Car AC Blowing Hot Air: Causes and Solutions

If your car AC is blowing hot air, this guide will show you why and what you need to do.


There’s nothing that can be compared to cranking up your car’s air conditioning on a hot day. It’s as good as biting into an ice cream cone or leaping into a chilly pool to feel the rush of icy air against your skin. Your car, on the other hand, may have issues and may not blow the cool air through the vents as you would expect.


Don’t relax and sweat in your seats if this happens. Damntools put together this car AC blowing hot air guide so that you can have a better understanding of the causes and solutions to your car’s air conditioning problems.


How Does Air Conditioner Work in a Car?

Before we look at why your car AC is blowing hot air, let’s take a look at how a car’s air conditioner works so you can figure out why it’s not working.



As its name suggests, the compressor compresses a refrigerant with low pressure and low temperature into a gas with high pressure and high temperature.



The condenser also serves as a small radiator. It accepts high-temperature, high-pressure gas from the compressor and dissipates the heat. The refrigerant condenses, as a result, becoming a high-pressure, low-temperature liquid.


The condenser is also cooled by a pair of cooling fans. While the refrigerant is in the lines, this removes a lot of heat from it.


Receiver/ Dryer

Now that the refrigerant is in a liquid form, the receiver/dryer is responsible for eliminating moisture from it. Desiccants, a moisture-absorbing material, are used to filter the water.


It’s the same substance you’d find in a pill bottle or a new pair of shoes.


To prevent the refrigerant from freezing and clogging the expansion valve, moisture must be eliminated from it. Water freezes at 32 degrees, whereas refrigerant freezes at -200 degrees.


Orifice Tube/Expansion Valve

An expansion valve, similar to the nozzle of a hose, regulates the amount of coolant that travels through the system. It expands as it goes through the expansion valve, lowering both the pressure and the heat.


Not only that, but this method also turns it back into a gas, even though the temperature and pressure are lower.


An orifice tube, rather than an expansion valve, is used in some systems. They both function similarly, with the exception that the former may adjust the size of its aperture based on the evaporator’s temperature. In this kind of system, the receiver/dryer is replaced by an accumulator, which works the same way.



The evaporator functions similarly to a radiator, with refrigerant passing through lines inside. The heat is absorbed and transferred outwards while it is in these lines, lowering the temperature to around 32 degrees.


Coolant is remarkable in that, unlike water, it boils. This not only reduces the temperature even more but also causes it to evaporate, converting it back to a gas.


A fan then pumps cool, air-conditioned air into your cabin over the evaporator. After that, the coolant returns to the compressor as a low-temperature, low-pressure gas, restarting the process.


Why is My CAr AC Blowing Hot Air?

Refrigerant Leak

A refrigerant leak might cause a car AC to blow in hot air. The refrigerant in your car’s A/C system expands and contracts as it eliminates heat and humidity from the cabin. Without sufficient refrigerant levels, none of the other A/C components will work properly.


An outdated hose or a rusty or pierced evaporator can also cause a leak. A refrigerant leak, however, will not be easy to detect. A liquid puddle in or under your automobile is unlikely to be noticed. Antifreeze, unlike motor oil and other important automotive fluids, evaporates when exposed to the air. You might get lucky and find an oily residue near the leak.


One of our professionals must inject dye into the system to identify a refrigerant leak. They will fix and recharge your automobile’s A/C once they have identified the source of the leak, allowing it to blow fresh, cold air once more.


Faulty Electrical System

Your car AC is powered by electricity, and a fault with the electrical system is the most typical cause of hot air blowing from the vent. The entire electrical system will shut down if any one of the fuses, relays, or switches in its arrangement stops working properly.


Due to its intricacy, you should have your electrical system checked by a reputable mechanic.


Condenser Failure

The condenser is an important part of the air conditioning system in your car. The condenser brings the refrigerant down to ambient temperature once it has passed through the compressor.


The compressor’s location, between the radiator and the grille, allows air to flow through the grate, aiding cooling. However, road grit and debris can sometimes get stuck inside the condenser. An obstruction or possibly a rupture, such as puncturing one of the condenser tubes, will occur as a result.


Clean the grille of any sticks, tiny rocks, or other debris. This easy DIY project may be able to solve your AC’s hot air problem. If not, take the vehicle to a collision repair facility. A flush or mechanical repair of the system may be required.


Fans That Aren’t Working

Your car AC system includes a pair of cooling fans. Their job is to help the refrigerant fluid dissipate heat. The refrigerant will not be effectively cooled if either of these components becomes cracked or otherwise damaged—commonly as a result of flying road debris—and your air conditioner will blast warm air.


It is impossible to repair a damaged cooling fan. Replace it at an honest auto body shop.


Cost of Repairing Car AC That is Blowing Hot Air

When you think about how regular maintenance can extend the life of your compressor and keep your air conditioner running at its best season after season, these costs are usually not too much.


Depending on the type and model of your vehicle, a professional AC recharge can cost anywhere between $150 and $300. This service should be added to your vehicle’s maintenance schedule because of refrigerant losses that develop over time. This service is advised every 100,000 miles or so on a car.


You can save money by doing it yourself and recharging your car’s air conditioning, but a proper recharge kit will set you back $40 to $60. This may appear to be significant cost savings and may be more convenient than sending the car to the shop, but it’s critical to understand what happens when you have an AC serviced at a shop versus doing the task yourself before proceeding.


Damntools Will Help Your Car Stay Cool

Come to Damntools for an auto tuneup to keep your car cool. We’ll keep your car’s air conditioning system running smoothly so you can stay cool while driving safely.

Click Here to Leave a Comment Below 0 comments