Is my Audi A4 head cracked? What to do?, Last update. 10/13. Spewing coolant. Options

[jk76.914]

I may be in a pickle. My daughter's 2004 Audi A4 1.8T, 105,000 miles, was using some coolant. I looked and looked and looked, there was no evidence of a leak. It used about a pint every 500-1000 miles, so I thought there should be some visible sign, but no. There's no symptom at all. Nothing wet, driveway dry, no smoke, starts good, runs fine....

But then yesterday, after topping it off again, I changed the plugs. The threads on the #4 plug were wet. The other three not. I'm guessing a crack from the plug to the water jacket somehow, and it probably opens up at temperature, seeping coolant into the combustion chamber.

What do you guy's think? The wet threads seem to confirm the diagnosis... Any other ideas? Anybody know if these things are prone to cracking?

Any danger in trying a Bars Leaks sealant? They're pretty well regarded, I think, and they have four products for cracks, head gaskets, etc... I'm thinking of trying the mildest first.

She commutes from Boston to Rhode Island daily, putting about 400 miles on the car every week.

Here's a picture of the 5 valve combustion chamber I found on line. Lots of opportunities here for cracks... Help!

[Dr Evil]

There is no way that water could have gotten into the hole from the outside, right?

[jk76.914]

There is no way that water could have gotten into the hole from the outside, right?

I don't think so. The plug bore, coil, etc is dry. There are no hoses anywhere in the area. And those threads are wet below the gasket. That would have been nice...