Why Is My Car Heat Not Working? As we head into winter, a malfunctioning car heater is an uncomfortable drive. If you're wondering why your car heat isn't working, here are some common causes. Check your car coolant level. If your car does not have enough coolant or anti-freeze, you will have a chilly ride. Addressing leaks promptly also keeps your engine running smoothly. A bad thermostat can also cause a lack of heat. Replace a stuck thermostat to allow proper coolant flow. It is an easy fix that keeps your car's heating system efficient. Your car also has a heater core. The heater core looks like a radiator. A clogged or leaking heater core reduces heat output. If you notice a sweet smell, it could be a sign of a bad heater core. Air pockets in the cooling system also disrupt heat circulation. Bleeding the cooling system eliminates air pockets and corrects circulation. The blower motor in your car moves air efficiently. A blown fuse, faulty resistor, or worn-out blower ... read more