Car Air Conditioning: Tips to Keep it in Shape and Cold

By Joni Finkle 04/01/2022 8:00am

Car owner checking air conditioning temperature

As warmer summer weather approaches, your car’s interior needs lots of air conditioning to get you and your tribe around town comfortably. We often take our car’s air conditioning for granted. But in truth, cool air is not just another feature. It’s a necessity.

So what can we do to encourage the health of our cars’ air conditioning before anything goes wrong? Although car manufacturers are continually improving in-car climate control, there are a few things we can do.

To find out, we’ve asked Kelley Blue Book’s in-house service and maintenance expert Gary Hardesty, an A.S.E. certified master technician. His advice can help us keep cool all year long, especially in summer.

This article will cover common car air conditioning issues, plus key tips, and information about your air conditioning upkeep.

1. Watch High Engine Temperatures on Steep Grades

car traveling up a steep grade with air conditioning on

If you’re traveling uphill on a steep grade and your car is loaded with people and gear, keep an eye on the engine temperature. The stress on your engine could cause the A/C coolant to become overheated. If this happens, Hardesty says to turn your heat on full blast for a few minutes to lessen the burden on the car’s cooling system.

2. Keep ‘Inducts’ Under the Windshield Dry and Clear

Our expert says that a common cause of mold entering the air conditioning system comes from water, dirt, snow, or moisture entering at the base of the windshield. It turns out this is the optimum location for your car’s air conditioning intake. Sadly, it’s also the worst place to have moisture and debris gather and enter the air conditioning, creating mildew. Hardesty suggests cleaning regularly using a vacuum to clear any water, dirt, or leaves that accumulate there.

3. When Odors are Detected, Act Quickly

Woman smelling odor in air conditioning vent

Strange smells and their origins can be dangerous signs. Other odors may just be from the previous owner of your car who was a smoker or who allowed pet odors to accumulate. In these cases, Hardesty says that some orange peels placed on the floor of your car for a few days will help. Other options are to spray an odor neutralizer like Ozium into the vents or change the air conditioning filter (skip ahead to tip No. 6 for more details).

But there are some odors to watch out for that might suggest a more significant issue:

  • Must or Mildew OdorA musty smell could mean mold entered and remained undrained in the evaporator inside your cooling system. One such way to deal with this: You can run your heater on high for a little while to dry out the evaporator/heating core.
  • Sweet SmellA sweet smell can mean an antifreeze leak. A professional mechanic can run a leak test to confirm the issue and present service options.
  • Gas OdorWhen you smell gas coming from your A/C unit, it could indicate a gas leak, which is hazardous. However, it could also mean your gas cap is not secure or is faulty. Either way, do get the issue resolved quickly.

4. Always Read Your Owner’s Manual Section on Your Car’s Air Conditioning

Did you know that mechanics refer to your owner’s manual before working on your car? Since your manual probably sits right there in your glove compartment, be sure to read the part about your car’s air conditioning so you can learn a few things. For instance, should you use green or red antifreeze in your vehicle? Who do you inquire with if there are recalls on your year/make/model vehicle? Get all the facts before you see a mechanic.

5. Add Air Conditioning Checkpoints to Your Regular Car Maintenance Schedule

Mechanic With Checklist Including Car Air Conditioning

Always read your owner’s manual for the manufacturer’s suggestions, but many professionals recommend you get your vehicle’s A/C checked annually. Your system is exposed to heat from the engine, fast stops, road debris, and fender benders, so things can often go wrong. The benefits of keeping on top of A/C maintenance can include improved gas mileage, a more environmentally friendly vehicle, and improved air conditioning comfort in your car.

6. Change the A/C Filter When Needed

Did you know that your car boasts an air conditioning filter, typically behind your glove compartment, is something that you can potentially change yourself? If your car odometer reads between 15,000 to 30,000 miles, it may be time to replace your filter. Benefits of changing your filter include a stronger airflow, less unpleasant odors, and less dust settling on your interior surfaces.

7. Open Windows and Start Driving, Then Turn on Your Air 

Experts, including Hardesty, recommend opening your car’s windows a few moments before running your air conditioning. As they recommend, begin driving before turning on the A/C to increase the longevity of A/C in your car. Basically, avoid sitting idle for an extended period with air conditioning blowing to give the A/C system less heavy work.

8. Use the Fresh Air Vent, but Only Occasionally

Recirculation and fresh air buttons interior of car

It can be perplexing to choose between these two modes. One is for recirculation, and one brings fresh air into the car. Experience teaches us that fresh air isn’t fresh when riding behind a diesel truck or in a smoggy city area. But remember that the air inside can also become stale when you only use the recirculation button. Use the fresh air vent for exactly that — to bring fresh air into the cabin.

9. Intermittently Run Your Air in Defrost Mode

According to our expert, the defrost mode in your car does more than take the frost off your windows. It prevents mildew and clears up moisture inside the A/C unit. Doing this around once a week for 5 to 10 minutes can help you avoid mold, mildew, or other unpleasant odors in your car.

10. Keep the A/C on the Coldest Setting When in Use and Adjust the Fan to Comfort

Most experts agree that choosing the lowest temperature of your air conditioner is more efficient for the car’s cooling system and saves fuel. Why? Hardesty says that most cooling systems only cool the cabin by 30 degrees and then stop. If you reach that point, then set the temp higher, you also activate the heater. This dual effort causes stress on the system and uses more fuel. Instead, set the A/C fan to low and rotate the vents away from you.

Common A/C Issues 

So remember, like many other systems in your car, air conditioning weakens with wear and tear. Common and costly issues include:

  • Refrigerant leaks
  • Defective cooling fans
  • Condenser and compressor malfunctions
  • Mildew in the vents

For your car’s heating and air conditioning, service and repair can range from $300 to $2,000, depending on what needs work, so it’s something to watch and maintain. You can also go to our car maintenance tool to get an estimate for A/C repair before you make an appointment with your repair shop.

So, no matter where you live, these tips can help you get the most comfort out of your air conditioning system in the summer without undue wear and tear.

Remember to always refer to your owner’s manual to get more specific information about your vehicle’s systems and apply the best strategies to keep them running smoothly. Also, keep an eye out for tale-tell signs that your vehicle’s air conditioning needs professional care.