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M38 head gasket
Posted: Sat Feb 08, 2020 2:06 pm
by baios
Please is it dificult to change a faulty head gasket on my M38? Find a water while changing my oils

Posted: Sun Feb 09, 2020 12:48 am
by wesk
For someone who has never removed a cylinder had it can be quite difficult. So it is not possible to tell you what the level of difficulty will be for you to change a cylinder head gasket unless we know your level of mechanical capabilities or experience.
If you are a reasonably experienced mechanic then it should not be difficult at all. Just follow the directions in the manual.
Posted: Sun Feb 09, 2020 1:26 am
by baios
From 1to 10 i Will say 5

so i have the manual so i Will follow the steps. But what is suprised me is that my M38 has only 1500miles on it from my restoration.

soo propably my mechanic put a faulty one or

What else...
Posted: Sun Feb 09, 2020 2:36 am
by wesk
Water in the oil can be caused several ways. Leaking head gasket, leaking bolt threads, block cracks. Since you mention only 1500 miles since overhaul begs the question was the correct installation procedure followed including a re-torque of the head bolts after an initial short run-in period.
Posted: Sat Mar 07, 2020 7:31 am
by baios
Posted: Sun Mar 08, 2020 12:00 am
by wesk
Other tahn some localized severe corrosion I really can't see any other issues. It would be easier and more accurate to offer an analysis of the condition of the block deck & head after they have been properly cleaned.
I see you have a large puddle of antifreeze in #4 cylinder. Did you neglect to drain the block before removing the head or was the antifreeze already flooding #4 while the engine was being operated?
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Posted: Sun Mar 08, 2020 12:48 am
by baios
Thanks i will follow your advise.
Now i drain the antifreeze from the radiator only.then i started to open
the head and i saw that antifreeze on 4 cylinder. Did i make a mistake in sth?

Posted: Sun Mar 08, 2020 2:46 am
by wesk
If the head removal was only for minor gasket or valve work then since you did not drain the block thru the petcock on the right side of the block you now must change the oil and flush any antifreeze from the oil pan. Also then you would know for sure how that antifreeze got on top of #4 piston. By draining the block before pulling the head you can avoid any liquids being trapped in the head and released the instant the head becomes loose. This way the presence of antifreeze in the #4 bore would indicate it was leaking into that bore while the engine was operating.
Posted: Mon Mar 09, 2020 5:15 am
by baios
Posted: Mon Mar 09, 2020 8:00 am
by wesk
The gasket looks to be correct.
I see you did not have a machine shop clean and prepare your block deck and cyl head face for their refit.
Have you straight edge checked both surfaces for trueness? To insure all leak sources are sealed you must remove all your studs and clean threads and then install all the studs with sealant on their threads that thread into the block.
Did you remove all the valves and clean and inspect their faces, stems and seats?
Posted: Mon Mar 09, 2020 10:34 am
by baios
ok im happy that the head gasket is correct althought from one side is aluminium and a mechanic told me that maybe it will not seal very well. the other side is permenite which is good sealant.
checked both surfaces seems very good. trying to remove all studs but the most of them cant move at all.
anyway i will go on and see

Posted: Mon Mar 09, 2020 2:55 pm
by Ryan_Miller
Don't forget to re-torque the head bolt nuts after the engine has warmed up too!
Posted: Mon Mar 09, 2020 8:19 pm
by wesk
For the head studs that seem frozen in their threads first you try continually soaking them with penetrating fluid for a few days and if that doesn't work then use a torch to heat them red hot. Clean the threads afterwards and test fit the studs. If they are loose in the block's threads then buy new studs.
Posted: Thu Mar 12, 2020 1:47 pm
by baios
Posted: Thu Mar 12, 2020 8:21 pm
by wesk
The course threads at the top of the photo came out of the block. Those threads are actually the threaded insert that ripped loose from the whole in the block.The insert or what is often called a "helicoil" was an earlier repair to the threaded hole in the block that has failed. Not only do you need a new stud, you also need to determine if the block is repairable. I suggest this is a job for an automotive machinist.