heat exchanger (shown in your video). It seems to be too short to get off without removing the thermostat housing, and it looks like there's a gasket under there which I might not be able to get on short order here. Am I missing something, or must I remove that housing to replace that hose? Any thoughts on reusing the original gasket? Also, what are your thoughts on using gasket grease? Thanks in advance!
When putting hoses on for various purposes I routinely use a small smear of silicone paste, if only to make the task easier. The brand I use is made by 3M 08946, but there are cheaper alternatives like Sil Glyde. It helps you slide hoses on much more easily. Silicone paste has multiple uses, and it has a very high breakdown temperature which makes it good for other things like brake caliper sliders, etc. It never hardens, unlike RTV which is designed to harden (don't use RTV on hoses). Getting old hoses off can be a chore. I use a large pick with a 90 degree bend, slipping it between the hose and the steel nipple to break corrosion all the way around and loosen it up. The other option is to carefully cut off the old hose, which is a time saving trick routinely used by shops that do it all the time. Don't gouge the underlying steel. Some plastic hoses (like a bilge pump hose) can slide on a little easier with a small amount of heat, but coolant hoses are designed to withstand heat so I wouldn't bother with that. I'm not sure if I ever replaced that short hose at the top, but I definitely replaced the two more prominent hoses in the front. Neither had a gasket, and both went on easily. As you say, if you're replacing a short hose it may be wise to have a plan B, which may involve needing an extra gasket for the next flange. There is controversy regarding RTV and gaskets. I try not to use RTV but if the gasket leaks I don't hesitate to use a light smear of RTV on a gasket. By the way, I would do a final flush with distilled water before you add your coolant, since tap water can have calcium and phosphate ions that may crystalize out of solution and mess up seals and your heat exchanger passages.
Hello Dave, excellent video. Just one question when refilling the pipes from the potable hot water cylinder. Do you leave the pipes connected at the hot water cylinder end and one connected at the engine end and then refill via the remain disconnected engine end pipe and at the same time holding it higher than the other pipes highest point and fill using a funnel until full ? Once the line is full I assume you then put your thumb over the end and quickly connect to the engine ? . Hope this question makes sense.
It depends on whether you want to flush the old coolant out of the heat exchanger. I didn't bother to do it, but if I wanted to I would have siphoned distilled water in one end while putting the other end as low as possible into a large bucket. When clear, stop and reattach both ends, refilling as much as practical. You'll get less trapped air by doing it the way you propose, but in any case trapped air will be flushed out by natural coolant flow the next time the engine is run. Trapped air is eventually cleared over several heat/cool cycles by the automatic burping process, if your cap seal is good and reservoir tubing is intact. Nice to meet you!
Very helpful. How do you ensure that new coolant gets into the engine block part of the circuit when the engine is cold as the thermostat would have closed off the flow through the heat exchanger? Also what is the normal replacement period?
Great questions. I answer those in a playlist of cooling system videos on my channel. The jargon term is 'burping' the cooling system, which in some engines can be difficult, but in these little things it doesn't take much. As a usual plan after changing the fluid I carefully start and run the engine with radiator cap off. I patiently stand there and add coolant to keep the level up. Then I wait til the hose leading to the heat exchanger begins to warm up, showing that the thermostat has opened. You'll notice a swirling of the fluid showing that has happened, and you may see bubbles coming to the surface, as the pump pushes fluid with air pockets to the top. The usual replacement period is a few years, more important with new style coolants that have antioxidant chemicals to prevent corrosion.
Thanks excellent presentation. As I'm getting ready to change my cooling fluids - I'd like to flush the system to remove dirt, rust or any other particulates - is there a recommended flushing solution?
In the old days we'd flush the system with a garden hose, letting coolant get into storm drains! Not appropriate today. I would flush with water, preferably filtered or distilled, and I'd find a way to trap the outgoing water into containers to be recycled. Then I'd do a final flush with distilled water. As you know there are acid-based cleaning compounds that can clear calcified debris more effectively, but these are less popular now that aluminum components are so prevalent. Unless you have clear evidence of calcium buildup I think I'd avoid heavy cleaners. Over our generation we have mostly given up using tap water for the cooling system, favoring premixed coolant or diluting with distilled water. So the need for heavy decalcification of the fresh water side is less than it was. For the salt water side, weak acids like acetic acid and phosphoric acid (barnacle buster) are popular but you want to avoid letting them spill freely into the ocean. Good luck!
Fantastic video, which i’m using today in sunny Greece. At one point you say something like “I’ll need to do a video on flushing/cleaning the coolant circuit” because you had clogged drains. I do too. I looked at all your videos, but couldn’t find one. Spent hours on boats forums, looking at this subject, specifically what (if any) chemicals to use. VERY strong opinions against common flushing acids. Even diluted vinegar had a few detractors. So if you time for this, i’n really appreciate it. Maybe add a link from this one? Keep up the great work 😍
PS: recently flushed the raw water circuit, circulating a product from/to a bucket around the circuit, using a tiny pump and two hoses from the engine. Could something like that work?
I've been procrastinating, ha ha. Reading chatter on the 'net, a popular agent is Barnacle Buster, which is phosphoric acid, said to be relatively nontoxic. Low pH acids work better but are more dangerous if handled incorrectly, and there is some risk of damage to underlying structural components if you leave it in contact for too long. I believe most of that can be negated by proper dilution but even dilution of a low pH acid can be risky if it splashes around. You can get better results by pulling the heat exchanger apart and doing it separately, and that way there is less risk to organisms living in the nearby waterway. That was my plan, I have the seals and am just waiting for motivation. Sure, your hose idea with a closed system would work fine, trapping the waste to dispose of safely. About a month after doing this video I made a loop of wire and removed the spigot for the cylinder drain. I put a pan underneath, then pushed the loop of wire up that hole. After a splash of coolant the debris was cleared and it drained briskly. I flushed it with some distilled water and then refilled the coolant system. It would have been a lame video by itself so I didn't record it.
hello, very good video thanks. i have a question: i need to replace the coolant in my yanmar 4jh4ae i have water heater exchanger connected, you skipped that point in the video, how do i empty the pipes and refill them in order not to get air trapped? thank you very much for your help!
Excellent question. The right way to do it would be to disconnect both hoses leading to the heat exchanger, then flush the lines from one end. If you had a drain petcock at the exchanger it would be easier but many don't have one, and draining at the exchanger is difficult because of space considerations. I would flush with distilled water from a jug, using a funnel into one hose and a bucket draining the other. The fill line has to be above the high point of the drain loop for the siphon to work. To get most out you'd have to replace volume twice, probably a couple of liters. Then when clear, flush with coolant. The simpler option would be to disconnect and fill only one line, draining extra volume sent to the engine the normal way from the engine. Inevitably you'll have trapped air at the top of the hoses after reconnecting. Your water pump will automatically clear that trapped air, by pushing those air bubbles into the heat exchanger after the engine warms up. When hot the expanded high pressure air is pushed past the valve in the rad cap into the coolant reservoir, where it percolates to atmosphere. As engine cools, fluid in the coolant reservoir is drawn back to replace the volume lost.
Great video! I don't think you mentioned flushing the old coolant out.. mine is rusty, can I just use hose water for flushing or must it be distilled
Even today, I'll guess that many professional shops use unfiltered water, to save themselves money, over their clients' interest. It's ethically very important to reclaim and recycle all that fluid, even the water you use to flush it out. So, it becomes a practical consideration of how many empty containers you have available to fill. With few containers you are probably better to use distilled water from the outset. Walmart sell inexpensive distilled water in their food section. If your engine block and head are steel, you can buy cleaning agents that have the same chemistry as CLR. You pour it in, fill the system up with water, run the engine for a few minutes, and drain. I believe the risk of damage from a cleaner would be significantly higher with an aluminum block. In the old days I remember using a T to a garden hose, running the engine with the hose flowing, and letting all that drain onto the pavement. We wouldn't think of doing that today.
Thank you for your video, I am in Vancouver as well. I tried to open this cap and no success. any recommendations?
Place your palm on the top and press down, then rotate CCW a quarter turn when cold. They are spring loaded. I'm in Victoria RVYC in Cadboro bay, Equinox, nice to meet you.
Thanks for the video, it is super helpful! 3 questions if you have time:
1) When you drained the coolant why didn't it also drain the loop going to the water heater?
2) How on earth do you detach one of those water-heater-loop hoses without making an enormouse mess (and I also can't imagine how you refill them without an equal mess)
3) I assume you "check" for air by making sure you replace the same amount of coolant that you took out. If you take out 8L, but only 7L "fit" back in... how do you get the air out? Is there a bleed screw like on a fuel line?
Excellent questions. It would be easy enough to detach one side, have a bucket of coolant/distilled water above and flush it through. If only one side is detached then it will return into the engine and drain through the usual engine drain. Messy if you detach both, but you won't risk sending debris deeper into the engine. The only way to get solids out would be to remove hoses at the heater and flush there. Regarding air, the burping process is to leave the cap off, run the engine, and let the pump push bubbles to the top where they clear. As you say some engines have bleed lines, this one doesn't. Auto technicians sometimes use a vacuum system to more quickly release air. If you get it close, the auto-burping process at the cap takes care of the rest. Thanks!
Oh, forgot #1. The heater is so low that when air breaks the siphon the remainder will stay in the heater core.
You mention the pin hole leak in the overflow tube. I recently took a boat out that I found later had the recovery tank cap off, and engine compartment was spewing white/grey smoke. Is it possible the pressure blew off the cap? Or is it more likely it wasn’t secured properly and coolant was being leaked all over the engine block. Great vid.
Hard to say, a severe overheat will cause fluid to spew back and it could blow the cap off. As you say, when coolant hits the top of a hot engine, it will create steam. On the other hand with a boat, if cap is left off it wouldn't be uncommon to spill coolant everywhere. When you refill, be sure you also refill from the engine cap, not just the recovery bottle. Trapped air can cause an overheat which can be very confusing, so you need to burp the system.
Hello, Thanks for the great video on the cooling system. I now have a much better understanding of the difference between the raw water and fresh water cooling systems. I am trying chase down an overheating engine issue (around 175F, gauges steaming up) on a 1977 Volvo Penta BB170A 6 cyl gas engine. Question if I may: the engine had a 160F thermostat installed instead of the V-P book recommended 130F thermostat (which I ordered). I plan to replace it hoping my engine will run a little lower. Any suggestions? Cheers!
Most guys focus on the salt water side first because corrosion happens there faster. Make sure water flow is good, inspect the impeller, inspect and clean the heat exchanger and exhaust elbow, look for old impeller vanes aren’t trapped somewhere, and be sure the intake peacock is open all the way. On the fresh water side, make sure the cap seal is good, since the system needs pressure to raise boiling point. If you replace the thermostat be sure it is designed for your engine, since you can’t replace a double valve one like this Yanmar with an old style single valve. Good luck!
@@spelunkerd Thanks, I took apart and flushed the raw water system with a hose to ensure no blockage. Plan to flush the system with Barnacle Buster at some point soon as well. Your advice is much appreciated.
If we assume coolant rarely changed, green to red coolant mixing and tap water instead of deionized water how best can we flush the fresh water side after draining? Is there any chemicals worth refilling run engine and then drain, refill with 50/50% then drain and refill with 50/50%?
That's a good question. From where you are in your description, one way to proceed would be to completely drain, refill with distilled water (inexpensive at Walmart in the food section), run for a while, then completely drain, then refill with your new coolant. Deionized water is interchangeable with distilled water in my opinion. It is getting harder to find concentrated coolant. Many stores and dealerships offer only premixed.
My anti siphon valve is leaking on my starter. I plan to order a new one tomorrow. My is mounted flat. Should it be mounted vertical like yours? Keith
Yes, orientation is very important for those things, although some designs vary. Gravity keeps the salt water from refluxing back into the exhaust manifold.
Hello, after watching your video I checked my Yanmar 3GM30F engine on a 1987 Jeanneau and noticed that there is no anti-siphon valve but rather a T-connection where your anti-siphon valve sits and a smaller hose that goes from the T up to the level of the cockpit and then down into the engine compartment - open hose at the end. Is this something that needs to be replaced with an anti siphon valve? Much appreciated. - Madison
That's an interesting design. Water normally takes the easy pathway out the exhaust, assuming there is no obstruction to that flow. With no obstruction, water pressure won't back up enough to reach the height of the top loop. Then when the pump shuts off, the vacuum is immediately broken and water can't siphon backwards into the boat from the exhaust. The only difference is the need for a long tube with a very high loop, and the assumption that the downstream flow will never meet an obstruction. Ultimately it will work the same way, but failure modes are different with different risks. If the downstream pathway obstructs, and if the pump is capable of pumping to that height, the salt water pump itself could fill your boat with salt water. I would probably leave it alone, especially if you can prove that this was the way your Jeanneau was designed.
Hey thank you for all the information 🙏🏽
My weep hole is leaking, and I already ordered a new pump. My question is: can I still drive in this time ? Because the new pump will arrive in around 3 weeks, but I have to drive a lot in this time 😢
I have a Yanmar 4jh-dte.
If the pump is not squealing it is probably safe to continue using it, but be sure not to let the reservoir run dry. Keep a close eye on your engine temperature and be prepared to shut the engine off immediately if temp rises.
Hi. This is very good and informative, but I'd like to ask about a small aperture through hull continual flow when the engine in running. I have a 40 litre calorifier around the same area as this through hull fitting, but as yet have been unable to trace the route or source. Can you shed any light on the reason for this flow? BTW this through hull is near the stern just above the water line and it is slightly warm. Thanks
Do you think it might be discharge from a waterlock muffler? My calorifier is separate and it does not discharge water at all, but if your calorifier is heated by salt water that has mixed with exhaust, you might be seeing discharge there. Some engines have no antifreeze and are simply cooled by lake water flow through the engine head, in which case you don't have the option to warm tap water with circulating antifreeze.
@@spelunkerd Thank you for that possibility. I am in N Ireland and the boat is on the hard in Greece. I will investigate further in March 2023
Great video. One question on replacing the coolant. Is there a bleeding procedure to ensure all air is purged from the system when adding new coolant. I may have missed that step in the video. Thanks
Fill it with coolant at the heat exchanger cap on the engine, and fill the reservoir too. Leave the exchanger cap off and start the engine. Add coolant as the level drops. Wait for the thermostat to open while carefully adding coolant. Watch for air bubbles and a change in temperature of the hoses coming off the engine (this will show the thermostat has opened). This takes about 10 minutes. While waiting, don't forget to verify that your salt water flow is adequate, and you haven't forgotten to open the seacock. When the engine reaches operating temperature, shut the engine off and immediately put the heat exchanger cap on tightly. Let the engine cool overnight and then next morning recheck levels at both the reservoir and the heat exchanger cap. It is normal for the heat exchanger level to rise and the reservoir level to fall overnight. This shows the automatic burping process is working. The next day out, let it run til warm, then shut down as usual. Recheck levels a couple of times over the next week, it is very common to need more fluid as air pockets are purged. This procedure is called 'burping', similar in cars as well. Some engines have a petcock to do this more easily but in small engines like this they are usually absent. I show how to do this in cars in the automotive cooling system playlist on my channel. Good luck, be careful with hot coolant, and if the engine overheats shut down immediately and think about what went wrong.
Hi Dave, awesome explanation - and dedication. Just blows me away. I had an overheat alarm on my Yanmar YM 2/20 just after having had the piping done to connect the freshwater system to my boiler. By a trained Yanmar pro. But he apparently left w/out making g sure the system is bubble-free. Now I am doing his job and wondering why you left out the exchanging of old coolant (and bleeding) from the pipes connected to your boiler? Aren't they just part of the regular burping process from the coolant system of the engine once the thermostat has opened? That got me wondering. Thank's a bunch for a quick note!
Thanks! Here in Florida learning sailboat maintenance in real time, and this is a big help. I just have one question.....
Is that a Tri-City Americans logo on your shirt? WHL team of legend goaltenders Ollie the goalie, and Carey Price?
Ya, my son played with Tri-city several years ago. The team is really well organized, outstanding management.
Hey great explanation I actually have a question and really need your help my yanmar in my 35ft C&C sailboat doesn’t want to go into gear either forward or reverse engine starts but when I change gear it doesn’t move RPMs increase if I add to it but doesn’t shift I checked the transmission box oil is good engine oil is good I am stuck any suggestions
I don't know. The last time I saw a boat like that, the prop had fallen off. Presumably you can see the prop shaft enough to know if it spins. I'd go down to the transmission and try shifting right at the gear handle on the transmission, in case a lever has dislocated. My shift handle at the cockpit has a dislocation mode to allow higher rpm starts in neutral.
@@spelunkerd thanks yea I located it and now I am going to try and shift it at the box
If the fins of the impeller break off what is a good to retreave them?
The plastic vanes will likely drift on to be lodged against the heat exchanger, or perhaps in the hose connecting the pump to the heat exchanger. I did a video "how to clean a Yanmar marine heat exchanger" showing how to get at that part where the fins are likely lodged. The good news is it is easy to get at that area by simply removing the hose and undoing four bolts that are on the front of the engine. You could even do that at sea, though if you don't have new gaskets it might leak a little after you're done. If you haven't cleaned the heat exchanger lately, you might want to do that at the same time.
Great video. One question, there is much written about mixing green and red coolant being a very bad idea. I noticed you went from green to red here without flushing with fresh water in between. What are your thoughts on this? Is it an issue?
You make a good point. I don't know what the previous owner used, and coolant color is no longer a reliable gauge. So, whatever I used was going to be a change. The data sheet on the new coolant claims to be compatible with traditional ethylene glycol, so it is probably OK. Yup, a purist would say to use distilled water, flush again, and put in the new coolant. With the residue found at the drain plug, I'm going to end up doing that anyway pretty soon. In the long run, switching to a coolant with antioxidant properties should be a positive, not a negative.
@@spelunkerd I had the same problem with the blockages last time I changed. I have just swapped out the calorifier so am thinking that a proper flush and change is in order. Have you ever considered running the hot water take off hoses into a bucket of water and running the engine? I’ve not tried it but thinking that it may be a good way to flush the system, allowing the crud to sink to the bottoms of the bucket.
@@dickonberriman3040 In the 'old days' of automotive repair, we did just that, and it is shocking to recall it was standard practice to let it go into the storm drain. They still sell the adapters for garden hoses, but few use them. Occasionally there is a reason to back flush a heater core, to try and dislodge crud, but boats don't have those. Yup, that would work, and you could take those fluids to the local recycler for free.
Smart phones have water detection strips, that will turn blue when wet and stay blue even if dried. Would that be a smart solution to have a permanent wheep hole check for water? Maybe they turn blue anyways because of the moisture so might not work.
Gotta love creative thinking like this. Unfortunately in a boat, dew condensation when ambient temp falls is so prevalent that I'll guess all strips would show false positives very soon.
Question:
What if the top (fresh water) hose from thermostat housing is colder than the bottom (fresh water) hose from the outlet of the heat exchanger?
I have a hunter 34 and I recently flushed (with your videos help) out the old coolant and have noticed per this video that the top hose should be hotter than the bottom hose and I'm getting the complete opposite. Please advise. Your video has helped me a whole lot sir thank you.
I would go to your exact dealers repair manual to verify routing of coolant to be sure it is the same as shown here. If the top hose is cool, the thermostat has not yet opened, so you need to run the engine for longer. Just after working on the system you'll also have trapped air pockets in hoses which may heat up at a different rate. As shown, I ran the engine with cap off to burp air from the system, but final burping always takes a few more heat/cool cycles with a properly sealing heat exchanger cap. So, keep running, keep adding coolant, and intermittently check to be sure the fluid level at the heat exchanger cap is full. Good luck!
@@spelunkerd thanks you very much for your time and guidance. You were right it was that the thermostat was not open yet...after reading your reply I went amd bought a laser temp. Gun and saw that I was not up to the 71c the thermostat is rated for so I waited and it opened up. As far as the air in system I disconnected the two hoses going to the heat exchanger and blew out existing coolant and filled the heat exchanger and lines directly from the Jose's amd then reconnected them and filled the heat exchanger on the motor separately. I will continue to check the coolant level everything I turn the motor on...thankyou so much. I couldn't have done it without you and am one of your newest subscribers.
Your videos are excellent and I learn a lot from you. Thank you. Thanks for answering our comments. My 3GM30F has a continuous stream of pure (i.e. no combustion vapors- proven with a number of tests) air bubbles coming out of the top of the heat exchanger. Crankcase oil and antifreeze are not polluted. Exhaust is normal. Power is normal. I pressure tested the heat exchanger with 16 psi for 30 minutes both with a cold and hot engine. Also tested with decompression levers both on and off. All tests show no leakage. This is not normal engine "burping" bubbles since they never go away. Any ideas where the air is leaking in (since the heat exchanger runs at about 13 p.s.i.)? Would it be ok to simply ignore the problem? I would have never known I had a problem if my overflow tube to the external antifreeze tank were not transparent. Thanks again for your time and attention.
Jon Fischer
That's an interesting story. If not done already, I'd do a test for combustion gasses in the cooling system, with a device called a 'combustion leak tester'. It fits onto the heat exchanger cap, and the blue liquid inside turns a green color if exposed to the nitrogenous waste gasses of an exhaust leak into the cooling system. You might be able to borrow the tool from a local tool store, but the kit itself is only about $70. It's a screening test for a small head gasket leak. Another place air can be making its way in is when the engine is off, from a pinhole leak that is evident only when under the negative pressure caused when trapped air begins to cool. You can get ball valve effects that only show up when under negative pressure, perhaps explaining why your pressure test is negative. Have a close look at the hose connecting your coolant reservoir to the heat exchanger. Even a pinhole leak in that hose might be enough to cause your problem. Likewise have a look at the seals around the cap, if the cap seal is bad it could give recurring issues with air finding its way back in after the engine is turned off. If in doubt, replace the cap, it is inexpensive and not easy to test. Make sure the coolant reservoir never drops the fluid level below the siphon tube, otherwise you'll get trapped air that can take weeks to clear. I did a really old video of such a problem in a truck, titled "mystery of the gurgling heater core". It turned out air was being drawn back in through a bad heater hose connection, it was frustratingly hard to find. The hose was leaking only when under negative pressure, letting air in but not much else. Good luck!
@@spelunkerd Thanks so much for the quick response. Today I purchased a combustion leak tester (only $39 from Harbor Freight). You were right: the chemical turned green. I will replace the head gasket. Do you suggest I bring the head into a machine shop to check for microscopic leaks? Any other advice for my upcoming adventure? Thanks again for everything.
@@MrJonFischer Yes, I would get a machine shop involved, to at least inspect and resurface the head. If your time is valuable, and if you want a professional result, you might ask them how much more it would be for them to do more, resurface the valves and valve seats, replace valve stem seals, inspect injectors, etc. Some mechanics hand the head over to the machine shop to subcontract it all. Hopefully the head is not cracked. I am definitely not an expert in this topic, so I would be searching for advice everywhere. You'll need a torque wrench to do this task. There is at least one youtube video set by a complete amateur on doing a head gasket on the 3GM Yanmar. He got over his head but powered through it.
My training is in automotive engines, marine diesel engines have been a new experience. In automotive engines, a head gasket leak is almost always the cause when exhaust gas gets into coolant. As I think about marine engines, I wonder about the chance of a leak between the exhaust manifold ports and the coolant reservoir inside the heat exchanger. The two are separated from each other by a wall of cast iron, but they are designed to exchange heat to cool the exhaust output. I suppose it is possible there could be a rusted pinhole leak there, although with no decline during a pressure test it would have to be small. In any case, to do the head gasket, a first step is to remove the heat exchanger so you can inspect it at that time.
@@spelunkerd Thanks for the advice. Of course, I will examine the exhaust manifold gasket and perhaps do a longer term pressure test on the heat exchanger. Hopefully, my visual inspection is good enough. I hate to go to a head gasket replacement if it is not needed. One other thought: should I try a "leak stop" chemical in the antifreeze before taking the engine apart?
Did my first marine oil change on a friends 1980 Yanmar 20hp in his 36 ft hunter. As the vacuum started through the dipstick I first drew clear water. 4 to 5 Ounces, this is where I think that this is relevant, The engine had been run for at least 15 hours the week before in one to three hour intervals 1800 to 2500 operating speeds. Is the engine running to cold?/ thermostat problem
That's alarming. I don't think running a little cold would do it, I would be thinking of a head gasket leak, or maybe a problem with the salt water elbow, or maybe the dipstick was not sitting correctly and water splashed through the dipstick tube into the engine. I would not run the engine until you have a close look at it, and unless you're comfortable with diagnosis in these engines you would be wise to consult a pro. If this were my engine I would pressure test the cooling system with a pressure tester. I show how to do that in automobile engines on my channel. It requires some special equipment, though you may be able to borrow the gear form an auto parts store. I would also disassemble the salt water elbow to look for any defect that might allow salt water to make its way back from the exhaust into a cylinder through an open exhaust valve, and I'd check the antisiphon valve that is on the distal side of the salt water output to be sure it is not stuck shut. After flushing the oil and oil filter I'd then run the engine for a couple of minutes, maybe using a chemical tester to look for exhaust products in the cooling system to look for a head gasket leak. I'd then shut the system down and change the oil and oil filter again. If the oil dipstick is not installed correctly, it is possible to spray salt water through the dipstick tube in my Yanmar engine. The tube is right below the heat exchanger and in a best case scenario that cause would be a relief. Let's hope for the best.
@@spelunkerd Interesting that you brought up the dipstick, The day we were test driving riding on the boat the rear portion of the exhaust manifold failed were the salt water is mixed to cool the exhaust. The part was replaced before the transfer of the boat. Sprayed exhaust and see water every where. The dipstick had a very loose feel and I wrapped some plumbers tape (Teflon) around it to tighten it up until I can get a proper O ring on it when I did the oil change. This may be the cause of the clear water at the bottom.
I will check for exhaust products and a friend has a pressure test kit. On an old head gasket how much pressure is enough i do not want to cause a failure.
@@emilopffer1069 The gauge on the test kit will show you, but typically these mount about 15 psi over atmospheric pressure when the engine is running normally, so you're safe if you stay below that. It should hold for at least 15 min with no sagging of pressure, watch for external leaking. With water in the oil pan, leakage may be internal, hard to see but the pressure drop will be your clue. Have a look at the weep hole while pressurized.
@@spelunkerd Thanks weekend project, appreciate the responses and speed of response : )
Yanmar header tanks ('subtank') should be removable by sliding up their mounting fitting. This may not be obvious due to its position. Emptying, cleaning and filling is then a lot easier and safer.
Can anyone recommend a pressure test kit that will fit the Yanmar 3GM30F heat exchanger? I've bought a test kit as recommended here, but I can't get the cap to fit as the depth is too shallow compared to the auto radiators the kit is designed for. Thanks
David
Isn't that annoying! I have two kits, for that very reason, on other vehicles. Today I went to the boat and found that both kits contain the correct adapter. The part that fits is Astro 7858-3. The knockoff generic kit doesn't have a name, but that adapter is one of the most common adapters available. Flat stainless, with no plastic. Note that to get the bottom seal to work you need to press the adapter down firmly and rotate, a silicone lubricant might allow it to slide into place more easily. The lower seal is spring loaded to allow a tight seal. If the bottom seal is a problem, then a hack would be to clamp off the hose leading to the reservoir. Put vacuum hose onto the jaws of locking pliers to avoid damaging the tubing, or get dedicated hose clamps.
@@spelunkerd Thank you. Your videos are the best!
Astro 7858-3 is $20 but $80 to ship to the UK! Looks like I'll be trying your other methods!
@@DavidRea2710 You might ask at a local auto parts store if they will permit you to borrow or rent a cooling system pressure tester. In the US this is commonly done, you put a deposit down and can get a refund if the equipment is returned clean and unbroken. Alternatively you can carefully run the engine and look for leaks, it is a little risky because of moving parts, but possible.
ON THIS I WOULD USE waterless coolant. then you never need to change it. it also wont do any damage. No alkali. no corrosion. New technology. great for marine and classic cars.
www.summitracing.com/parts/evn-ec53001?seid=srese1&gclid=CjwKCAjwt8uGBhBAEiwAayu_9fJDREZo95tROm1isohpvWDwkLAQIpWXh6c9aAALQ1pKvYN66iUgBhoCF0MQAvD_BwE
I find this a really interesting point. Several years ago I reviewed this intriguing topic. The weak point of internal combustion engines is definitely water. Through the years I have done more repairs on cooling system problems than any other.! I don't know anything about its use in marine diesel engines.
I didn't understand what you said in the begining about the sea water coming and meeting fresh water
In a classic car radiator, the exchange of heat happens between air and coolant. In salt water boats, they use a steady stream of ocean water rather than air. To exchange heat between the salt water and the coolant, a heat exchanger plays the same role as a radiator in a car. It allows exchange of heat without letting the two mix chemically. In exclusively fresh water boats and outboard motors, lake water itself is pumped into the engine to cool the cylinders directly, with no heat exchanger. The reason that doesn't work in salt water is galvanic corrosion that eats away at the engine from the inside out.
Can you please explain where wire from alternator on the engine is supposed to go? The place says "Bat". So, should it go to the battery selector, the positive side? Or the actual battery, again positive?
Good question. Either will work, but if you wire it directly to the battery you lose a minor security protection because the operator doesn't have to get into the cabin before starting the engine. So, I wire mine through the battery selector, so that anybody who tries to start my engine needs to bypass the key somehow AND get into the downstairs cabin to turn the battery selector on before he can start the engine. Security protection for these little diesel engines is surprisingly bad, since you can even start the engine without having the key on, by simply hotwiring the starter motor. It's not good for the engine or engine electronics to do that but a joyrider doesn't really care about electronics. By wiring the starter motor through the battery selector you do introduce another potential source of voltage drop, especially considering that the signal wire from the starter switch doesn't have a relay. But from a practical perspective it works fine. And by wiring it through the battery selector you can turn the whole system off (bilge pump excluded) so there are fewer possible sources for parasitic drain.
@@spelunkerd Ok, so I will wire it to the battery selector. But, do I need to insert a fuse breaker into the wire?
@@tomjoad1060 No fuse. The starter motor draws up to 200A, so regular fuses wouldn't stand a chance.
Thank you, will try it next week. Don't know much about electricity, hope there will be no fire...) I once started a fire on my yacht, because didn't know how to handle alcohol burner. That was scary!
@@tomjoad1060 I've had close calls, too. One day I was on a boat with a running diesel engine, and it wouldn't shut down even after turning off the fuel, opening the fuel rail to air, and restricting air flow. It turned out the starter motor would not disengage even with key off, and the typical sound was muffled by the engine noise. I honestly missed the diagnosis but when smoke appeared around the engine somebody turned off the power and the starter quit. The solenoid had frozen in the on position. Close call, and a humbling experience!
I just changed the impeller in the salt water pump. There was a brass or bronze coiled spring that supported or reinforced the rubber seal (part #9 or 8 on the Yanmar 3gm30 parts catalog, fig. 32). This coiled spring was twisted out of shape. I don't see that actual item in the parts catalog. Can I just leave that out? Has anyone dealt with this? thanks.
I did a rebuild video for the salt water pump, so I suggest you go there and watch that first. It's more detailed than you need, but it gives good shots of the seal spring toward the end of the video. I'll assume you are referring to the seal spring, which comes with the new seal. The purpose of that seal spring shown in my video is to hold the seal shut, tight around the shaft. It is unfortunately easy to damage a seal spring when you install the seal. The spring is always on the higher pressure fluid side, in this case the water side. Most of us apply a little grease or silicone grease onto the spring to try and reduce the chance of dislodging the spring when installing the new seal. If the spring is damaged, I would buy another seal, it needs to be there. If you already installed it, wait to see if it leaks, but buy another seal now so you can replace it again when it fails. You'll know when it fails because you'll get a steady drip of salt water from the pump when engine is on.
@@spelunkerd Ahhh. Thanks so much. The rebuild video was very helpful. I have a 3GM30F, and after the second trip to yanmar parts dealer, have the correct sized seals. However, the original seal is a different design than the replacement. The orig’l seal is affixed to the pump’s housing with a flange, as if to hold it in place. The rubber of the seal body is a bit worn by the seal spring and probably should be replaced. On your model, the seal is sandwiched btw the impeller and the interior pulley on the other side. My question is: if I remove the affixed seal and replace, I may need a spacer on the non-water side. Would a nylon washer(s) and/ or a spacer be a good option? I don’t think stainless or brass would be good here. The parts store was out of the washer that goes on the non-water side. I can re-use my washer, but it does not snug up against the seal.
@@danielconnolly2553 I don't have any experience with that design, but your thinking sounds rational.