Brrrr. It's cold outside. And if your vehicle's heater isn't working, then it's cold inside too. No fun – and potentially dangerous: heat is needed to defrost your windshield. Unlike your house that has one furnace, a vehicle's heating system has several different components, so it takes a trained technician to figure out where the problem is.

Here's how the heater works in most vehicles. Coolant circulates through the engine (it's helping the engine disperse the heat it generates). Some of that heated liquid passes through a smaller radiator called the heater core, which is under your dashboard. A fan blows air through that heater core, and heated air is distributed into your vehicle's passenger cabin. 

As you can see, there are several different possibilities when your vehicle's heating system is not blowing hot air. It could be that heater core needs replacing, and its location can make it very difficult to access.  The blower motor is another possibility; without something pushing the air around, the heat doesn't get to where it needs to be. Or it could be that one of the little doors that open to let in either cool air or heated air is not working properly.

Your vehicle also has a thermostat which essentially blocks coolant from getting to the radiator until the engine has warmed up. If that's not working properly, the engine may take a long time to warm up. Your vehicle may also have a leak in the cooling system, which can affect how much heat can get to the cabin. Those leaks can be something easy to fix, like a leaky hose, or something much more involved, like a bad head gasket in your engine.

If your passenger compartment is not heating up the way it should, it's best to have it evaluated at your NAPA AutoCare Center. First, it's uncomfortable to drive on very cold days without heat. Second, that lack of heat may be telling you that your cooling system has a much more serious problem that could continue to get worse and leave you stranded.



The best advice is to keep your vehicle's cooling system in top shape with regular maintenance, including the proper mix of coolant and water. Your NAPA AutoCare Service Advisor can schedule your recommended cooling system service, making it less likely that you'll find yourself wondering where the heat is on a cold day.