How To Fix It When Your Car Heater Keeps Blowing Cold Air

The need for a working car heater is critical during the winter months. There are plenty of issues with faulty heaters as the weather cools. That’s because many drivers ignore the matter until it’s too late to use the car heater. In any case, nobody wants their car heater to suddenly start blowing cold air instead of heat on a cold winter day. An unreliable car heater can make the cold Canadian winter months nearly unbearable.

Your car’s heating system is designed to keep the interior warm. When this doesn’t happen, something is wrong. A car heater blowing cold air could indicate a heating unit failure.

There might be several causes for a car heater not working, but the two most common are air from the blower not directed toward the heater core or coolant not flowing through the heater core. There are several underlying causes for coolant and air not flowing through their designated paths. An issue with the thermostat or heater core could also be the source of the problem. This article will serve as a guide for how to fix the car heater blowing cold air issue. So keep reading!

How Does a Car Heater Work?

Before you begin tinkering with your heater, you ought to understand how a heater works in a car and what the car heating system components are. A car may be a machine, and every component works in tandem with others. As a result, your car heater doesn’t operate in isolation. A car heating plant includes the following components:

• The core of the heater
• Hoses for heaters
• HVAC instrument panel for the blower motor
• Control valve for the heater

The radiator, thermostat, coolant, and pump are all cooling system components in your car. These systems work together to ensure your car runs as efficiently as possible without overheating or cooling it excessively. Most car heaters use coolant to warm up the vehicle’s interior. This is often how it works:

1. The coolant is heated to a high temperature by the vehicle engine.
2. The coolant is forced into the heater core (which acts sort of like a mini-radiator).
3. Air is forced through the heater core, leading to hot air being blown into the vehicle.
4. When you first turn on the heater, you will notice that the air feels cold for a few minutes because the engine requires some time to warm up and heat the coolant.

Now that you know what the basic components of an automotive heating system are and how a car heater works, let’s learn what causes your car heater to blow cold air and how to fix a car heater that blows cold air while idling or driving.

The Causes of a Car Heater Blowing Cold Air

When a car heater is blowing cold air, the problem is most likely with the cooling system. The foremost common issues are:

Coolant is Running Low.

Despite its icy name, coolant works hard to warm up your vehicle during the colder months. While it keeps your engine cool, it also hovers above the core of your heater and blows all that warm air right into your vents, heating your cabin.

That hot air won’t make it inside your car if you don’t have enough coolant in it. Add some more coolant under the hood to work out if this is the problem.

Problem With The Heater Core

Your heater core must be operational for the aforementioned coolant to reach its destination and warm your vehicle. This component also defrosts your windows and helps keep your vehicle warm. If your vehicle has enough coolant, the heater core might be the source of the cold air blowing through your vents. Other signs of this issue include:

• Inside your car, there’s fog.
• Your coolant is being depleted faster than usual.
• You may also detect a pleasant odor inside your vehicle.

Heater Control Issues

If cold air is blowing through your vents, it might be due to faulty heater controllers in your vehicle. It’s normal for these buttons and dials to become clogged and broken over time and use, making it difficult for them to send a message to heat your car. Fortunately, this is often a simple fix. If you visit your dealership’s maintenance center, they are going to either repair or replace these controls for you.

Thermostat Error

One of the most common issues with car heaters is when the thermostat fails to function properly. If your vehicle’s heating and temperature gauges are misreading and supplying you with incorrect readings, it’s because your thermostat is broken. This prevents it from detecting when the engine is warm enough to permit coolant to enter, leading to cold air blowing out. However, this is often a relatively simple repair that certified technicians at your dealership can complete quickly. Make a meeting, and you will be in a warm car in no time.

How To Fix Car Heater Blowing Cold Air

A heater that blows cold air is one of the most common car problems. This can be caused by various issues, but it is usually simple to resolve. Here are some pointers on how to troubleshoot and repair your car heater:

1. If you have determined that a low coffee coolant level is the source of your problem, simply refill your coolant. If you have recently filled your coolant, you ought to also check for leaks.

2. You need to install a new thermostat to get your heater working again. It is a relatively simple and quick fix.

3. A clogged heater core passage is often flushed, and a clogged heater core exterior is often cleaned manually by removing any clogged debris. In some cases, a replacement heater core may be required. 

4. The blender door will have to be replaced. A jammed blend is typically repaired with other, larger repairs, like water pump replacement.

Bottom Line

This problem appears out of nowhere, and you will face it if you neglect your car and its maintenance. When winter arrives, and you switch on the heat, you are disappointed and begin to wonder, “Why is my car heater not blowing hot air, and how can I fix it if the car heater is not working and blowing cold air?” You can sometimes fix the car’s blowing out cold air instead of heat problems on your own, but other times, hiring knowledgeable people is the best option.

We hope you now understand everything there is to know about car heating system components, how they work to keep you warm inside your vehicle, and how to fix car heater-blowing cold air issues.

Frequently Asked Questions