Help identifying possible coolant leak
 

So I suspect I have a coolant leak. This is a new car for me, but let me give you a little background.

Before I bought it the car got a full fluid flush including engine oil and coolant. I wrote that off as it was probably burping since it was just flushed. I drove it for a few hundred miles and noticed the coolant was low so I topped it off. I then soon after did a TB/WP service with some help from local 944 guys.

We flushed the coolant again, refilled and bled. About 500 miles later, the coolant is low at the min line. But no drops or signs of leaking anywhere, belly pan is dry, and i pressure tested the system and it seemed to be fine.

It may be irrational, but if everything checks out, I fear a head gasket. But since everything is so new I can't tell if oil is getting into the coolant. It does look like there is a slight oily residue in the coolant (Picture below).

What do you guys think? Am I paranoid? Or am I on to something.

https://farm4.staticflickr.com/3882/...acb88a75_o.jpg


I also found my passenger foot well wet, but this is due to a long time issue with the battery tray.

I think you're onto something, that looks like an oil/water mixture to me.

Yeah it is hard to tell because all the fluid is so new. Also I forgot to mention that the car sat for about 9 years (driven only a few times between then and now) before I bought it. So I'm hoping it might be some gross residue leftover in the cooling system.

Is the oil normal? The coolant is either in the oil, entering the cylinders, or leaking out somewhere else.

I've never used one myself, but those head gasket tester kits may be worth a shot. They affix to the expansion tank and check for combustion particles in the coolant.

Another thought. I did use a funnel to fill it. Possible residue from that?

The oil looks normal on the dip stick.

I guess the only thing to do now is to keep driving it and see if it gets worse. Man I would be devastated if it was a head gasket! I will look into doing a leakdown test as well. Any other recommendations?

First wipe off the oil on the cap and mouth of the coolant tank. Then top off coolant, and draw a line with a pencil at the coolant level on the coolant tank when cold and car sitting level. Drive and monitor coolant loss at this line after it cools down. If all is tight the coolant should stay at this line indefinitely and the oil won't return.

If it is getting oil in the coolant it could be the oil cooler seals. Not quite as much fun as the head gasket.

Ooo I even have the oil cooler gasket already. That would be nice. Been driving it 2 days with no further loss, but that's only like 20-30 miles

Ok here is another question. It is about when to measure coolant level.

When the car is hot and pressurized it is at the min line. When I release the pressure (still pretty hot it is about 1-2" above the min line.

When cold it was below the min line.

I read that you should fill to min when dead cold. I filled it about half way between min and max. Do you think I'll have some coolant come out of the overflow?

Also I realized when i burped the system, i just pressurized the engine cold. And today I used the heater on full blast to try and open up the heater.

Maybe. Fill it up and see.

paranoid, that coolant looks fine. if you overfill (to max when cold) it will piss out the overflow.

look for condensation droplets in the oil fill neck ( if theres water in the oil and the engine has ran the water will rise to the top and collect. in the and around the yellow cap.

Also check the rad cap rubber seal

Checked that last night. No condensation on the oil cap. rad cap was just replaced.

Notice a sweet smell when you turn the heat on max?

pull the spark plugs . you could be getting coolant into the combustion chamber and burning it off . if this is the case you may not see any oil in the coolant or coolant in the oil .
if you have one very clean plug it could be the explanation of were your losing coolant .

+1 on what 962 said.

Leave 10# of pressure on the cooling system overnight and look for moisture in the cylinders...

My last cooling system leak was where the female bayonet part attached to the overflow tank. A mix of 50/50 dish soap and water found that one.

Bleeding missed air pocket?
 

If you are lucky when you bled the air out during your last coolant change you had a hidden air pocket that just worked it's way out (over your 500 mile drive) to the expansion tank lowering your coolant. Hopefully that is all it is. Good luck.

That black stuff is from combustion gases. After a drive can you hear air escaping from the rad cap? Does the coolant smell a little like fuel?

My guess is you are losing it out of the overflow due to combustion gases leaking through hg into water jacket.