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Q: The heater isn't working right.

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The heater takes to long to START to get warm. Then it will stay warm for a few seconds. Then gets cold again. I'll turn it back off for a few seconds. Then turn it back on and it will be a little warm for a few seconds then gets cold again. This goes back and forth about 30 minutes and if I'm lucking it will finally stay warm. But sometimes it does take a little longer. Up until about 3 months ago it got warm right away and stayed warm. What part might it be and what can I expect it to cost. Thanks, Candy.

My car has 160000 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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