How to Fix a Car with No Heat

Tips and Tricks on How to Fix a Car with No Heat

If you live in an area with snow or in a place where the temperature is always low, you are probably no longer a stranger to being uncomfortable when you are driving. You will end up shivering if your heater is not working. This is a miserable situation that you would not want to experience, but the reality is that it can happen to anyone.

In the rest of this post, I will let you know how to fix a car with no heat. The first step is the diagnosis of the problem. Once you are able to pinpoint the exact reason for the issue, this is the only time that you can proceed. Fortunately, even without the help of a mechanic, this is one problem that will be easy for you to fix.

What You Will Need to Follow this Tutorial

The required materials will be different depending on the source of the problem. Generally speaking, however, these are the materials that you will need:

  • Coolant/antifreeze
  • Water
  • Thermostat
  • Non-contact infrared thermometer
  • Blend door actuator

Step-by-Step Guide on How to Fix a Car with No Heat

As shown in the short video below, some of the most common reasons why there is no heat in the car would be not having enough antifreeze and coolant, problem with the thermostat, defective blower motor resistor, broken heater core, damaged heater control valve, and a bad actuator blend door, among other things.

Check Coolant and Antifreeze

This is the simplest way to deal with your car if it is not blowing hot air. If there is no coolant or antifreeze, the heater will not function at all. You might also want to inspect for leaks. The coolant that is circulating from the engine is basically the one that is responsible for the production of heat.

Turn off the engine and allow it to cool for a while. Open the hood and look for the header tank. You can check the manual of your car to see exactly where the coolant is. If it is empty, you have to fill it with water or coolant. If it is full, this means that the coolant/antifreeze is not the problem, after which, you can proceed to the next step.

Make Sure the Thermostat is Working

If the thermostat is broken, this is one more thing that could limit the functions of the heater. To be specific, you might have a stuck thermostat. In other instances, it can just be too old and it might already be asking for a replacement. The thermostat opens and closes the circuits in the cooling system of the engine as it produces heat. If it is in a position that is locked, hot air will not pass through.

To replace the thermostat, all that you need to do is remove the lower radiator hose and install a new thermostat.

Inspect the Heater Core and Heater Core Valve

If the thermostat seems to be working fine or if you have already replaced it but the heat produced is still not enough, you have to check the heater core and the heater core valve. The heater core is a small radiator that heats the car. This is done through an integrated fan that blows hot air.

You will need to check the temperature of the heater core and make sure that there is enough hot air passing through the hoses. A non-contact infrared thermometer will prove to be a handy tool to complete the diagnosis. Flushing the heater core is the best thing that you can do to remedy the situation if the thermometer shows that it does not get hot at all.

Bad Condition of the Blend Door

If at this point, your heater is still not working, the next component that you need to check is the blend door. If you change the thermostat from hot to cold, there must be a noticeable sound, which will give you an indication that the blend door is working perfectly fine. If the blend door does not open, heat will not be able to pass through.

There are times when the blend door actuator may need to be changed. In other cases, meanwhile, the problem could be with the linkage or the wires.

Pro Tips

To make sure that you will have enough heat when driving, here are other tips to keep in mind:

Fix a Car with No Heat


  • As an alternative to the things that have been mentioned above, you might want to buy heated seats for your car. They are available in a variety of designs and most of them can be controlled individually based on the temperature that you prefer. This can be a more expensive option, but this can indeed prove to be a quick fix.
  • A space heater or a portable heater will also be a good temporary solution. Nonetheless, keep in mind that it will not be able to deliver long-term comfort as the amount of heat that it can produce is limited. This only works if you are still waiting for the main problem to be fixed.
  • Make sure that the radiator is not completely covered. There should be enough airflow. You can cover it with cardboard, which will stop the airflow and will heat the coolant quicker. In turn, this will also make it quick to produce the hot air that can be enjoyed in the car.
  • The worst problem can be associated with a leaking head gasket. Unfortunately, this is no longer a simple DIY task. You will need to consult with a trained mechanic. This can also be a costly repair.
  • Inspect the doors and the windows. See to it that they are working perfectly and there are no gaps or anything else that could let cold air in and hot air escape. You can also consider insulation so that you will be able to trap warm air.


At this point, I hope that you already know how to fix a car with no heater. It is quite a simple task, but it can be quite tedious since there are multiple components that you have to check. The coolant can be the most basic problem, but in worse instances, there are parts that are not working properly, and hence, they might require extensive repair or replacement if they can no longer be spared.

Have you tried fixing your car’s heater before? Are there other tips that you would like to share? Do not hesitate to leave a comment below.