Car’s Air Conditioning ONLY Blowing Hot Air? Here’s Why!
May 03, 2021
It's one of THOSE summer days in Ottawa. The weather's so blazing hot you can barely drag yourself from your air-conditioned house out to the car. Oh well, at least your car will be nice and cool inside once the AC's cranked up.
Except it's not. Cool, that is. When you turn on your vehicle's air conditioning, all you feel is a blast of hot air from the vents. "Why? Why? Why is my car AC only blowing hot air?" you groan.
Here are 6 possible reasons your air conditioner is blasting hot air, together with solutions for each one to help keep your car cool.
1. Malfunctioning Electrical System
Your vehicle's AC is electrically powered, and the most common reason for car air conditioning that blows hot air is an electrical system malfunction. If any one of the components in its arrangement of fuses, relays, and switches stops working as it should, the entire electrical system will shut down.
SOLUTION: Due to the electrical system's complexity, you should have it checked out by a reliable mechanic.
2. Low Or Leaking Refrigerant
Refrigerant (also known as "coolant") is a fluid that cools your passenger cabin as it alternately expands and condenses, circulating throughout the air conditioning system. Since the system is sealed and airtight, your refrigerant supply cannot evaporate or get used up. A low level of refrigerant means you've got a leak somewhere, which should be repaired before your coolant is topped up.
Locating and fixing a refrigerant leak is a complicated task, best left to an auto repair professional. If you're driving a pre-1995 vehicle, Ontario law makes it even more complicated; you must have it leak-tested by a technician with an Ozone Depletion Prevention certificate to ensure that you won't be "discharging an ozone-depleting substance."
SOLUTION: Sorry, there is no option for DIY here. As an Ottawa car owner, you'll need a certified technician to handle this one.
3. Corrupt Condenser
The condenser is a vital component of your automobile air conditioning. Once the refrigerant has moved through the compressor, the job of the condenser is to bring it down to ambient temperature.
The compressor's position -- at the front of your car between the radiator and the grille -- allows air flowing through the grate to help with the cooling process. However, sometimes it also allows road dirt and debris to get trapped inside the condenser. The result will be a blockage or even breakage, such as the puncturing of one of the condenser tubes.
SOLUTION: Remove any sticks, small rocks, etc., from the grille. This simple DIY action might stop the problem of your AC blowing hot air.
If not, take the car to a body shop. The system may need flushing or mechanical repair.
4. Run Down Compressor
Your car's AC compressor is responsible for pressurizing the refrigerant fluid and circulating it throughout the system of hoses and tubes to cool your car's passenger cabin. As a hardworking component, the compressor is very vulnerable to failure due to wear and tear. In some car models, it can also fail when you start it after a long period of inactivity -- such as when you try to switch the air conditioning on for the first time in summer. A failing compressor may cause your engine to overheat.
SOLUTION: Keep your compressor in good shape by turning on the air conditioner, set to HIGH, once every month, even during our cold Ottawa winters. If the compressor has already failed, though, contact a body shop for repair.
5. Broken Cooling Fans
A pair of cooling fans form an important part of your car's AC system. Their purpose is to help remove heat from the refrigerant fluid. If either of the becomes cracked or otherwise damaged -- usually due to flying road debris -- the refrigerant will not be adequately cooled, and your air conditioner will blow warm air.
SOLUTION: A broken cooling fan cannot be fixed. Get it replaced at a reliable auto body shop.
6. Dirty Air Filter
Some automobile makes, and models are equipped with a cabin air filter. Just as with your HVAC filter at home, your car's air filter gradually gets clogged with dust and debris, so regular changing is essential. Besides hot air blowing from your vents, other signs that your cabin air filter could be blocked include musty smells or overly loud noises when you're running the AC.
SOLUTION: You can buy a new filter and change it yourself; your owner's manual will tell you how often it needs to be replaced. Or if you prefer, have the cabin filter changed for you as part of a professional auto tuneup.
Bemac Will Help Your Car Stay Cool
Come to Bemac for an auto tuneup or mechanical repair in the Ottawa-Gatineau area. We'll take good care of your air conditioning so you stay cool and drive safe.
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