Cheers BB'ers,

I have the pleasure of replacing the headgasket on my 88 740t. 150 psi in cylinders 1 and 4 and 50 psi in 2 and 3. I have a couple questions. Has anyone had to replace a headgasket because it simply wore out? This is what appears to have happened in my case. No overheating and no hard driving. The car has 243k on it. I know my model has a bi-metallic engine but I've never talked to anyone who's gasket just wore out. Usually the engine overheated or they tried to modify the turbo and not the engine. This leads me to my second question.

Is there anything in the construction of the volvo temperature gauge that would lend it to read normal when in fact the engine is hot? I've read the FAQ's regarding headgaskets, but does anyone have any suggestions before I start? This will be my first headgasket repair. With 243k do I need to have the head gone completely through or can I just replace the gaskets, have the valves ground and valve seals replaced? I'm on a student budget and will probably sell the car in the september before I leave for my teaching position abroad. I just read the post about dumping money into our cars and all I could do is shake my head and smile. and wince. Thanks,

J. Studer

Since there wasn't any overheating make sure you do a leak down test to check that the valves are closing properly before doing the gasket. 90% of the time a bad gasket will polute the water or oil.

I have not checked my compression ratio - yet. It just does not seem to have the power that it should, though.

I do wonder:

Did your 740 run hot/overheat in the past?

If your gasket is worn out - where do the leaking gases go? I would have thought they would escape into the coolant area - thus causing an expansion in that area - maybe a bulged - tight rad hose ?? I think I am wrong in this - just need educatin' !

I had an overheat on my 745T- and was leaking coolant through the gasket - Bar's Leak stopped that - but I do wonder if it may have also done a number on my ratios.

I love to learn - all input appreciated!

Andrew in AL


--
'91 940T (198K) , '94 940T (145K) , '92 745T (170K)

Yes, a head gasket can just ware out. It is caused by the difference thermal expansion coeficients for cast iron, the block, and Alumium,the Head.

It is possible that you could install a new gsket and rebolt the head down and have it last till fall, however that is a lot of work to go through and not check the block for warpage and have a machine shop look the head over. Gotta love that student budget. (I am on a parent budget -- Two in College)

If you take the short route, I hope when you sell the car in the fall, you set a budget price for the next student. They may have to go to a shop for repairs if and when it fails.

Congrats on the teaching position abroad. How exciting. Where will you be going?

Good luck.

Dan

I'll be in Lourdes within the Toulouse acadamie in the very southwestern part of France halfway between the Atlantic and the Med. sea. Thanks for the info.

J. Studer

Expect to break an exhaust stud and be relieved if you don't.

Take care,
John H from Downunder

craaaaaaaaaaaaaapppppp.