Q: Heater and coolant not working

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The heater blows out cold air no matter how long I wait and keep it on. Also the engine stays mostly hot. It switches from being in the middle to H the whole time I am driving with a good amount of coolant. I think the two problems are connected. What needs to be fixed or replaced for these two problems? Thanks.

My car has 110000 miles.
My car has an automatic transmission.

Engine coolant is not only responsible for cooling the engine, it provides heat for the interior as well. Coolant flows from the engine into the heater core, which is located inside the car behind the dash. If coolant is not flowing properly within the cooling system, the heater core will not have hot coolant flowing through it to give you heat for the interior.

Possible causes can be a thermostat that is not opening properly, a water pump that is not circulating the coolant properly, or a clog in the cooling system. These will also make the engine run hot or overheat. Continued driving with the vehicle running hotter than designed, can cause internal damage to the engine as well as cause damage to external plastic and rubber components such as sensors, vacuum hoses, etc. Have a certified technician diagnose the running hot condition as soon as possible before engine damage occurs.

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