Your Car's Heater & Thermostat: A Hot Topic

Your cars heating system is a simple one. Hot water from the engine is routed to a miniature radiator which is buried under the dash. The water circulates through this little radiator and returns to the engine again. But the story doesn't end here. That little radiator is positioned in a box and surrounded by other components that allow you to direct the warm air to where it is needed. Be that the windshield, vents or floor area. Cold air is pulled in by the blower fan motor, goes through the radiator and picks up the heat. After this is done there are routing doors that open and close at your direction and thus route the air to where you want it.

But suppose you find you have no heat one day...what to do? Look to determine if the engine coolant is at an adequate level. If that's ok, determine if the temp gauge is reporting an under ideal temp. If it is..or if it seems to take forever to get up to running temp, the culprit is the thermostat.

Thermostats can be tricky beasts. They do wear out over time and yours may have just given up the ghost. They are designed in such a way as to open or close in response to varying levels of heat. As the engine grows hot the thermostat will open allowing water to pass on to the radiator for cooling. The thermostat is constantly adjusting to the heat and eventually wears out..usually in the open position...thus, allowing water to pass through all the time...and your engine has a hard time reaching full operating temperature without this "water brake" working. And this is bad for more than one reason, not only do you have low heat coming in to the vehicle interior, but the engine itself will not run at full efficiency unless it reaches proper operating temperature. This can result in poor fuel mileage. And lets not forget another primary reason we need that heat in the vehicle, visibility. That defroster can break the ice of winter, and clear the fog from the glass surfaces in your car.