Diagnosing and Fixing Overheating VW Mk1 Mk2/A1 A2
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- čas přidán 27. 07. 2024
- Diagnosing and fixing radiator fan and thermostat issues.
Fundamentals of coolant system video: coming soon!
Coolant flush video: • VW Coolant Flush Mk1 M...
AC switch video: • AC Switch Installation...
Tools/Parts Required:
- Multimeter amzn.to/3jWA5aE
- Thermostwitch 1987 and older: 823959481F amzn.to/3RPgdaa
- Thermoswitch 1988 and newer 191959481C amzn.to/3LijX16
Torque specs:
- None :)
0:29 Normal gauge operation
1:23 What to do when your car is overheating
5:25 Diagnosing coolant fan operation (not turning on)
6:30 Diagnosing 1987 and older
7:47 Diagnosing 1988 and newer vehicle
9:07 Thermoswitch replacement
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Very impressive channel. Great videos, thank you
Well done oli. I ended up fixing the fan to permanently on, on the side of the road after the termo switch died. It’s always handy to know how to fix/bypass problems. Great video
I drove around for a while with my AC always on to keep the fan running before I got to replacing the switch…haha. Then I found out it was just a bad connection to the switch.
I hope the car is running well - it looks great from what I’ve seen in pictures!!
@@OlisGarage thanks 😊 oli. Yeah currently had a water leak from the ex owners diy fix . Replaced the water pump too . It’s running great again . Keep your videos coming I enjoy watching them .
On all my 80’s water cooled VW’s after fixing any over heating problems I replace the thermostat and fan switch with a lower temperature parts. The original thermostat and fan switch open up way to late, usually when the car is on the verge of over heating.
That is actually not correct. The thermostat is perfect for the vehicle. Upgrading to a lower temperature is unnecessary. I don’t think it hurts anything, but it’s definitely unnecessary. These cars are not on the verge of overheating. Not trying to be rude, just trying to make sure people don’t think these cars are borderline overheating.
Later VWs (I can 100% confirm through 2005-I just dug through the manual) actually used a thermostat which isn’t fully open until 105C or 221F (it starts opening at 85C). That is much hotter than the thermostat in these cars which is fully open at 87C.
The radiator fans are similar. The newer VW fans come on at 92-97C or 197-206F. That’s the low speed.
The cabriolet radiator fan comes on at 93C.
Coolant also doesn’t boil until around 115C or so when it’s under slight pressure and properly mixed.
One last tidbit. The coolant temperature gauge in the newer VWs isn’t accurate. It is literally coded to display right in the middle for a whole range of temperatures. This is so that people don’t think their car is overheating when the gauge goes slightly past the middle.
Only just found your channel... You help me on the static timing video for my mk2 golf...... 😁..... I've subscribed going to watch every single one of your videos see what else I can learn.... Mot time for my mk2 today 🤞keep up the good work 👍
Good luck with the mk2! I need to do a video on timing the engine with a timing light too, just for completeness. But the static method works super well in my (and quite a few people on the internet) experience.
Perfect time this video. Congrats and thanks
Very helpefull video .. thank u Oli
I got a 1990 Wolfsburg. Thermostat isn't opening but its new and works. Top hose definitely gets hot the bottom hose is ice cold tho. Pumps new as well
Have you tested the thermostat in boiling water?
@@OlisGarage yes I have. The thermostat is good and so is the water pump. Just put a new headgasket in 2 days ago (head was decked professionally) timing is mint and she runs like a champ but still over heats. Fan is bypassed and on a switch (i turn it on at aroumd 120f) when I squeeze the bottom hose on radiator it does put flow back into overflow tank. Could it be just reduced flow? The rad is literally the only thing g I haven't replaced yet . It seems to have flow though however the top will be hot and the bottom cold
@@OlisGarage i do not think the thermostat is opening but I'm not understanding why it wouldn't be. It works fine while boiled as does the old one
great video as always!!!
Thank you!
My only 2 cents would be to check the voltage drop when the fan kicks on. The coolant system can be fine and the fan is just not pulling enough amps due to a bad ground.
Good point. The other way to check that is to monitor the gauge. If the temperature keeps climbing and the fan doesn’t turn off, then something is wrong with the fan or the wiring.
THANK YOU. So much
Thanks!
Mine (on an MK2) failed in a way that it would be stuck in low fan speed. So after parking, the fan would just never stop until the battery runs out (but luckily I noticed it before that happened).
Oh wow, interesting. Good catch. That would’ve been upsetting if it’s totally dead!
Cute guy & knows his stuff too 😍
Hi Oli, thanks for the informative video.
Im still having some problems with my polo mk 2 where the fan wont turn on. I have brigde the switch on the radiator and the fan works and turns smoothly, i then replaced the thermoswitch, but it still dosnt come on when the motor is too hot. what else could be the problem. no fuses are blown and i have also cheked for airlocks in the system. Any advice would be greatly apreciated. Greeting from Denmark
what if my needle stays on the left hand side of the led at all times (not quite passed it) but its also 70+ where i live during summer
Thanks for your videos Oli.
Did you get the information I emailed you regarding the owners manual with all the tork settings and so on?
Apparently there is a transistor in the dashboard behind the cluster that also effects the needle. When I bought my Fox the temperature needle never went past the second line on the left. Over a period of time it did, I've replaced the engine coolent sensor, engine temperature sensor and thermostat over the period of time and noticed that the needle now indicates as to your does.
Do you think it could be a problem?
I followed your method as to the timing setup also (its like the described method in the book I have), but I do think that the inlet valve time is not correct for me as the vehicle is sluggish on the uphill (I can feel it losses power compared to a straight).
Any possible advice on what I should do?
Hello Siener, yes I did! Thank you for that. Sorry I forgot to respond saying thank you..I am not the best with keeping up with everything haha.
Hmm. There is a voltage regulator which does matter. Does your fuel gauge indicate properly? I need to review exactly what the voltage regulator feeds power to.
Put your engine to top dead center (little dot on the flywheel) and then check the camshaft gear and see if it is at top dead center. There is a little dot which should be in line with the valve cover. Google should reveal some images.
I’m currently working on making an in detail timing video, but am not done yet
I replaced my switch you are right little bit of a pain in the ass
It certainly is annoying. But hopefully the replacement lasts a long time.
@@OlisGarage keep the video coming. Incidentally I'm trying to get an Air Intake Boot. Besides e bay do you know anyone who might have an NOS part. Thanks in advance
@@walterbutscher8438 try to find the part number and just google. That’s what I do, especially for something that is harder to find.
Websites that come to mind:
Werk34 might; they’re out of Germany. Or vwheritage. Sometimes busdepot has rubber pieces like that.
@@OlisGarage thanks bud I appreciate it
vw golf mk2 1986 1.8L 8v
oil pressure dropping only when engine hot
and buzzer and oil warning light flashing .
what is done
checked oil level ok
filter changed new
oil pump checked ok
crank bearings clearance ok
high oil pressure switch changed new
the car still give the oil warning light flashing and buzzer
and coolant temp jumps over the middle and high speed fan working .
if you know please reply and help me fix my car I love in a remote place and car stopping would be a big problem .
Firstly thank you for the advice, My old thermostat was 87°c but the dealership gave me a new one of 82°C and said it should work fine, My heat gauge isn't going up and the fan hasn't really gone on because it didn't get hot enough I guess but if I Don replace the thermo switch should I still get a 1. 95°c 2. 102°c or should it change now because it's a 82°c thermostat?
Hmm. Something is wrong here. Even with no thermostat the car will get hot enough to turn on the fan in maybe 10-20 minutes of running. Are you sure that the coolant system is filled correctly?
Yes I believe it's 60% water 40 % coolant? When I breach the fan it turns on and both the top and bottom pipe gets hot,
I drove 2 hours without my cars needle even going to half when I got to my destination my fan came on, I drove home 2 hours non stop without any overheating issues, a week later I drove about 20 minutes and my car overheated and coolant all ran out the top as it boiled over out of the bottle, I checked my car and noticed the thermostat didn't open it was stuck on closed when I tested it, so I replaced that but they gave me a 82°c thermostat not a 87°c
Replaced the thermo fan switch and its fixed thank you
Is that an RD engine code?
So, I changed the 2x coolant temp sensors/senders on my ‘89 Jetta 1.6TD. My temp gauge kept randomly dropping to zero so I figured that would fix it.
Looks like I must have put the wrong sensors in though. Now gauge doesn’t go passed the solid white “cold” section and the glow plugs are staying on much longer than usual.
I put in part #025906041A. After some googling, I’m a bit more confused. Looks like I should use part #251919501A or 251919501D but can’t figure out which. Anyone know the right number or the difference between these 2?
Gauge randomly going to 0 indicates that the gauge is broken. I have a video on repairing the gauge.
I’ll dig a bit about the coolant temp sensors
Have jetta3 i have the waterpump and termostat but still overheated
Is the thermostat opening at the right temperature? In my thermostat replacement video I show how to test a thermostat in boiling water.
Is the fan coming on?
Is the radiator clogged?
Does the water pump work?
Here’s a weird one. My fan comes on if I turn on the A/C. It also comes on if I shut off the car and it’s hot. But it does not come on when the car is running and the engine is hot. So if I’m idling for a long time it starts to get pretty warm. Is that the fan switch?
Year and model?
But yes, fan switch. Ac makes the fan come on automatically (even if ac doesn’t work). Then you also have an after run fan switch that makes the fan come on when you shut it off. Mounted on the back side of the valve cover.
@@OlisGarage it’s a 1989 Jetta GL 1.6TD. Think I’ll just replace relay, switch, and fuses anyways. It’s all old and those parts are all cheap. Thanks
hello friend do you guy do repair ? How can i get in contact with you