I have a 02 Audi A4 1.8T Quattro and the problem I'm having is that if I leave the car on and at a standstill, the car will get super hot (til overheats if I let it) and it goes through ant-freeze/coolant like no other. Along the same lines, when I'm in stop in go traffic, the A/C will get hot if I'm waiting in traffic. The temperature gauge on my dash was working all the time and stayed at halfway once the car was warmed up, but now with it being summertime and 80-90 degrees farenheit outside, the temp. gauge doesn't move (stays at "C" cold). However, in the morning when it's still cool outside, the temperature gauge on dash does work and stops at halfway when warmed up. I recently had my car in the shop for a timing belt/water pump maintaneance replacement and the Audi mechanics identified that there was an issue w/ the coolant system, but I don't think (atleast at that point) a VAG would produce any codes for this issue. I need to get this fix as it's summertime where I'm at and during the day my dash temperature got up to 95 degrees! Cold starts are a little rough currently too, but I'm not sure if that's related. I'm wondering if this issue sounds like a sensor gone bad, thermostat issue, or something else. Also, I'm wondering if replacing the thermostat is expensive (for the part and labor). Thanks for the reply!!

 

bump...

 

bump it again...

 

I'm having the same issues...replaced thermostat..just as expensive as water pump as they have to take the front off as was done when you replaced the watter pump...mine still heats up but not as bad...now I wonder if I need a water pump???

 

Well, I didn't have my water pump replace again, but they said I needed a new cooling fan module as some of my fans weren't turning on. So I would make sure all your fans are going. Now, when you turn your car off, you should be able to hear your fans still on and turning off. Mine are really loud now when I turn my car off.

Also, I needed a new coolant temp sensor. This is why my temperature sensor on the dash wasn't reading halfway even when the car was warmed up.

The rough cold starts were due to one of the teeth on one of my plugs that your coils plug into was pushed back (4 teeth per coil) and thus it was ruining the coils and it wasn't getting a good electrical connection.