I have a 1999 Audi A3, 1.6 The car started to overheat yesterday and today is misfiring (engine got very wet yesterday when I was changing the thermostat/flushing the coolant, so i dont know if that could cause the mis fire). There is no white smoke coming out of the exhaust and there is no sign of oil in the coolant and it doesnt seem to be mayo'ish under the oil cap. The internal heater in the car is not blowing any warm air at any temperature whatsoever, only cold air. I have changed the thermostat and flushed the coolant and still the problem is there. The fan kicks in, but only when it is starting to overheat! The first time it started to overheat, I wound the windows down and blasted the heating, yet no heat came out! The heating has been a problem for a couple of weeks before the misfire and has gradually got worse... Any ideas or advice very welcome! i hope it isnt the head gasket! Could it be an airlock or the water pump ?