What do you think? Is the headgasket going or not?

Symptoms:

- Very slow coolant leak. Car won't hold pressure at 15PSI on a cooling system test. I do have two very small hose leaks that have been problematic to seal. Car looses maybe 2 cups of coolant on a track day.
- All 4 plugs look normal. No white or steam cleaned plugs
- Compression 1 to 4 is 145/145/140/145
- Leakdown 1 to 4 is 3%/3%/4%/4 to 5%
- Getting small amounts on condensation on filler cap. Nothing on the dipstick.
- Car seems to steam out the tail pipe after warmed up, especially after driven hard. No sweet smell.
- Car can sometimes run on 3 cylinders for a couple moments when started after running hard.

Car has a widefire gasket that was installed about 50k miles ago. Running 15PSI boost.

I'm leaning towards there being some HG problem due to the miss on a hot start after a hard run and the steam from the pipe. I don't know if I'll ever get the coolant leaks fully fixed as it's been hard to get several hoses to perfectly seal.

Thoughts?

 

Sounds like a headgasket to me. Run the car hard under the same conditions which cause the car to run rough on start up. Pull the plugs prior to starting and look down each spark plug hole. You will probably see coolant pooled in one of the cylinders. I had an issue like this on my '87 where it was doing basically the same thing. I did a compression test and it showed up normal aswell. It was only leaking when the car was off, the fire ring on the headgasket had split in half and it was leaking into the cylinder.

 

Steam out of the tailpipe when warm is definately a sign of bad HG.

 

Pressurize the coolant again, with the plugs out...

This is how I found my bad HG, had water leaking into 3 cylinders!

 

John - yeah, i was all about that until i discovered the small leaks elsewhere in my system.

Minho - concur with your read. Steam ain't good.

 

+1 on Johns cooling sys press test.

A compression test (or leakdown) for that matter, aren't very good at diagnosing a small headgasket problem. If a headgasket is breached enough to drop compression significantly, you'd be flowing damn near as much air through your coolant reservoir as your throttle body. OK, exaggeration, but it would be a bunch.

I've seen threads on here that went on for weeks about diagnosing one HG. Just spend the $50 on a combustion gas tester and you'll have enough fluid to to 5 tests.

 

Maybe not ‘failed’ but I would give it a D and make it repeat the class….

Your headgasket is not long for this world – keep in mind that a catastrophic failure can damage a lot of other parts – especially on the track! Right now you might be able to get away with just replacing the gasket.

 

+1, this was my option when I found it.. I CHOSE to rebuild my head, while it was off.. and if I had to make the same decision again I would still have had the head rebuilt, but perhaps my another shop...

Although once it was in for rebuild I was glad I made that decision as 3 of the 8 guides were excessively worn (all 8 replaced), and all 8 seals were shot.. go figure at only 100K miles the head would be shot! At least the valves were still good!

 

No milkshake going on at all? Is changing the headgasket a big job? How many more hours worth of work?

 

Ha....now that's funny! Yeah, I concur and it's coming apart to get a new HG. Thanks everyone for selling me on doing the right thing.

Cherry on the Sunday will be the new K27/6 I'll put in the at the same time!

 

i would do it now before the oil is contaminated and the bearings/rings etc are junk. Maybe do the oil cooler seals while you are in there....