I recently replaced radiator fan, thermostat and CTS (green one) and my engine is still overheating. The primary suspect is the water pump, but I could use a confirmation so I don't replace a good part.
My engine goes to 110°C but then suddenly drops back to 90°C, the engine makes a strange noise while this happens. Also the engine kind of throttles when at 110°C so I don't think the new CTS is broken. I should also say that the hose comming from the thermostat to the radiator is warm but not hot, only gets a little bit warmer when the engine makes that weird should.
My car is Audi A3 2001 1.9TDI ASV Engine.
UPDATE #1: I just drove for about an hour on the highway and I had no overheating problems. Also when I went off the highway and drove through the city at 50km/h no overheating problems. Then I went to the gas station and turned off the car, the temperature was 90°C. Went inside bought some coffee, went back in to my car, turned ignition on without starting the car and the temperature was just above 110°C, how is this possible? I successfully replicated the problem 2 more times, just stopping, turning the car off (temperature at 90°C) and turned ignition on (temperature little above 110°C). I tried the third and fourth time but I could replicate it anymore. I will do more testing tomorrow but this is just weird. Any thoughts?
I got a faulty temperature gauge, car doesn't actually overheat according to live data from OBD scanner.