Water from the radiator is going to the expansion tank which then overflows causing engine to overheat.

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Water from radiator is going into expansion tank which then overflows causing car to overheat. Heaters inside car not working.

My car has 111000 miles.
My car has an automatic transmission.

Hi there. There could be three things that could be causing your engine to overheat and the heater to not work.

  • (1) The thermostat could be stuck shut or causing the cooling system to not flow making the engine overheat and the heater not get any flowing coolant
  • (2) The water pump could have failed or have sludge on it causing the coolant to not cycle making the engine overheat and the heater to not get any flowing coolant.
  • (3) One or both head gaskets could have burned causing the engine to leak coolant into the combustion chamber making the engine overheat and the cooling system to boil over with exhaust gases entering the cooling system.

If you have checked all three areas and you are unable to locate the issue of why the engine is overheating and why the heater is not blowing warm, then I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your overheating issue.

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