Asked by: Yassim Ramdas
asked in category: General Last Updated: 24th February, 2020

Why does my car heater only work when Im driving?

As far as the heater not heating up fast in the car, either the engine coolant is not hot enough yet to heat up the car or there is an issue with the heating system or cooling system in the vehicle. If the valve is working correctly, then the thermostat may be sticking open when the engine coolant is cold.

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Similarly, why does my heat stop working when I stop?

Ken Mattson, owner of Len's Automotive in Bellevue, Wash., says a car heater can stop working for a number of reasons, including: A low antifreeze/water level in the radiator due to a leak in the cooling system. A bad thermostat that isn't allowing the engine to properly warm up.

Likewise, why is my car blowing out cold air when the heat is on? Hot coolant from the engine passes through a heater core, which looks and functions a lot like a small radiator, and a blower motor forces air through it. It's also the reason that a plugged heater core, stuck thermostat, or air in the cooling system can all cause a car's heater to blow cold.

Also, why does my car heater not work when idling?

The engine makes very little heat when idling, and if the thermostat does not close, the engine coolant temperature may drop low enough that you'll get no heat from the heater core. If the coolant level is low in some cars, the water pump may not provide any flow to the heater core at idle.

How expensive is it to replace a heater core?

Replacing the heater core can be an expensive job, and usually costs between $564 – $927 for parts and labor. The parts aren't particularly expensive, normally costing $80 – $234, but the location of the heater core means that labor costs tend to be quite high.

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