Fix A Car Heater

Easy Ways To Fix A Car Heater At Home?

As winters start to come and the winds get cold, you feel like you’re driving through an iceberg. Drivers usually don’t get bothered with the cold as their trusty car heaters always have their backs every year when the chilly winds come. Unfortunately, like all good things that come to an end, your car heater may not always be by your side.

If this has happened and your car heater has stopped working on one cold day, you’d worry that you’ll have to go to the mechanic, stand there while he works on it, and charge an unnecessarily high amount of money. However, you don’t have to worry as its very easy to fix a car heater at home!

It takes a considerable amount of time, though from around 20 minutes to two hours. Heaters aren’t too complicated that you might think. If you have a car heater that isn’t doing what it’s supposed to do, it isn’t a big deal as we’ll let you know what the several causes are as to why it’s not working and ways of easily fixing it at the comfort of your home.

How does a car heater work?

Before you start to figure out the causes and fix the heater, it’s important to know how exactly a car heater works. Your car heater uses the heat of the engine to heat the cabin. To further explain this, suppose your car engine is running, and it gets hot. Water goes to the radiator to cool the engine, so the engine cools down. When the heater is turned on, hot water is circulated through a heat exchanger in the passenger compartment. Although radiators are important in cooling an engine, you should always keep your radiator in the best condition by using a good quality radiator flush.

Air is passed from the blower of the cabin through the heat exchanger, and the air gets hot. There is a thermostat valve in the engine. It makes the heating system work. The thermostat valve is very important. It:

  • It keeps the engine operating at optimum temperature. Some people have witnessed that their engine sputters when the heater is on. This is, however, due to many other reasons.
  • It is the reason that the hot water goes to the cabin first.

Reasons why your car heater isn’t working

There are several reasons why your car heater doesn’t help save you from that cold breeze.

Faults in the thermostat

A faulty thermostat is usually the most common cause of a car heater not being able to work properly. This part can mess with the heat and the cooling system of your engine.

Low antifreeze

Another common issue is a low amount of antifreeze. The hot fluid cannot enter the heater core when the coolant or antifreeze levels decrease. As a result, your cabin gets cold. This can happen if the engine is working hard or overheating, or isn’t filled with enough coolant/antifreeze. Remember that the engine should have enough antifreeze. There can be a few reasons why it had less antifreeze, so be cautious if the antifreeze is leaking or if there’s any other reason why is it so less.

Fault in the heater fan

The antifreeze/coolant could be entering the heater core, but there could be a chance that the problem is with the heater fan. The heater fan is the part that blows the air into the cabin. If it’s broken, the hot air will stop coming out. So, you have to find a way to stop antifreeze leak.

Radiator leak

If your radiator is leaking, then it might cause why coolant isn’t getting to your heater core. A leaky radiator can also cause damage to your engine. However, you can replace the radiator with a new one to fix the issue.

Easy ways to fix your car heater

A broken thermostat or a low amount of antifreeze can easily be fixed at home, and your car heater can start working again.

Fixing a broken thermostat

Working on your car is a dangerous task, and to avoid any inconveniences and injuries, its best to be as cautious as possible and do everything carefully. To be safe as possible, wear mechanics gloves and safety glasses. You’ll have to keep a drain bucket, several wrenches, a new thermostat and coolant to replace the old broken ones. Steps to fix the thermostat are as follows

  • Let the car cool for about 20 minutes.
  • Find where the thermostat is. It’s under the radiator between the main hose and core.
  • Remove the cap of the radiator.
  • Lift the car from the front.
  • Put a bucket beneath the radiator and detach the hose to drain the coolant.
  • Remove the old thermostat and replace it with the new one.
  • Reattach the hose.
  • Add coolant and put the cap back on.
  • Lower the car.
  • Start your car’s engine.
  • Wait if the heat comes on.
  • Go on a test drive.
  • Check if the coolant hasn’t decreased in amount.
  • If it does, you can refill it.

Fixing low antifreeze

Low amount of antifreeze or coolant is the second most common cause of why your car heater isn’t working. This method is also less complicated and is quicker than replacing your thermostat. You’ll need a funnel and coolant for fixing it.

  • After your car cools for a bit, remove the cap of the radiator and place a funnel in the opening.
  • Fill the reservoir with coolant until it’s full. Then, grab the main hose of coolant and pump the coolant physically to make sure no air pockets are left.
  • Put the radiator cap back on.
  • Start your car and check to see if the heat is on.


If the weather gets cold enough, driving can be very uncomfortable even if you’re wearing plenty of clothes. Times like these is when you realize that your car heater is super important, so always check if your car heater is working fine to avoid getting frozen.