Hello folks! Did you get any further forward with this A8Chick?
I have the same problem.
My 2006 3.0TDI A8 is rather slow to warm up, and never seems to get to 90˚c in fact it seems happier at 60-70˚c.
I replaced the thermostat with a genuine one as I know these are known to stick open, no change.
Next I replaced the G62 coolant temp sensor to no avail.
The Webasto is working fine and I am manually turning it on, but still running cool.
The heaters in the car get warm but not hot like my old passat which suggests it really isn't getting warm, but could be a red herring.
Any tips? TIA.
