Norbert

Hi all,

I have a european 1989 200 20VT Quattro.
I noticed recently that when cruising on highway or in the city without stop and go traffic the coolant temperature goes down from 90C to 75-80C.
(the outside temperature is quite low here right now -5,-10C).
The temperature gauge is ok, the sender is new and also working fine, the thermostat is also new and fine, the coolant have also been replaced.
The car is running fine, there is no problem with it.
Is this normal that it goes down instead of keeping it at 90C?

Is it possible that this lower 80C coolant temperature can increase fuel consumption?

Thanks in advance!
Cheers!
Norbert

V8QinNJ

No it is not "normal". Yes it can cause increased fuel consumption.

The T-stat should react to the temp. of the coolant and open and close based on it's temp, not the metal around it. If it's not than its not working properly.. or is getting stuck at a point in its open/close span.

The increase in fuel is do to the change in temp. The ECU "sees" the car as cold and goes back into closed loop.. adding more fuel to the mix to get it to heat back up.. (just like a cold start in the morning).

yodasfro

you want the 87C thermostat.

audiqv8

Take a piece of cardboard and partialy block off the radiator and see if this help