Skip To Page Content

Why Isn’t My Car Heater Working?

Reasons Why Your Car Heater Isn’t Working and What to Do

It’s getting chilly here in Portland. The last thing anyone wants is to wake up on a cold winter morning, get to their car, turn it on, and find out that the heater isn’t working. Like most automotive issues, there’s no one cause to a malfunctioning car heater. Multiple components work together to provide heat to the car’s interior. While a reputable auto repair shop such as Ken Van Damme’s Automotive can diagnose your car heater problems for you, here are a few possible causes of the issue and what to do about them.

How Your Car’s Heater Works

Your car’s heating system is composed of a heater core and a heater fan, along with other components. The heater core resembles a small radiator, and it circulates the coolant in the same way that your vehicle’s full-sized radiator does. When you turn the heat on in your car, the hot coolant from the engine diverts to the heater core. The heater fan blows air over the core and into the cabin of the vehicle. This explanation is, of course, a simplified explanation of what happens when you turn the heat on in your car, but it’s important to understand when diagnosing car heater problems.

Low Coolant

If the car heater’s fan is working, but it isn’t blowing out any hot air, the cause could be low coolant. Coolant is a mixture of 50% antifreeze and 50% water and works to keep the engine cool. However, when the car’s heater is on, the coolant goes to the heater core and warms the air to be blown into the cabin. If the car is low on coolant, it can’t heat the cabin air in the heater core. The first thing to check when the heater isn’t working is the coolant level.

Contaminated Coolant

In addition to low coolant, contaminated coolant can also affect the efficiency of your car’s heater. If the coolant has any contaminants in it, such as rust particles, it won’t circulate in the heater core properly. If you suspect your vehicle’s coolant is contaminated, take it into your local auto mechanic for diagnosis and repair.

Heater Core Problems

There are a few different heater core issues that could cause problems with the cabin heater in the vehicle. A car’s heater core resembles a small radiator, and it’s responsible for heating and defrosting. If warm air isn’t blowing into the cabin, but it’s not the coolant, the heater core may have an issue. Whether the coolant isn’t traveling through the heater core properly or if there’s some clog in the heater core’s tubing, there are a few signs to watch out for when it comes to the heater core, including:

  • Overheating engine
  • Overuse of coolant
  • A sweet smell in the cabin (could be the coolant leaking)
  • Fog on the inside windows of the car

If you notice any of the above issues, your vehicle’s heater core may have problems, and you’ll need to take the car into Ken Van Damme’s Automotive to have a technician diagnose and fix the problem.

Broken Heater Controls

If nothing seems to be wrong with the heater core and the coolant levels are acceptable, the car may need new heater controls or a new heater control valve. Sometimes, the heater controls in the cabin of the vehicle get stuck after years of use and need replacing. If the heater control valve (under the hood) isn’t working properly, this could be the cause of the cold air in the cabin. If you suspect an issue with your heater control valve, take the car into Ken Van Damme’s Automotive for diagnosis by ASE-certified technicians.

Broken Thermostat

If the vehicle’s thermostat doesn’t work, the car won’t receive any signal that the engine is warm. In this case, the car won’t send the coolant over to the heater core to provide warm air to the cabin. Installing a new thermostat is not usually a pervasive process, so take your car to Ken Van Damme’s Automotive to get it fixed.


If your car is leaking coolant or water, the heater won’t work properly. If none of the above seem to be the issue with the car’s heater, there may be leaks somewhere in the system. The hoses, radiator, and water pumps all need an inspection to eliminate the possibility of leakage.

Malfunctioning Blower Fan

If there’s no issue with the coolant or leaks in the vehicle, the blower fan may be malfunctioning. The tell-tale sign of a malfunctioning blower fan is the absence of any air blowing in the vehicle’s cabin. Additionally, most blower fans are audible, so if you don’t hear anything when you turn the heater on, the blower fan could be broken.

Other Issues

Depending on the make and model of your vehicle, other things could go wrong with your car’s heater. If you notice any of the above symptoms or if your heater isn’t working, be sure to take the car into Ken Van Damme’s Automotive to have their ASE-Certified technicians diagnose and fix the problem.

How Can Ken Van Damme’s Automotive Help?

With over fifty years of automotive repair experience, Ken Van Damme hires only the most experienced and reputable car mechanics to work for him. If your car heater isn’t working properly, bring it into Ken Van Damme’s Automotive for expert diagnosis and repair. In addition to automotive repair, Ken Van Damme’s offers wheel alignment and is a full-service tire shop. Ken Van Damme’s Automotive is ASE certified, AAA approved, and an official NAPA AutoCare Center. Call or stop by today!

Posted on by Ken-admin
Why Isn’t My Car Heater Working?

Comments are closed.

Explore Other Posts



Pin it