With summer just around the corner, it’s time to get ready for clear skies, glorious sunshine, backyard water hose fun… and heatwaves. You’re probably well-versed on Newton’s most famous law of thermodynamics: When your car is parked under the sun, it basically becomes an oven.
Luckily, your vehicle is most likely equipped with an air conditioning system that can cool your car’s interior in a few minutes. But that might not be the case if your A/C system has been improperly maintained and left to fail over time. A car without A/C during the summer can quickly become unbearable, or even a health risk, so don’t let either happen to you.
Your Car A/C Maintenance Checklist
In this article, we’ll show you how to keep your car’s A/C system healthy and ready to fight the summer heat.

1. Clean or Change Your Cabin Air Filter
Cabin air filters trap dirt and keep debris from entering the cabin through the air conditioning system. Excessively dirty or clogged filters result in poor air flow to the cabin. If your filter isn’t reusable, replacement cabin air filters are relatively inexpensive and easy to install. Most can be accessed through the glove box, but cabin air filters in older cars may require that you dismantle the dashboard. Check your owner’s manual for more information on your specific cabin air filter.
2. Maintain Your Engine Cooling System
Engine temperature can affect the efficiency of your vehicle’s A/C system. Make sure to flush your radiator periodically. Coolant carries heat from the engine block and is cooled in the radiator. An efficient radiator is key to maintaining optimum engine operating temperatures.
3. Check Your Fan Belt
“Fan belt,” “V-belt,” and “serpentine belt” are terms commonly used to refer to the accessory drive belt. Accessories that need power are connected by this belt along with pulleys to the drive shaft. Your A/C compressor, for instance, is a key component that relies on the accessory drive belt, which can crack and break over time. A broken fan belt will leave your compressor with no power and an A/C system that won’t cool.

4. Turn Off Your A/C System Before You Turn Off Your Car
We’ve all been guilty of just turning off the car without turning the A/C off once we get to our destination. But keep in mind that turning your A/C off first can help prolong your car’s battery life. Otherwise, you could shock and damage the A/C system, and your battery will have to work harder to turn the car back on.
5. Park in the Shade
Parking in the shade can help in keeping your cabin cool. Your A/C system will also cool air at a lower temperature, giving it the opportunity to cool the cabin faster.
6. Don’t Max It Out
Keeping your A/C on full blast at all times can place a lot of stress on the different components of your A/C system (including your A/C condenser, A/C compressor, blower motor, A/C evaporator, and A/C receiver drier), and could eventually lead to damage. It could also take power away from the engine, making you compensate with more accelerator inputs, which can lead to lower gas mileage.
Here’s a more efficient way to cool down a hot cabin:
- Before you start driving, open the windows and turn on the fan.
- After you’ve been driving for a little while, turn the air conditioner on and set it at the lowest temperature.
- Once cool air starts to come out of the vents, roll your front windows up and leave the back windows open.
- Keep adjusting the fan until your desired temperature is reached.
- Close your rear windows once the climate is just right.

7. Use It
Your A/C refrigerant carries lubricating oils to critical parts of the system, and keeps seals from drying up and cracking. If you aren’t using your car, make sure you turn the air conditioning on every now and then, and leave it running for 10 minutes. This will also blast out any mildew buildup in the system.
8. Perform Regular Maintenance
A healthy A/C system requires periodic maintenance, so getting it checked at least once a year is vital. Refrigerants that circulate in the system need to be topped up, and a good cleaning will help your air conditioner run efficiently. Your mechanic can also identify problem spots in the system and address them before they become detrimental.
The A/C (also known as HVAC, or the heating, ventilation, and air conditioning system) in your car isn’t just used during the summer. It also controls your car’s interior climate in the winter. Remember that this air will be blowing into your face almost all year-round, so maintaining a clean, fully functioning A/C system is important. Mold and airborne pathogens can circulate in the system and greatly affect your health. Following your car’s maintenance schedule will ensure that your A/C system stays free from health hazards.
Stay cool and safe!
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
6. Don’t Max It Out
“Keeping your A/C on full blast at all times can place a lot of stress on the different components of your A/C system … and could eventually lead to damage.”
“It “could” also take power away from the engine, making you compensate with the accelerator, which “can” lead to lower gas mileage.”
This sentence should say: “It
coulddoes take power away…”. Running the Air Conditioner (compressor) always takes power from the engine. And requiring more power from the engine will always lower gas mileage. That’s how it works.7. Use It
Your A/C refrigerant carries lubricating oils to critical parts of the system, and keeps seals from drying up and cracking. If you aren’t using your car, make sure you turn the air conditioning on every now and then, and leave it running for 10 minutes.
This is good advice. And even if the car is not sitting unused, in the Winter it’s good to run the A/C occasionally, to keep the internal parts and seals lubricated year round.
“This will also “blast out” any mildew buildup in the system.”
This is not the best advice. If there is mildew in the A/C system, which usually grows on the wet evaporator coils, the coils and vent system should be cleaned with a foaming or spray antibacterial system cleaner. “Blasting” the mildew throughout the ventilation system and into the car cabin will make a big unhealthy mess. Any mildew should be cleaned in-place before it gets spread around the car to grow somewhere else.
As stated at the end of the article “Mold and airborne pathogens can circulate in the system and greatly affect your health.“
Here’s a more efficient way to cool down a hot cabin:
1). Before you start driving, open the windows and turn on the fan.
2). After you’ve been driving for a little while, turn the air conditioner on and set it at the lowest temperature.
3). Once cool air starts to come out of the vents, roll your front windows up and leave the back windows open.
4). Keep adjusting the fan until your desired temperature is reached.
5). Close your rear windows once the climate is just right.
Great advice! If the air inside the car is hotter than the outside air, it’s best to get the super-heated air out of the car and replaced it with the relatively cooler air, so the A/C has less over-all heat to remove.