N_Jay

I don't know these engines well enough yet.
Others can probably answer; Does the intake manifold gasket pass any coolant between the head of the manifold? Or doe sit seal off any open coolant passages/spaces in the head?

If yes to either, that is another possibility.

jcman

No coolant pass in the manifold just the pipes under it, hope this helps.

thall6594

Do any of those pipes connect between cylinders 2 and 5 specifically? The shop said they would have to pull the manifold to check the pipes/o-rings, so they didn't do that and just said I have (2) bad head gaskets without confirming. I really don't think both started leaking at the same time, and I can still hold pressure just fine.

N_Jay

But running under the manifold without a connection does not explain antifreeze getting into the combustion chambers. (returning me to a cracked head, or bad head gasket). (Or the rare cracked block)

thall6594

But it holds pressure, doesn't overheat, no cross contamination, and there are no external leaks..

N_Jay

A couple of teaspoons of leakage into a cylinder from a head gasket or cracked head will not reduce pressure enough to measure but will make lots of steam.

thall6594

How can that really be diagnosed then? I haven't seen my car smoke on start up in a month, and before that it did maybe five times.

N_Jay

Run a compression test. If that shows good, you might just have to wait till it gets worse.

bgross88

Well, my compression test came back fine. I talked to a local Indy Audi repair guy. He also thinks it's a cracked head. TBH--I have no idea how that would happen. It just started this a few weeks ago, and I know the car hasn't been overheated. He's seen them crack between the valves(mainly on a 1.8, I think he said). He wasn't sure if the heads are/were a problem on the 3.0's.

He did suggest trying radiator aluminum powder. Since there no glue/bonding agent, he said if there is a very minor crack, it might work and it won't gum up the engine. Haven't decided on that yet....

N_Jay

Worth a try, and/or just live with it watching for secondary issues, and start saving up to build the engine of your dreams.