Summer is coming to a close and you no longer need your car’s air conditioning. This is the time to make sure that your auto’s heating and cooling system is working so that you will be ready for fall. After all, the last thing you want is to start your car only to wonder why the heat in your car’s not working on a cold morning. Here are some suggestions to get your car ready for fall for when you need it most.

How Does The Heat Work In a Car?

car's heater

Make sure your car’s heater is working well

Before you can figure out the best way to get your car ready for fall, it’s helpful to understand how your heating system works. When you switch from air conditioning to heat, a small door called the temperature door redirects air from the blower motor. This moves air over the heater core rather than the air conditioning coils. This changes the temperature of the air.

The other thing which happens is that coolant begins to run through the heater core. The hoses leading in and out of the valve should be about the same temperature if everything is running as it should.

What If Your Car Heater is Blowing Cold Air?

The most obvious sign that your car’s heater is not working right is that it will blow cold air. If you are wondering why does your car blow cold air when the heat is on, there are several possible problems. Once you figure out what is wrong, it is important to get it fixed. Here are a few possibilities if you want to know why your car blows cold air when the heater is on.

You’re Low on Coolant

Your car uses coolant to cool down the engine. This is especially necessary during the hot summer months. When you switch from air conditioning to heating, the coolant moves from your engine to your heater core. As the engine heats up, the coolant heats up and so does the air blowing over the heater core. Air flowing from your vents may be cool at first because the engine has not heated yet. Once the engine has had time to heat up, but the air is still cool, check your coolant levels.

Your Heat Controls are Broken

It’s a fact of life; when you use things for a long time, they can wear out or break. If coolant levels are fine, you may need to replace some of your heat control buttons or even the heat control valve. The heat control valve is under the hood and switches the heat on and off. If it doesn’t work, you may get cool air when you want warm air.

Your Thermostat May Be Broken

car heater blowing cold air

Replenish your coolant if need be

If your thermostat stays on “C” even after your engine is warm, then it’s not signaling for the coolant to go to the heater core to provide heat. Luckily, replacing the thermostat is an inexpensive fix.

You May Have a Water Leak

If you are not getting any heat, check your hoses, radiator and water pump for leaks or damage. If any of these are leaking, your car’s heater will not be able to work properly.

You May Have a Problem with the Heater Core

The heater core is like a small radiator which sits behind the dash board. The heater core has tubing that carries coolant into and away from it. Then there are fans to help disperse the heat. The core handles the vehicle’s defrosting and heating actions. If the tubes get clogged or the fan is not working properly, your car will not heat. Some signs of a problem with the heater core are: foggy windows, a fruity or sweet smell, your car goes through coolant fast, or the engine is over-heating.

There are many possible reasons why your car heater is blowing cold air. If you are wondering how to fix the heat in your car, your best option is to take it to a qualified mechanic. Your heater can break down during the summer when you’re not using it; you may not be aware that there is a problem until you need it. Make sure to check before cold weather is in full swing.

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