Q: Overheats when heater is on, heater blows cold air.

asked by on November 12, 2016

I just had the heater core bypass hose assembly replaced two weeks ago due to a very bad leak. Car was running fine after the repair, no temp problems, until I turned the heater on today. Within five minutes the temp gauge was almost all the way up while the heater was still blowing cold. The heater used to work great before the repair, save for a slight coolant smell when turned on. Now it blows cold while the motor overheats! That's the opposite of what I need!

My car has 233000 miles.
My car has an automatic transmission.

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