The temperature on my A6 1.8t drops slightly when cruising along on speeds above 45ish, but stays steady at 90 degrees when driving around town. Just changed the temp. sensor since the gauge was all over the place, so it shouldn´t be that. Anyone know why it does this?

 

air flowing through the radiator. normal condition

 

lol you have no fear of low fuel do ya?

 

Hehe.. waited for a comment on that.. I was on my way to the gas stasion..

 

Sure? Never seen this on my other cars tho..

 

The thermostat might be stuck open

 

^^ Ditto.

 

^^ Ditto Ditto

 

For info: A modern car, with a good clean cooling system, will "ride" on the thermostat.

That is it has enough cooling capacity to cool a normally running motor to much lower than it needs to be. When you start the car the thermostat will be closed until the engine gets above operating tempature. At that point it opens and cools the engine below the closing temp on the thermostat. The engine then warms back up and opens the thermotat again. Understand this is due to the "extra capacity" of your cooling system. If you didn't have this capacity, the engine would overheat for any little reason... climbing a hill... a hot day... dirt or rust (corrosion) in the cooling system... you get the idea.

SO... if your engine tempature drops below operating tempatures, during operation, odds are you have a thermostat that does not close all the way. It doesn't need to be stuck "open"... just not seal. I have seen warped seating surfaces and "chunks" stuck in the seal.

With the amount of work required to replace it on my car (your's may be different) I would leave it alone until the next timing belt change... unless I needed heat in the heater!

 

OP I'm curious, I see you're obviously not in the US, but what market do they sell A6's with the 1.8t 20v?