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Q: Changed thermostat, how long must car run to test for heat

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Car did not have heat,I changed thermostat. What is next thing to check or must car run for certain amount of time to check for heat to work

My car has 100000 miles.
My car has an automatic transmission.

Typically, depending on how cold the weather is the car will need to run for at least 5-10 minutes in order to reach normal operating temperatures which will begin to generate heat. You may also want to check the heater core to be sure it is not leaking and that is is circulating coolant properly. The [heater core]((https://www.yourmechanic.com/services/heater-is-not-working-inspection) circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. I would suggest having an expert from YourMechanic come to your location to diagnose your heating system.

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