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!

[cary]

I'm just finishing up the same kind of thing on my son's 2002 A6 2.7t. Might be the same deal. We had the same low pressure leak that lost about a pint a month. I was thinking it was a leaking heater hose because it had no liquid hitting the ground. He's about ready to head back to Eugene so I wanted to get it fixed.

Spent a whole day looking. Finally bought a dye pack. Drove it for a couple days. Again I spent hours on the lift digging around. Nothing.

Then for some reason I look under the big Y-pipe of the air intake. There's my yellow dye. Come to find out the 2.7 has an auxiliary electric water pump. I assume either for the heater or the turbo cooling.
The pump casing was leaking. Kind of a cheesy looking little pump.

Had to tear the entire intake system off. 29 electrical connectors to unhook to get it off. Changed the thermostat while was in there. Kind of in there. You have to literally take the entire front of the car off to do that.

Don't know if the A4 has the same thing? Just a thought.

Bad news this is keeping me from finishing up my engine rebuild and getting one of my 914's on the road.
I'm moving from the Audi to my daughters Escort that just dropped a valve seat. That is one horrible noise. I'm just glad it dropped after being parked. Hopefully the cylinder walls are still good. Will probably be doing a rebuilt head and one new piston and connecting rod.
Then hopefully dad can get back to playing with his toys.

[jk76.914]

Then for some reason I look under the big Y-pipe of the air intake. There's my yellow dye. Come to find out the 2.7 has an auxiliary electric water pump. I assume either for the heater or the turbo cooling.
The pump casing was leaking. Kind of a cheesy looking little pump.

I think that auxiliary pump is 2.7 turbo only, and it's to keep the coolant circulating after you turn the engine off hot. I also have an A6 4.2 and it has no aux pump.

Jim