As I mentioned in my other post, my 05 A4 1.8T Q has a failed head gasket. Searching on the internet pretty much returns that over heating is the prime cause.

My question is, can the engine overheat and it never register on the dash? My gauge has never, ever gone past exactly halfway ever since I drove it off the lot 12 months ago.

The other suggestion for HG failure is pre-ignition/detonation. Would that be the same as misfiring? Damn car has misfired since December and the dealer had never ever figured it out. Can the car misfire and you not feel it/know it?

 

Misfiring and overheating are two different issues. When your engine misfires or pre-ignites it can cause higher temperatures in the cylinder chamber warping the aluminum. Its basically a small explosion inside the engine, if its not timed right excess fuel will get into the exhaust and ignite there further increasing the heat to the cylinder head and possibly the cat converter. Your engine can misfire without you noticing it, but not enough to take out a head gasket. If you truely do have a bad gasket then it was caused earlier when your engine was missing really bad. I wouldn't be surprised if they came back and said your cat converter is toast as well. I should also mention that a plugged up cat caused from misfiring, can create a misfire in the engine because its like trying to blow air thru a kinked straw.

ALL of your problems started with bad coil packs, and they most likely know it, so i bet the shop forman is looking at your car now.

 

Dude, I totally agree with you. Thinking back, I bought it with 42K on it, it now has 48500. I have changed the oil twice, and only ever put premium in it. If they even try and say I did this, I will call BS and be highly pissed off.

Guy said he would call me tomorrow with an update, and the car should be ready on Monday or Tuesday. But, we will see.