Hi, Got a new waterpump and cambelt fitted when I got the A3 a few weeks ago. Temp gauge erratic, changed to audi thermostat (ran it for at least twenty minutes with only 3lt of coolant, didn't figure it out until I moved car and it obviously got rid of air lock and low water came on, I don't think I've buggered it though). Changed sensor tonight and it sits solid at 90 now. Sat for 20 mins and fan does not kick in. Just have water in system now but would like to make sure the whole thing works and that fan kicks in before I refill with coolant. How the hell do you get it hot enough?