How to Fix Car Heater Blowing Cold Air

Once a vehicle’s car heater starts blowing cold air instead of hot air then there’s a problem with the car heating system.

A car heater’s main purpose is to introduce warmth (hot air) into the car when there’s excess cold introduced by the air conditioner. Also, the air conditioner helps make the cabin chill out and prevents excess heat.

If one of these systems works interchangeably or fails at any point while driving then the driver (and passenger) would experience extreme discomfort.

Your vehicle can also blow cold air while idling, when stopped, or intermittently

The problem is likely caused by a faulty cooling system, low engine coolant level, a faulty thermostat, and others that’ll be discussed below.

Additionally, a car heater blowing cold air can be fixed by refiling the coolant, getting a thermostat replacement, or getting a new heater control, amongst others

In this article, I’ll show you possible reasons why your car heater is blowing cold air and how to fix it.

Why is My Car Heater Blowing Cold Air

A car heater blowing cold air Is a minor issue since it is easy to diagnose and repair.

For those who don’t know, here are possible reasons why your car heater is blowing cold air instead.

1. Low Engine Coolant Level

Asides from keeping the engine running at a stable temperature, coolants are also crucial for the proper functioning of the car heating system. Once the coolant goes below the required level, the heater will start blowing cold air because it’s committed to making the engine function at that point until the next coolant refill is done.

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2. A Problematic Thermostat

A thermostat helps the car engine in reaching and maintain a standard working temperature as soon as possible. Without the engine attaining that recommended temperature, then your car heater will be blowing cold in the meantime.

3. Air in the Heating System

If air gets into the heating system due to component(s) damage then your car heater might blow cold due to the leakage.

4. Damaged heater control

Since these components are controlled by buttons and controls, it may be possible that the heater control is faulty and needs repair or replacement. Also, it could be that the button is frozen and as such, makes you think that the car heater isn’t functional.

5. Spoilt Heater Flaps

The heater flaps are used to regulate the inflow of hot and cold air into the vehicle. any damage to these heater flaps will turn the check engine light on until a replacement is done.

6. Bad Heater Core

The heater core controls the car’s heating system and as such any defects that occur to it will affect the overall functioning of the heating system.

Car Heater Blowing Cold Air – FIX

We’ve seen the possible reasons why a vehicle heater will blow cold air, let’s see how to Fix the cooling system issue.

1. Refill the Coolant

When the heater blows cold air, the first thing you must check is the coolant level.

  1. Once you’ve purchased a quality coolant from Amazon, park your car and leave it to cool off
  2. Raise the hood of your car and open the radiator cap to check its level, same with the reservoir tank
  3. You can now fill the coolant in the radiator to the brim while making sure the reservoir tank is filled to the manufacturer’s recommendation using the MIN and MAX lines.
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Also, ensure not to overfill or overfill any of these vessels to avoid engine troubles.

2. Heater Control Replacement

If you notice that the fault is from your heater control then you can seek the service of an auto engineer to get it fixed.

You can also purchase a heater control from amazon and then proceed to follow YouTube guides in fixing it yourself.

3. Replace problematic Thermostat

If you notice the fault is from your thermostat after testing and diagnosing it then you can initiate a replacement.

4. Remove the blockage in the Heater core

You can perform a visual inspection of the heater core to identify if the problem is from dirt accumulation on the pipes. You can proceed to clean off the blockage by cleaning the outside of the heater, flushing the heater pipes, or manually removing dirt particles.

If the issue still persists after the above troubleshooting then you should resort to buying a new heater core.

5. Heater Flaps Replacement

Also, inspect the heater flaps or blend doors and perform a replacement if possible

6. Bleed the cooling system

Bleeding the whole cooling system will get rid of trapped dirt, airlocks, or other foreign material. The bleeding process could be quite tedious for newbies but it’s worth it, nonetheless, you can seek the attention of a car heating service and repair

7. Use the Windows

If you can’t implement any of the above fixes then you should consider winding up the windows while driving to prevent air from coming in thereby releasing heat into the car.

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Do this while the Air conditioner is turned off though.

Car Heater Blowing Cold Air Cost To Fix

It’s quite hard to determine for sure what could be the reason why a car heater is malfunctioning due to the various causes but we’ll put the repair cost at an estimate of $10 to $1,000. It might cost more depending on the model.


Can I Heat My Car Without a Heater?

Yes, there are other economical ways that can heat up your car but you can’t compare their efficiency to that of a car heater. Instead of car heaters, you can adopt blankets, winding up of windows especially when idle, or heated seats.


A car heater blowing cold air Is a minor issue but at the same time, it could cause discomfort to car owners especially those who frequently make use of the heating system.

In this article, I’ve outlined all the possible reasons why a car heater will blow cold and ways to fix them.

However, if you’re inexperienced and can’t fix your car yourself using the above guide then it’s advisable to call the attention of a mechanic.