Car heater blows cold air – possible reasons and what you should do

Our cars are not only a means of transport, but also provide a reasonable level of comfort during the journey. It’s hard to deny that vehicles have become an indispensable part of our daily lives.

When winter comes and the temperatures drop, you’ll love driving in the comfort of your car’s cabin. You turn on the heater but wonder ? Why is my heater blowing cold air into my car??

Car heater blows cold air - possible reasons and what you should do

Instead of just scratching your head for hours to spend hundreds of dollars on a mechanic later, you may want to try some fixes we offer.

We also present the possible causes of this malfunction so that you can take precautions later on.

Possible reasons why your heater blows cold air

Low coolant level

Coolant is 50% antifreeze and 50% water. This fluid is primarily responsible for supporting the heating system. When you turn up your heater, this coolant facilitates the flow of heat in your cabin. However, you should keep in mind that it is okay if your heater only blows cold air for the first minute and then blows hot air, since your engine usually needs some time to heat up in winter.

However, if this continues for a longer period of time, this is definitely an indication of a low coolant level, which could be due to a fuel leak or radiator/hose problems.

Fix fill the coolant level up to the required mark according to the manual of your vehicle. A coolant change is usually covered as part of the routine maintenance cycle and can cost around $150-160. However, if the problem is due to a leak, get ready to shell out $600-800. However, we recommend that you try to find the leak yourself and see if you can fix it yourself.

Thermostat interference

The thermostat acts as a valve to regulate the amount of coolant flowing to the radiator. Once you start your engine, the thermostat will turn on when it reaches a threshold temperature. then the thermostat will allow the coolant to flow downwards.

Your thermostat may be stuck either open or closed. If it is closed, the coolant motor will overheat faster and self-destruct over time. Since no coolant can flow into the heater core, naturally only cold air comes in.

on the contrary, if the thermostat is stuck open, the coolant flow is continuous, resulting in a cold heater core.

  • Park your vehicle and make sure it is stationary
  • Make sure the engine is completely cooled down when you start it
  • unscrew the thermostat housing present at the end of the upper housing for the radiator.
  • Replace the defective thermostat with a new one and then screw it tightly to the system.

Defective radiator

Car heater blows cold air - possible reasons and what you should do

technician holding dirty air filter for car

A heater core with dust and lint can also be the reason your heater is blowing cold air. Since the passage through the core is quite narrow, there is a high probability that dirt and grime will build up on the surface over time.

Also, the fins inside the core can easily become clogged.

Fix: manual cleaning of the core can solve the problem in most cases. For the inside of the heater core, flushing the core can be very helpful. This can cost you on average between a hundred and a few hundred dollars.

Jammed mixer door

A blocked blend door can prevent hot air from entering the cabin. Apart from this, your heater buttons may also jam, resulting in poor air circulation. Prolonged use often leads to such problems.

Remedy: replace the gear depending on the model of your car.

Air bubbles in the cooling system

The elevated position of the radiator in the system can often cause air bubbles to enter the coolant. Heat is then not transferred properly, resulting in a cold heater core.

  • Disengage the heater system to the maximum.
  • Remove the cap from the coolant tank and fill the coolant to the brim.
  • Fire the engine once and leave the tank cap still open.
  • After a few minutes, you will notice that the thermostat is on.
  • close the lid now and test your heating system.

Functioning of a car heater

Auto heating systems are divided into three types: water-cooled engines, air-cooled engines, and electric. However, since the problem we are focusing on is more pronounced in water-cooled engines, let’s find out how these engines work.

Water-cooled engines operate on the basic principles of heat. As the temperature of your engine rises, it generates heat, which then helps transfer hot air into the cabin. However, constant exposure to heat can cause your engine to overheat.

To combat this problem, these engines have a component called a coolant which absorbs the heat to avoid overheating. Once the coolant is heated to a few hundred degrees, the heat flows through the radiator into the thermostat, which lowers the temperature.

To remove the hot air, a small heater core is also placed along with a built-in fan to blow out the air.

In summary, the heat generated by your engine flows through a coolant that then heats the radiator and then transfers heat inside the cabin through a fan.

What if the air is warm but not hot enough??

Low heat may be due to loose plugins somewhere in your system. In addition, their thermostat could also be stuck, causing the hot coolant in their heater core to be low. This leads to a warm air tone instead of a hot bump.

if your thermostat is stuck in a partially open position, the heater core may not be receiving an adequate supply of coolant. In addition, as your car heater ages, it can also pick up small particles of dirt and debris, causing a blockage that impairs / slows down its function.

But don’t worry, regular maintenance and a regular coolant change can easily fix this problem.

Regular maintenance helps a lot

most of the problems related to your engine and cooling system can be solved if you change your fluid regularly. This also improves the quality of their transmission. Since a transmission swap can cost between $2000 something? $6000 it only makes sense to spend a portion of that amount at regular intervals instead.

  • OEM oil change, quarterly
  • Tire rotations, twice a year
  • Checking the engine’s faulty transmission, quarterly

Now that you know the real reason for the cold air from your car heater, you can keep yourself from wilting in a harsh winter. Most of these problems can be fixed without help, while some require the expertise of a professional.

But if you are a person for whom comfort is a priority, these upgrades and fixes will be worth your penny.

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