Isuzu NPR 5.2 Blown Head Gasket Repair - Part 1
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- čas přidán 6. 10. 2016
- Isuzu 5.2 4hk1tc blown head gasket repair, info, and general tips. Pressurized cooling system was cause by leaking injector tubes.
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4 years ago but I find myself replacing a head gasket on this very same engine in 2020 I really appreciate you uploading this video and the helpful reminders😁
Glad it helps! Yeah that’s one heavy cylinderhead
Hi thanks for the info! My 4hk1 has motor oil mixing in the radiator fluid I already rebuilt the oil cooler but its still mixing. just wondering if I can try replacing the injector tubes without removing the head or what you would recommend Thanks!
Thanks for sharing your insights, especially the part at the back of the head above the bell housing. I think someone didn’t use enough sealant or the factory install is now just leaking on mine. Did you have to take the head back off to add sealant or is there a trick where you loosen up the bell housing and add sealant? Would love to hear there’s an “easy” fix.
Also, do you know if the shop manual for the 5.2 is available online as a pdf? Thanks again!!
Hi Brad
I'll do a pressure test on the egr cooler tomorrow. How manny psi would be safe? Also do you know do u know the torque for the injectors? Thanks Brad
I have a chance to get one of these trucks super cheap. it has low compression in two of the cylinders, that's all I know about it. It has the 4HK1 engine, its a 2007. What do you think it would be? Is it worth buying and fixing? Any advice would be greatly appreciated.
Hi friend, a question about how many pounds of pressure the conn rod screws to. how many pounds the crankshaft screws to. and those of the cylinder head. I am doing a project at home and I would like to be sure of that information
Hey, awesome video! Whats the labor time to do the head gasket on one of these?? Thanks for the help
Did you fix it?
I have issues with bubbling an the reservoir spilling coolants an my radiator hoses feel like lot of pressure radiator is good an clean new cap new thermostats new gage an me thinking it was the head gasket I used blue devil to fix it truck runs an drives great besides it’s going almost to over heating but doesn’t what you think it could be
The injector seals are letting combustion get into the cooling system in the cylinder head. The injectors are cooled with coolant in the cylinder head. Of course a head gasket could also be the issue.
The very top line is tdc mark on the engine side??
Do u have doing oil pan gasket
Hello , I have 03 ISUZU npr with 4.8L 4he1 . Truck runs and drives well no problem with it it does leak oil from the exhaust manifold down to the side of the engine . I driven it like that for about 60k miles with no problem . I do see the truck has a lot of blow by I took off oil cap and I see no white smoke but a lot of pressure I put gap backwards and it blows the cap off .. what do you think this would be truck has 344k . So wounded if it's even worth overhauling truck still
Runs and drives very well no problem . I would appreciate your feedback thank you
With 344k, just keep an eye on all of your fluids and keep running the truck. Definitely signs of a broken piston ring or head gasket. Is it over pressurizing the cooling system? Pushing any coolant out of the system?
Hi man where can I get the manual am tearing mine up thanks
Hi, brad ive just had head off a 2010 n series 5.2,lightly skimmed and a 2 hole gasket fitted,can u give me some pointers on setting camshft/idler gear backlash as the idler gear is floating and tricky 2 centralize,thanks.
Andrew
How do you determine which gasket (no hole, 1 hole, or 2 hole) to use after head is skimmed?
Cheers Thank you
What manual did you download can you share a link
Thanks for the video.
I assumed the head gasket blew on my 3.9l diesel in a 95 W4500 when I saw excessive pressure in reservoir. New head, gaskets, radiator rodded out etc. Put back together & ran great, bubbling in reservoir was gone & temp was perfect. 3 weeks of daily use & the temp suddenly spiked & pressure returned. It is now parked because it overheats terribly after 30 minutes of driving. Cooling system can't keep up with the level of exhaust heat coming in. Never saw water in oil.
I couldn't quite make out what you were describing the problem was in the beginning- 'brass inductors'?
Your thoughts please.
Yes those were the same symptoms of my 5.2L. Rebuilt the top end once before, ran fine for a few weeks… coolant built pressure, which causes a air pocket, and starves the water pump…. Overheated.
The brass injector tubes are in the center of the cylinder head, like a hemi spark plug. The injector tubes are cooled by the coolant. When the engine overheats they are prone to fail because iron head and brass injector tubes react to heat differently.
The only other cause of the pressurized cooling system would be a crack in the cylinder head. The head will need to be pulled and pressure tested at a machine shop to truly find the problem. Do your research for a reputable shop.
Hope this helps
Hi Brad well I'm not a mechanic but I do know how to karate chop two number two pencils in half if one karate chop, what do you got to say about that mr.? I had a carburetor problem in my 92 Isuzu, I karate chopped it it didn't work, in fact I accidentally karate chopped my radiator hose off, now I've got a blown head gasket I've tried using steel seal it's not working, should I go ahead and try karate chopping my block don't know what else to do here Brad what do you think?
Hi Brad
The torque the same even for the small 2 bolts at the rear? Thanks Brad
western4425 the 2 small bolt on the rear are around 18 ftlb. Make sure you use rtv silicone on the aluminum bell housing
How do you remove water pump
Hi Brad can you tell me if this torque is correct for 07 Izusu NPR 5.2 head bolts? 1) 72FT LBS 2) 108FT LBS 3) 30 - 60 Degree Also there are 2 10mm bolts at the rear of the head. Is the torque the same for the 18 blots 14mm and the 2 bolts 10mm? thansk
yes that all sounds correct
Sorry for the late response. Non of the liquids are mixing and I think that the radiator hose is over pressure. I also change the cap on the radiator and still had the same problem. I have remove the cylinder head I don't see any cracks. What do you recommend me to do next? Thanks
If you have removed the cylinder head, bring it to a machine shop and let them do a pressure test. Sounds like it could be leaking injector tubes but only the machine shop can confirm that. Goodluck!
Im having the same problem did you find put the issue
Hi I have a problem, I have coolant returning to the reservoir. What do you think it could be?
are any fluids mixing? does the rubber hose from the radiator to the engine feel over pressurized?
great video, I have a customer with the same engine, same problem. only thing is I've never done one before, so I don't know how much to quote him for the labor, in hours that is. little help?
Removing the head is not that hard, but it is pretty heavy. The cylinderhead has to be pressure tested because of the injector seals can leak
Do you have any suggestion adjusting the valves on this engine? Ours has close to 200k so it's time. I've never done this engine before....
Valve adjustments are very easy on these engines. Take the valve cover off. Get a feeler gauge (look up the valve lash for your specific engine) and slide the feeler under the rocker and top of the valve spring. Need to make sure the rocker is not under any load when adjusting.
Brad Raziano regular engine!!!! THANK YOU. I'm our other diesels it's a bitch!!!!! Thank you so much. You're doing a good thing on here for us
Glad I can help!
Do you know what's the average charge for a pressure test. Do you know what's the psi when they do the test?
western4425 I can't recall what it cost. They seal the combustion chamber on the head and submerge it in water. They are just looking for bubbles at the normal compressing psi
Where do you find the service manual for this truck? Can't find it anywhere!
Hello. Were you able to find a solid manual? I'm also looking for one
@@byrondelgado2833 unfortunately not, however there is the engine (4HK1) manual PDF online. It isn’t too hard to find, if you need to do any engine work. I gave up and took it to the workshop haha
HI MATE , FIRSTLY THANKS FOR GREAT VIDEO , BUT I HAVE GREAT QUESTION IF CAN HELP BY GREAT ANSWER , THE ISUZUTRUCK JAPAN 4hk1ENGINE WITH INJECTORS ELECTRIK. WAS RUNNING GREAT , AFTER CHANGE GASKET HEAD CYL. NOW TRUCK ENGINE CRANKING BUT DOEAS NOT START, TIMMING ,CRANK OK , CAM SHAFT TIMMING OK, DOUBLE CHECK OF PUMP TIMMING OK , AND ALSO WE CHANGE FROM ANOTHER TRUCK COMMON RAIL PRESSURE VALE AND SENSOR ,WITH CAMSHAFT SENSOR AND CRANK SHAFT SENSOR ALSO SAME NO START , IS IT POSSIBLE EASY LOOSING INJECTOR CODES IN ECM AFTER REMOVING BATTERY ABOUT 2 WEEKS WITHOUT BATTERY ? OR ANOTHER PROBLE , PLEASE IF YOU HAVE EXPERIANCE ABOUT THIS MATTER PLEASE HELP . THANK YOU
The battery being disconnected is definitely not the problem. Man thats a tough one since it was running perfect before the head gasket. I would recommend doing a compression test at this point.
Hi Brad
I took my 5.2 Isuzu NPR cylinder head to a machine shop. They resurface it and install 16 valve guides. They did a pressure test and no cracks. I installed the cylinder head and it work good for about a week. Then it started pressuring the coolant. It's not mixing with the oil. Any idea of what's causing this? Thanks
western4425 Shoot, did you test pressure test the egr cooler? All the injectors are in tight?
western4425 was the machine shop aware of the brass injector tubes being problematic?
cyl head cannot !!!!!!!! be machined due to cam gear clearances
Do you have a link to download the manual?
Did you find out where the manual can be downloaded?
Bonjour je peux avoir le manuel svp
I have coolant overflow to the little tank
If I suspect I have the same issue could I remove injectors and pressurize coolant system and watch for coolant to leak past a sleeve
If you pressurize the cooling system it would leak down into the cylinder
@@RaztechPowersports thanks for the reply btw like ford 7.3 and duramax 6.6 the sleeves are replaceable are these sleeves similar
Rubenjr. Da Gadite yep same concept.
@@RaztechPowersports thank for your help I pulled the head just finished gonna have it done up and try that oversized gasket and hope for the best....
@@GaditeKing Update?
Which gasket is oversized?
Where are the glow plugs??
Is a few drops normal from that blow by tube or is that a sign of the piston rings being bad?
Do you have a lot of pressure coming out put it?
@@RaztechPowersports taking it to the shop friday ill follow up and see whatcha think
@@stitchthisditchthat259 yeah sounds good man I’ll try to give you my best input. Compression test is probably your best route if it’s going to a diesel shop.
WATER OUT OF TURBO ON 5.2 ENGINE IN ISUZU 2010 CREW CAB 4X4 AS REPLACE THE TURBO
fuck me. Ran at red for 30 minutes? I pull over and waited when mine was 1/8" from the white line before red because that was too warm for me. Thank you. this helped me know I'm probably ok with my 88 npr! Having heating issues. Radiator is getting cleaned right now so I hope that fixes it. New thermostat and sensors too
Ian Baldwin I would def recommend buying a new radiator since its a 88. These radiators have problems with corroding internally. Is your 88 a 4.8 L? If so those motors are much stronger due to the thicker cylinder walls
I forgot to tell you that my truck is 07 Isuzu NPR 5.2
Sorry for late response, no non of the liquids are mixing. I think that the hose was over pressuring. I also change the radiator cap.
@@western4425 did you fix it?
Update?