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Q: Car blows cold air

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Car blows cold air.. it blows a little warm air when fanot is turn on low but blows straight cold air when turn on high.. coolant is full. Doesn't leak when driving but when its parks for a couple hours it starts leaking a little. What could be wrong.. I changed my water pump a couple months back. And my oil is good.. please help

My car has 200000 miles.
My car has an automatic transmission.

Hi There, You may have a clogged heater core that may be prohibiting the outer linings of the heater core to get hot. As you know, the heater core is a series of tubes that the coolant runs through that generates the heat from the warm coolant after circulating through the motor. These tubes can occasionally develop a buildup on the inner walls such that when the heater core is "flushed" this buildup on the inner walls of the lines remains and still allows the coolant to flow through the heater core. It is important to note that when the heater core is "flushed" it is possible to get good flow through the heater core while the inside walls of the heater core remain caked with buildup. As a result, the buildup on the inner walls prevents the temperature from rising to its capability due to the insulating effect of this buildup on the inner walls which will prevent the necessary heat transfer to properly heat the inside of the car. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your heater core.

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