Most of us take our car heaters for granted, not knowing how they work other than you run the engine, crank up the temperature, and hot air blows out from the vents. But what happens when the heat stops coming? There are few things as miserable as driving in freezing weather with no heat in your car and fingers frozen to the steering wheel—but with winter on the way, getting the problem fixed ahead of time is critical.
Here are five potential causes for no heat in your car (Truck, SUV, Crossover, Minivan, etc.)!
1. Problems with Your Blower Motor or Blower Motor Resistor
Your blower motor is the component that pushes air through your car’s heating or cooling system. Without it, there’s no circulation of air—hot, cold, or otherwise. The blower motor resistor is the part that controls the fan speed of the blower motor. Both of these components can fail, resulting in the heating system simply not working. This is sometimes preceded by a slight hum or vibration, but many times there’s no warning at all. Depending on the kind of car you drive, you’re looking at a range of $300 to repair the problem.
Example: The repair cost for a Blower Motor and Blower Motor Resistor for a 2010 Nissan Altima is between $260 – $320, parts and labor (taxes not included).
- $180 – $220 parts
- $80 – $100 labor
- $260 – $320 in total repairs
2. Clogged or Inoperable Engine Thermostat
The function of an engine thermostat is similar to the one in your home: it reaches a certain temperature and keeps it there. A car’s engine thermostat sits between the engine and the radiator and works by restricting the flow of engine coolant from the engine until the engine reaches a certain temperature, typically between 195-205 degrees. If the thermostat clogs or does not function correctly, your engine won’t rise to full operating temperature, thereby leaving cold or barely warm air blowing from your vents. This not only makes for a miserable commute but can also result in poor gas mileage.
3. Engine Coolant
Dirty or low engine coolant can make it so your car heater works only periodically. If you’re experiencing on-again, off-again performance from your heater, this could be a sign you need to have your engine coolant inspected.
4. A Faulty Heater Valve
This is the component that tells your car’s heater core to blow at a certain temperature when you select cool, warm, or hot on your control panel. When the heat bypass valve isn’t working properly, it can restrict the flow of coolant to the heater core, which can cause inconsistencies in the temperature of the air coming through your vents.
5. Heater Core issue
You probably didn’t know you have a mini radiator living inside your car’s dashboard called a heater core. This is what your blower motor pushes air over to send warm air coming through your vents. When the heater core goes, it’s an expensive replacement that can sometimes take all day to perform. One of the dead giveaways is a maple syrup-type smell inside your car. Sometimes you even get a pool of liquid on your passenger-side floorboard. If you spot this, use caution! The liquid can be scalding hot. There are, however, a few things a mechanic can try before replacing the heater core, such as changing the coolant or flushing the system. Another approach might include reversing the flush of the heater core itself to purge it of sediment-heavy coolant.
Example: The repair cost to replace a heater core for a 2010 Nissan Altima will set you back about $1,000. This includes parts, labor, recharging the AC and replacing all the engine coolant (taxes not included).
- $185 – $215 parts
- $700 – $900 labor
- $885 – $1,115 in total repairs
If your heater is working fine, don’t get complacent. Keep it operating by having your coolant changed at the recommended intervals. If you just tried your heater and it’s refusing to work right, there’s no time like the present to take care of it. Use Openbay to find qualified mechanics near you who can fix the problem before the weather turns really nasty.
Written by one of Openbay’s ASE Certified Technician and frequent contributor to this blog, specializing in all things automotive service and repair.