A friends '92 legacy was overheating and blew a hole in the radiator.

I determined the head gasket was leaking because air was pushing a lot of water into the overflow and the engine overheated quickly.

A Compression test showed all cyls (except #4, drivers side rear, which was 80-90) at 140.

 

After replacing the head gasket on only the drivers side, I now have 140 psi compression on all cyls., but still have air pushing coolant into the reservoir and engine:Flame: overheating.

Any suggestions on what to do next? It looks like I still have a head gasket leak even though compression has risen on the #4 cyl.

 

Jim

Did you have the heads machined?

Did you clean the block down to bare metal?

Did you follow the head bolt tightening procedure to a T, as if your very life depended on it?

If you can answer NO to any of these there is a good chance the gaskets did not seal properly.

 

Air in the system can play tricks on you after a head gasket job. Make sure you have bled all the air out of the cooling system.

 

What brand of head gaskets did you use?

Your heads are probably not true. They are likely warped. Take em off and send em to a machine shop.

And do them both.

Did you burp the coolant?

 

heads etc don't normally warp on these Subaru engines.

your compression is fine maybe 150 would be better on all but not a worry there.

 

I would say burp the coolant like said, and you should be okay.

Edited December 5, 201114 yr by bheinen74

I DID clean the surfaces very well, and used a dealer supplied gasket.

I did not have the head machined,and also did only the drivers side, so it looks like that is my next step (machine both heads and install new gaskets again).

I had the bleeder cap open and filled the radiator through both the bleeder valve and the radiator cap when the engine was warmed up, but it is still blowing water out of the filler neck when I rev the enging at operating temp.

It sure seems like I have the air out of the system.

If I drive it a bit affter warmup, the reservoir will be filled to the top and the temp guage quickly shoots up towards hot:Flame:

Thanks for the help,

 

Jim

" but it is still blowing water out of the filler neck when I rev the enging at operating temp."

 

Isnt that what is supposed to happen? the cooling system is supposed to be pressurized when it is at operating temp i thought. Close the system up with it full, and open the overflow tank with it running at operating temp and look for air.

perhaps the other head gasket is bad. It is silly to only do one gasket if you have the intake off and the engine looking at you.

Stating the obvious here: check the coolant for exhaust gases. That will let you know.

perhaps the other head gasket is bad. It is silly to only do one gasket if you have the intake off and the engine looking at you.

 

 

I would totally agree. But you know, "one side is good enough for me" is offical Subaru warranty policy. Under warranty, Subaru usually only authorizes head gasket replacement for the side that failed.