A3 Cooling Down Whilst Driving

[Kurtz]

Hi all. I've been lurking for a while.

My 2000 A3 1.8T is also playing up w.r.t cooling.
I've had the car from new. It used to heat up to 90 within a couple of miles, then stay there regardless, winter or summer, driven hard or not.
Now the thing takes ages to get to 90, if ever. Driven hard the thing drops to 70 degrees or so, then takes a while to heat up again.

Last year I had the timing belts changed (but not the water pump). Audi also changed the temp sender as it would flip 0 to 90 to 0 and back again.

I've changed the temp sender this time. Simple job really. I'm not paying Audi £100 to balls it up like they did last time. But the problem persists.

Anyone know how many temp senders or thermostats there are in the system and where they might be?

I guess I'm saying I'd be interested to know if you find a solution.

[Andreas76]

Mine was doing it too, and you can imagine my surprise, as the temperatures in Greece this time of year are 40 degrees! The heat sensor in the A3 radiator is placed inside the plastic ball where you add coolant from. Because it is located at the top, if a small amount of water is missing from the ball ie a half inch below the minimum line, then the indicator will give a wrong reading. check your system for minor leaks

[RickT]

Sounds like the thermostat to me... as longs as its not going over 90'c it will be ok...

the thermostat controls when the fan comes on also... so if the thermostat is playing up the fan may be coming on early which it turn is still running while you are driving so the air from outside and the fan blasting it will make it drop.... (you can always hear the fan from inside)
so the fan could be working overtime and actually keeping it cool..... however the ideal running temp is 90'c -

Which all components are set to be… it wont damage anything.. However could reduce fuel mpg slightly as not running efficiently??

Cheers