Head gasket blown?

[edfishjr]

Opinions, please!

Well-cared for 1989 944 (2.7 liter) with 130K miles, all stock engine, just put back on the road after being up for 2 years.

Car is running and I've been auto-crossing it. Yesterday a buddy helped me do compression and leak down tests.

Numbers were good.
Compression 200, 200, 205, 205.
Leakdown numbers were 4% to 9%, the worst being #2.

As I'm putting the plugs back in my buddy pulls out a borescope and we put it down #1. I see something strange: a drop of fluid, what looks like coolant, running down the cylinder wall. Piston and wall look good, BTW. My buddy thinks it might be oil, but it looks too thin to me.

When I back the car up we have a lot of coolant on the floor... maybe 6 or 8 ounces. I leave the car running for a while but no more drips out. My garage floor at home is dry as a bone, but I had some coolant overflow at one autocross.

Gotta be the 80psi leak-down air pressure forcing coolant out the over-flow through a slightly blown head gasket, right? Any other possibilities?

[9FF]

Tell-tale sign of a bad head gasket would be your coolant bubbling while you were performing the leakdown. If that wasn’t happening I wouldn’t worry about it.

[edfishjr]

Originally Posted by 9FF

Tell-tale sign of a bad head gasket would be your coolant bubbling while you were performing the leakdown. If that wasn’t happening I wouldn’t worry about it.

We did not see bubbling. Coolant level is definitely low this morning.

[9FF]

Originally Posted by edfishjr

We did not see bubbling. Coolant level is definitely low this morning.

Top up coolant and run it, check again for any bubbling in the coolant with the cap off and look for any white smoke at the tailpipe. If you’re not getting either you likely just had a minor coolant leak either from a loose clamp or from the overflow.

[edfishjr]

Originally Posted by 9FF

Top up coolant and run it, check again for any bubbling in the coolant with the cap off and look for any white smoke at the tailpipe. If you’re not getting either you likely just had a minor coolant leak either from a loose clamp or from the overflow.

Thanks.

The engine was hot so we did not have the cap off when testing yesterday. We listened but could not hear any air noises at any time.

[9FF]

Originally Posted by edfishjr

Thanks.

The engine was hot so we did not have the cap off when testing yesterday. We listened but could not hear any air noises at any time.

In all honesty a failing head gasket is almost impossible to diagnose. Even if everything checks out it could well be weak in an area that may cause imminent failure.

Btw whenever I do a leakdown, as well as removing the coolant tank cap and looking for bubbles hinting at a head gasket failure, i also listen for air leaking in three areas. I remove the dipstick and listen down the tube which would point to rings. I open the throttle plate and listen for air leaks there which would hint at intake valves. An ear on the tailpipe can identify hissing that would point to exhaust valves. This likely won’t help you but it may help others searching here as I know a lot of folk simply do a leakdown for the numbers without identifying the actual cause.

[edfishjr]

Originally Posted by 9FF

In all honesty a failing head gasket is almost impossible to diagnose. Even if everything checks out it could well be weak in an area that may cause imminent failure.

Btw whenever I do a leakdown, as well as removing the coolant tank cap and looking for bubbles hinting at a head gasket failure, i also listen for air leaking in three areas. I remove the dipstick and listen down the tube which would point to rings. I open the throttle plate and listen for air leaks there which would hint at intake valves. An ear on the tailpipe can identify hissing that would point to exhaust valves. This likely won’t help you but it may help others searching here as I know a lot of folk simply do a leakdown for the numbers without identifying the actual cause.

We did all that except remove the tank cap. As well as our ears we also used a mechanic's stethoscope to try and hear any hissing. Nothing could be heard. However, it was clear that a little bit of air was coming out of the dipstick hole. Covering it with your thumb did not create any pressure buildup, however.

I started it up from cold this morning with the tank cap off, looking for bubbles and listening for gurgles. When the heater valve opened up I got two or three bubbles but nothing more.

I'm going to watch it closely.

[DannoXYZ]

Headgasket failures typically do not spill any coolant externally. Usually it's sucked into cylinder and disappears out tailpipe.

Look under gas cap for chocolate milkshake. Also look at oil.

[OK-944]

Ugh! That's more like a mocha shake!

Another indication that something could be up is excessive pressure/bulging in the top coolant hose (coming off of the water neck).

[edfishjr]

Originally Posted by OK-944

Ugh! That's more like a mocha shake!

Another indication that something could be up is excessive pressure/bulging in the top coolant hose (coming off of the water neck).

Thanks. So far no milkshake, no bulging hose.