I own a 1999 tdi and I am having some temperature problems with it. It wont warm up no matter how far I drive or what strain I put the engine under the gauge still stays on 60 and doesnt move, the fan has also never come on. I have replaced the thermostat with a proper Audi one and sealed it properly etc and it made no difference. I dont think it is the temperature sender as the water temperature in the expansion bottle is below 60 degrees and you can wiggle your finger in there fine even after a long drive, it almost seems as if the engine is over cooling? The heaters do warm up a bit and will warm the cab but they are nowhere near as warm as they were on the S3 I owned previously. Pretty stuck with this and dont know where to go next it still delivers good economy at ~47mpg but I want it fixed! Any help please?!