I have an issue with my 1988 volvo 240dl. The car itself drives perfectly fine all day all the time except whenever I turn on the ac then the car start to overheat according to the indicator. I have flushed the radiator, filled with new coolant, and changed the thermostat. What else should I check or would else could be wrong. Is it most likely the radiator because the car drives really cool without the ac. The indicator is towards the bottom. What do you guys think.

 

the temp indicator SHOULD be in the middle under normal driving conditions with or without the A/C on.The engine isn't overheating unless the needle goes all the way up to the top. if its much below dead center, your thermostat is installed wrong, or opening too soon.

is your mechanical fan clutch working? if this car has an electric fan, it should come on when the AC is turned on (I'm not sure if an 88 has this or not).

 

Thanks for the suggestions, I will see about the fan clutch.