Reasons Why Your Car Heater is Blowing Cool Air

Common car heater problems explained

Car issues can make people scratch their heads. If your car heater is suddenly blowing out cold air instead of heat in the middle of a bitterly cold winter, you have a good reason to be frustrated. Unreliable car heaters can make the cold winter months practically unbearable.

Several things can potentially go wrong with automotive heaters because, much like a home heating system, there are many components working together to heat your car. If one or more of these issues is present, your vehicle may blow out cool air rather than heat:

• Not enough coolant in the engine
• Problems with the heater core
• Clogged or broken heating controls
• Dysfunctional thermostats
• Water leaks

Let’s take a look at each of these issues more in-depth…

Reason #1: Not Enough Coolant

Your car uses coolant – usually made up of 50% antifreeze and 50% water – to cool your engine down, especially during the hot months of summer. During the winter when you crank up your heat, the coolant is brought over from the engine to the heater core that then blows warm air into your car.

It can feel cool for the first few minutes because the engine has to warm up in order for the coolant to heat up and provide heat to your interior. If cool air continues to blow out, the first thing you should check is your coolant level. When your car is low on coolant, it won’t be able to send any to the heater core to create warm air.

Reason #2: Problems with Heater Core

Car heater problems are also frequently associated with heater core difficulties: coolant may not be traveling through the heater core properly, the air from the blower motor is not reaching it or there’s a clog in the small tubing of the heater core.

Heater cores, in a nutshell, are cooling system parts that resemble compact radiators. A heater core is made up of brass or aluminum tubing that carries the hot coolant in and out, along with fans that disperse the heat released by the coolant. A heater core is responsible for a vehicle’s defrosting and heating actions. Heater cores are typically situated directly in the back of dashboards.

If your car is not blowing warm air into the cabin and the coolant level is fine, then you could have an issue with your heater core. If you suspect that something is amiss with your car’s heater core, watch for these signs:

• Fog inside of your car
• A fruity, sweet-smelling odor
• Your car using coolant very quickly
• The engine overheating

Reason #3: Broken or Clogged Heater Controls

Sometimes after using the control buttons for several years, they can get gummed up and stop working. If the coolant levels are fine and there doesn’t seem to be a problem with your heater core, you may need to replace some of the control buttons or your heater control valve. The heater control valve is underneath your hood and acts as the switch that turns the heat on and off. If that piece is not working right, your car could get stuck blowing cool air into the cabin.

Reason #4: Dysfunctional Thermostat

If you notice that your thermostat gauge stays on the “C” even after the engine has time to heat up, you may have a broken thermostat. If the thermostat can’t signal to the car that the engine is warm, the coolant won’t be sent over to provide heat to your heater core and the air will stay cool. Thermostats are a relatively easy and inexpensive fix, so installing a new one can get your heater working again quickly.

Reason #5: Water Leaks

The last common problem with car heaters is a water leak. There are many different places leaks can surface, so be sure to check your hoses, radiator and water pump for damage. If any of these three are leaking, your car heater won’t work properly.

An effective heating system can make for a much more enjoyable winter. If you notice any of these issues or can’t get heat to blow out of your vents, contact a reputable local auto repair shop to look at your heating system. It’s important to address problems with car heaters as soon as possible. If you ignore the problem, it may cause a bigger and more costly issue down the road.