Q: Overheating only after driving on highway for while and the driver side heater won't work.

asked by on December 26, 2016

I have replaced thermostat, radiator cap and ECT. Hoses look good. Fans work. No visible external leak. Drives fine around town all day or days. Then get on interstate and exit some 15 mins later and notice an overheat and decrease in heater temp. I do hear bubbling and gurgling in overflow resivoir. But i have bled the air out now multiple times. I feel like i can never get all air out. But i have done it properly. When i squeeze hose that leaves radaitor and goes to thermostat housing and the hose doesn't feel completely full of fluid more steam.. Could be in my head. Recently passenger door got hit and now i hear clicking noise under hood and only passenger side heater will work.. not driver side. Idk if this did anything but i did feel like it was working before, but im probably wrong. After i get off interstate and let cool i can drive home going 45 just fine with working heater. Last drive is when driver side heater stopped. I need help

My car has 112000 miles.
My car has an automatic transmission.

Hi there. The radiator is plugged up on your vehicle. A plugged radiator will allow the engine to operate normally in town and on surface streets, but when driving at highway speeds with the engine running at a higher speed all the time, then the radiator cannot cycle the fluid fast enough and causes the engine to overheat. This also slows the fluid down to the heater core making the heater not function correctly. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your cooling system before replacing any parts.

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