2000 A6 2.7T overheating

[kf21857 at comcast.net]

It turned out to be a stuck thermostat which was only opening about 3mm instead of the 8mm the Bentley calls for.   Apparently the coolant loss was caused by the overheating, not the other way around.  I will keep an eye on the coolant level but the system is holding pressure several hours after being shut down so I think everything is back to normal.  I replaced the water pump, belts, cam seals, etc etc while I was in there.  Everybody makes fun of Audiworld, but they have some tech articles on line that go into a lot more detail than the Bentley does.  I referred to both of them.
Dave

> > I understand that, but the same symptoms occurred after refilling the
> > expansion tank.  That is how I knew it was down 2 qt.  The system is
> > definitely pressurizing.
> 
> A genie didn't wave a magic wand and have such a large volume of coolant
> magically disappear.  You have a *substantial* leak.
> 
> Find and fix the leak, like everyone has been telling you.  You'll
> probably find a cracked plastic piece, pinhole leak in a hose, or a loose
> hose clamp that only starts to leak once the engine warms up and the
> system begins to pressurize.  If you can't find a leak anywhere, you may
> have a leaking head gasket.
> 
> Also, I don't know if the 2.7TT engine requires a specific purging, but if
> you were down two quarts, you could have air trapped somewhere.  On the
> older cars, the instructions were to park the car on a sharp incline and
> run it with the cap off until the fan cycled on.  I have no idea what the
> process is on newer cars, or even if it's necessary.  It's moot until you
> figure out where the coolant is going, however.