Car Heater Not Working? Here’s What to do

The winter months bring cold and ice, and car owners need to prepare their car for the harsh weather. This includes checking on your car heater before heading out into the cold. If your car’s heater not working, here are some steps you can take.

How the Car’s Heating System Works

The heater works by heating the air that is blown into the car’s cabin. However, your heater doesn’t blow hot air as soon as you start the car. It’s explained that the colder it is outside, the longer it will take for your car to heat up and keep you warm.

This is primarily because of the thermostat, a temperature-sensitive valve located in the cooling system between the engine and the radiator.

Engines have an ideal operating temperature that’s generally between 90 and 104 degrees Celsius; below that, they don’t run as efficiently and they emit more pollution.

To get there as quickly as possible, the thermostat closes to keep the coolant inside the engine from traveling through the entire cooling system. Once the engine warms up enough, the thermostat opens. That now-warm coolant circulates into the heater core to keep you toasty.

Why Your Car Heater Blowing Cold Air

Several things can potentially go wrong with automotive heaters because, much like a home heating system, many components are 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.

A heater can stop working for several reasons, including:

  • A low antifreeze/water level in the radiator due to a leak in the cooling system.
  • A bad thermostat that isn’t allowing the engine to properly warm up.
  • A blower fan that isn’t working properly.
  • Coolant that contains rust particles or becomes otherwise contaminated and is blocking the heating core from circulating air into the cabin properly.

Depending on the problem, different types of repairs could be required. There really isn’t a heater unit, like a furnace in your house, that you can just replace.

It is more a combination of different things that provide heat into the vehicle. It’s very difficult to give a cost due to the wide variety of possible problems.

Car Heater Isn't Working Properly

7 Reasons Why Your Car Heater May Not Be Working

Before we get into the details of how to fix your car heater, it’s essential to understand what might be causing the issue in the first place. Typically, there are three main reasons why your car’s heater may not be working: a malfunctioning thermostat, a faulty heater core, or low coolant levels.

#1. Malfunctioning Thermostat.

The thermostat is responsible for regulating the temperature of your car’s engine, but it also plays a crucial role in heating up the cabin. If the thermostat gets stuck or fails to open and close correctly, it can affect the flow of hot coolant to the heater core, resulting in cold air blowing out instead of warm.

#2. Faulty Heater Core.

The heater core acts as a small radiator that uses hot coolant to warm up the air before it enters the cabin through the vents. If there’s a leak or blockage in the heater core, it can impact its ability to heat up the air, resulting in cold airflow.

#3. Low Coolant Levels.

Coolant, also known as antifreeze or radiator fluid, plays a vital role in keeping your car’s engine from overheating. It also circulates through the heater core to heat up the air before it enters your car’s cabin. If there is a leak or low coolant levels, there won’t be enough hot liquid circulating to warm up the air.

#4. Faulty Heater Fan.

While you may be getting hot coolant/antifreeze into the heater core, the heater fan, the part that actually blows the heat into the cabin, can break or suffer an electrical short.

#5. Faulty Blower Motor Resistor.

If the blower motor resistor is broken, you might have issues setting the fan speed or getting air at all.

#6. Leaky Radiator.

A leaky radiator could prevent coolant from reaching your heater core and could damage your engine, at worst.

#7. Faulty HVAC Controls.

Simply put, your car’s buttons, knobs, or haptic feedback touchscreens may not be triggering the heating system. Shorts, broken dials, and bad touchscreens can all lead to malfunctions that prevent your heater from working.

Here’s How to Fix a Broken Thermostat

To assuage your fix-it fears and show you just how easy DIY repairs can be, The Drive put together an easy-to-follow guide on how to fix a broken thermostat. You will need to purchase a new coolant and a new thermostat.

We’re not psychic, nor are we snooping through your toolbox or garage, so here’s exactly what you’ll need to get the job done. Also, it would help if you had a drain bucket and a selection of wrenches.

How To Fix a Broken Thermostat

  1. Let the car cool for 15 to 20 minutes.
  2. Locate the thermostat. It will be at the base of the radiator, in between the core and the main hose.
  3. Remove the radiator cap.
  4. For better clearance, lift up the front end of the vehicle.
  5. Place a bucket underneath the radiator and drain the coolant by detaching the hose.
  6. Remove and replace the thermostat.
  7. Reattach the hose to the radiator.
  8. Add the coolant and place the cap back on the reservoir.
  9. Lower your car.
  10. Start the engine.
  11. Wait to see if the heat comes on.
  12. Take a test drive.
  13. Check to make sure the coolant level hasn’t dropped.
  14. If it has, refill it as necessary.

You’re done!

How To Fix Low Antifreeze (Coolant)?

The second-most common culprit is that your car has low antifreeze or coolant. Thankfully, it’s far less time-consuming than replacing your thermostat. All you’ll need is a funnel and a new coolant. Ready?

  • After letting the car cool, remove the radiator cap and place the funnel in the opening.
  • Pour in the new coolant until the reservoir is full. You may need to grab the main coolant hose and physically pump the coolant to ensure there are no air pockets.
  • Replace the radiator cap.
  • Start the car, and check if the heat comes on.

That’s it!

How Much Does It Cost to Repair a Car Heater?

Most heating-related repairs range from $300 to $1,000, but it’s difficult to pinpoint an exact number because of the variety of problems that exist. A decrease in the coolant level or a leak in the coolant system is one of the more common problems.

Similarly, you may ask, how much does it cost to fix a car heater blower?

Know what price you should pay to get your vehicle fixed. The average cost for a blower motor replacement is between $363 and $394. Labor costs are estimated between $87 and $111 while parts are priced between $276 and $283.

How Much Is a New Heater Core? Heater cores generally run between $100-$300. The real cost is due to labor, as heater cores aren’t something most DIYers normally tear into due to their deep locations within the engine bay or underneath the dashboard.

How much is a motor for a heater? On average nationwide, a furnace blower motor replacement costs $400-$600, including parts and labor. A single-speed blower motor costs around $450 to replace while a variable-speed motor costs $600+.

How Much Does a New Thermostat Cost? The average cost of a thermostat is about $45, but if you’re replacing the thermostat, you’ll also need to factor in a new coolant, which will set you back around $8-$15 a gallon.