2000 A6 2.7T overheating

[kf21857 at comcast.net]

Tim:
That seems like the most likely answer to me.  However, I stuck a mechanical temp gauge in place and let the engine idle long enough (30-45 minutes) to reach about 210F.  It seemed to stabilize there.  I quickly popped the original sensor back in place and found it is giving a normal reading.  Maybe enough water circulates at idle by convection to keep it normal.   I am going to test it at highway speed one more time, then start taking stuff apart.  Thanks for the suggestion.  I think it's the water pump or an intermittently sticking thermostat.
Dave

 -------------- Original message ----------------------
From: "Tim Leonard" <nard1 at cablespeed.com>
> Dave,
> The plastic impeller on the water pump has failed/broken causing NO coolant 
> flow. Engine will overheat abruptly. Water pump should be replaced when 
> timing belt is replaced. You did not indicate mileage and perhaps you are 
> already aware that the belt and water pump and thermostat and related 
> parts/fluid must be changed at recommended intervals to prevent the problem 
> you describe. Maintenance is cheaper and more convenient. Also is the same 
> vein; Mobil1 oil and Shell fuel (and others). www.toptiergas.com
> Good Luck
> Tim Leonard
> Audiwerke
> ESCARGO
> Michigan 
>