Car Care Tips

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Maintenance July 23, 2019

Why Is My Car’s A/C Blowing Hot Air?

air conditioner vent

There are few things worse than getting into a hot car on a summer day, cranking up the A/C, and getting a face full of hot air instead of cold. Having a broken air conditioner is definitely uncomfortable, and it can even be dangerous if the car’s temperature gets too high.

We want to make sure you stay cool this summer, so here’s a guide for why your A/C may be blowing hot air.

How Your A/C System Works

Your air conditioner is part of the heating, ventilation and air conditioning (HVAC) system of your vehicle. Within the air conditioning system, there are four main parts: the compressor, condenser, evaporator and blower motor.

air conditioner diagram

To get cool air blowing through your car, your car’s A/C continuously circulates refrigerant (often referred to as Freon) through a closed system. The compressor pressurizes the refrigerant and sends it to the condenser, which then cools the refrigerant.

As the refrigerant goes through the evaporator, it turns from a high-pressure liquid into a gas and becomes cold. The blower motor blows air over the cold evaporator to cool down the air and then circulates the now cold air through the vehicle’s interior.

Read: What Happens When a Car Overheats?

4 Reasons Your A/C Is Blowing Hot Air

When you get in your car on a hot day, your car will likely blow warm air at first. This is normal because the system needs time to cool the air. But if you keep driving and you’re still sweating, it’s time to bring your car to the experts.

We talked to Dale Gilbert, a Technician at Virginia Tire & Auto of One Loudoun, to learn all about vehicle air conditioners. He shared four of the most common problems he sees related to an A/C blowing hot air.

1. Refrigerant Leak 

An air conditioner has a closed system, so it’s designed to not leak. But your vehicle’s A/C endures a lot as you drive. Heat, cold, vibration, shaking, debris—you get the picture. Over time, small parts in the car wear down or get damaged, and you may start to lose refrigerant through small leaks in the system.

Recharging your air conditioner with new refrigerant is the easiest and cheapest fix for an A/C blowing warm air, but it also indicates that you have a leak that needs to be addressed.

If you think your A/C has gradually been blowing warmer air over a period of a couple weeks, you probably have a leak. To find out where the leak is, we can put a special UV-reactive dye into your car’s A/C system. After driving the car for a couple days, bring your car back in and we will inspect the system with a UV light. If there’s a leak, the dye will show it!

After fixing the leak, your car will need to get an Evac and Recharge service. We use a special machine to extract the refrigerant from the system and remove all the moisture. Then, technicians must wait 30 minutes to make sure the system is completely evacuated before adding refrigerant and recharging the A/C system to the correct level.

2. Blocked or Broken Condenser

In most vehicles, the condenser is located at the front of the car near the grille. This is because it uses airflow to cool down the refrigerant as you drive. If you have a bunch of debris blocking the condenser, it won’t be able to cool down the refrigerant properly.

It’s pretty easy to discover if the condenser is blocked, and you can probably remove any debris yourself. After removing the debris, visually inspect the condenser for damage.

Since the condenser is usually at the front of the car, it’s especially susceptible to being hit and punctured by rocks and road debris, causing a leak. If you can see visible punctures and damage to the condenser, you’ll probably need to replace it.

3. Electrical Issues 

An air conditioner depends on several different electrical parts to function properly. If one of them stops working, it will shut down the entire system to protect against electrical fires. So something as small as a blown fuse, bad wiring or minor computer issue could be why your car is turning into a sauna.

Electrical issues are particularly difficult to diagnose, so we recommend letting an expert look at your vehicle to figure out what’s wrong.

4. Broken Compressor

A faulty compressor will definitely cause your car to blow warm air or—even worse—no air. One common compressor issue is a broken or loose serpentine belt, and another is a broken compressor clutch. Compressor issues can be difficult to diagnose and repair, so make sure you bring your car to the experts to make sure the job is done right.

To keep your compressor in tip-top shape, we recommend running the compressor for at least 10 minutes once a month. But don’t worry; most modern vehicles use the compressor to run the defroster too, so you don’t have to freeze running the A/C in the middle of winter.

Cool Off at Virginia Tire & Auto

If your air conditioning system isn’t working properly, don’t sweat it! Our ASE-Certified Technicians can get you back on the road, cool as a cucumber, in no time.

Drop by your local Virginia Tire & Auto and enjoy refreshing beverages in our comfortable waiting room while you wait for your car to be fixed. You can also use our handy shuttle service to get where you need to go, and we offer free loaner cars for repairs over $200. Schedule an appointment online or call 877.597.8265 to talk to our team about A/C services at Virginia Tire & Auto.

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