I recently bough a 1985 Audi Coupe GT with 200,000 miles on it. Paid $400. Reason for it being cheap is becuase the guy told me that it needed a new water pump and battery.. Well I got those 2 things fixed... but the car keep on over heating right? the freaking engine gets sooo hot after a short period of time. I got a new thermostate, put it in, nothing, same problem. The h2o alert light goes on constantly in the car... Also there is pressure building up in the colent tank... thats obviously not normal... its steaming up and i leave the knob a little loose to let the pressure out. What could be the problem??