2000 A-6 Bi-Turbo
How can I tell if I have a blown head gasket? What are symptoms?
Car runs great, no water mixed in oil when checking dipstick.
Looses water from cooling system and cant seem to locate a leak or water on ground.
Someone suggested head gasket may be blown and engine is burning off/evaporating the water.
No signs of anything coming out of tailpipe.
Does anyone know how I can eliminate the head gasket as a possible source of the problem?
Thank you in advance
Kurt

 

One cool trick I learned that's pretty accurate it to do what's called a "sizzle test" (Ghetto name, I know). Basically, you drain a small amount of oil from the crank case - maybe about an ounce or two - and you pour that on to a hot surface, like on an old frying pan. Just make sure the surface isn't too hot because it will instantly go up in flames then.

Basically, if you only see smoke, then you know you don't have coolant in with the water. If the oil bubbles while it's on the hot surface, more than likely you're looking at a head gasket issue or some other issue in which lots of moisture is entering the crank case.

Next, I would then do a compression test on all cylinders (Both a wet and dry test) to see what's going on, and if you have loss of compression on a cylinder or cylinders a leak down test after will better steer you in the right direction so you're not just throwing parts at it.

Do you have any other service info of the 2.7T? Has the water pump and timing belt been changed recently? Have you checked to ensure there's no air in the system preventing proper flow?

 

I recently heard of the sizzle test in the last week and saw it demonstrated on a video; pretty cool test.

My water pump, timing belts, thermostat, etc were all recently replaced a month ago and I had the water leak problem before and after.
I am going to have someone do the compression and leakdown tests but it seems from what I have read on line that it is likely the head gasket. If it is, then I guess the next question is what is the underlying problem that caused the gasket to fail.
Also I assume that the repair is cost prohibitive on a car with 181 thousand miles and maybe it is time to get rid of it.
I am adding water daily to the expnasion taqnk and I dont see water on the ground (if there were a leak) and I also don't see white smoke coming from tailpipe, or water in the oil.
Unfortunately the body and interior and everything else seem to be in good working order.
Kurt

 

Another thing I forgot to mention to check for on the 2.7T is the after run pump. This is in the middle of the "V" of the engine and will come on after the car has been running and a certain temperature threshold has been met. These pumps are common causes of weird leaks. It might also be possible that the pump isn't running when it should and it allows the coolant to boil/evaporate when the car isn't running and will present itself as a phantom coolant leak. Internal parts of an engine are the hottest right after the car is shut off.

Basically, the 2.7T's coolant system is fairly complex when compared to say, a Camry or Altima. Fun to drive, not fun the maintain.

 

The after run pump appears to be working because the fan runs sometimes after I turn off the engine.
We've had a few Audis and currently have 2 and I've learned that once the new car warranty ends, maintenance costs can be quite high; higher than my Benz which I thought was odd as usually Mercedes extracts their share of blood from my wallet.

 

The fan in front of the condenser should run when the after run pump is running, however this doesn't guarantee that the after run pump is functioning correctly.

The pump isn't the easiest to diagnose if it's on its way out. I don't think VAG com offers an output test to check the functionality of the pump. My best guess would be to apply 12v directly to the pump, but at that point you've already done an hour's worth of work to gain access to the pump. If it's not a head gasket issue by the absence of coolant in the oil, and you don't see it leaking out upon doing a pressure test, then I would start to suspect something is going on with the after run system. Heck, the coolant could even be leaking out from the after run pump and evaporating and you just don't see it because it's so far down in there.

I'll agree with you on Audis being very temperamental and at times down right difficult to maintain, especially the 2.7T. I also have a BMW M6 and I've had to do very little to it over the course of the last 3 years that I've owned it. I'm not saying it'll be a walk in the park working on it when it comes time to dive in and fix the first major thing with it, but at this point the E63 engine has been rock solid.

 

Audis would be easier to own without a wife looking over the shoulder and questioning "Why are you spending more money on this car; just trade it" but I get attached to my vehicles and don't know when to let go.
Also, I am up there in years and more familiar with domestic models and repairs, than European vehicles. A little hard to teach an old dog new tricks sometimes,,

 

Well, you're in for quite the surprise and adventure then if you're used to domestics. LOL! Patience and a level head are the two best tools necessary to work on these cars. Then followed by your basic metric sockect and torx bits.

Keep us posted, the 2.7T isn't the easiest to work on, and they're a dying breed so there aren't many of us around who know the quirks of the engine.