5 Issues Affecting a Car's Heating System

A silver car.

As the blustery months of winter arrive, folks will depend on their car's heating system to keep them toasty during their daily commutes. The heating system is also designed to melt ice buildup and clear fog on the windshields to give the driver a clear view of what lies ahead. Unfortunately, a car's heating system can occasionally fail, not only leaving you in the cold, but also impairing your vision, which can lead to safety issues.

How a Car Heater Works

A car engine requires coolant to absorb the heat it creates during operation. The coolant circulates through the engine and then the radiator where it is cooled before completing the whole process again. Before reaching the radiator, the coolant passes through a heater core, which is similar to a radiator as it absorbs heat from the coolant.

A blower fan, most often located under the dash, blows air through the heater core where it is circulated through the cabin of the vehicle. The heated air is also directed through a circuit of ducts to the windshields for deicing and fog removal when necessary.

Several problems can occur that could cause your car's heater to malfunction. They are outlined below.

1. A Faulty Thermostat

A tan car.

The thermostat is a device designed to control the coolant circulation through the engine. One of its primary functions is to stop coolant circulation during the first minutes of engine operation. This allows the coolant to heat up quicker, which in turn warms the engine and its components, or "heater core" faster. Once the thermostat reaches a preset temperature, it opens and allows normal coolant circulation through the engine. A faulty thermostat, or one that fails to hold back the coolant until it is warmed, will increase the time it takes to provide heated air to the cabin.

2. A Faulty Heater Core

The most common problem associated with a failing heater core is it develops a leak. Not only will a leaking heater core fail to provide adequate heat, but also could allow coolant to leak into the car's cabin. If you notice coolant pooling in the floorboard of your vehicle, it is most likely time to replace the heater core.

3. A Faulty Heater Hose

A heater hose carries the heated coolant to and from the heater core. If it bursts or develops a leak, the heated coolant will not reach the core, which in turn will prevent the core from heating and providing warm air to the car's cabin.

4. A Faulty Fan Motor

A black car.

The fan motor is designed to blow air over the heater core where it is heated and to circulate the conditioned air throughout the vehicle's ductwork. If the fan motor fails to activate, it is most often one of two problems. Either you have a burnt fuse in the fan blower circuitry, or the fan motor itself is faulty.

5. Low Coolant Levels

Inadequate coolant levels could result in your car's heater not functioning properly. Low coolant levels certainly can cause other issues, some major, with the operation of your vehicle. However, when there is a shortage of coolant within the system, there is not enough coolant to heat the heater core.
Heating issues with a vehicle are not always easy to correct. A blown fan motor or heater core, for instance, could result in significant repair bills. Maintaining coolant levels and periodic flushing of the coolant system can extend the life of your car's heating components.