As the school year draws to a close and the temperatures climb, it’s time to make sure the air conditioning system in your car, truck or SUV is capable of keeping the cabin comfortable.
Before taking your ride in for service, there are a few basic checks you can do at home. With the engine running, open up the vents in the dashboard and turn the fan on. Make sure the fan speed increases as you adjust the control. If the fan isn’t working or a vent has been blocked, cold air won’t be able to get into the cabin.
If the fan doesn’t work, check to make sure a fuse hasn’t been blown. A map of the fuse locations can be found in the vehicle owner’s manual and fuses are easy to change. If the fan works but unpleasant smells are emanating from the vents, a build-up of mold or mildew in the ducts is a common cause. Although some aftermarket sprays claim to be able to eliminate odors from the vents, they may not actually work. In this case it’s best to have your dealer’s service department thoroughly clean the duct-work.
If the fan pushes out odor-free air, turn the temperature control as low as it goes and within a minute or so cold air should emerge. If the air comes out only slightly cooler or not cool at all, several items could be at fault.
While most hybrid vehicles use electrically driven air conditioning compressors, the rest of the vehicle fleet typically relies on a belt to turn the compressor. Like the other accessory drive belts for the alternator and water pump, the compressor belt can wear and stretch over years of use. A vehicle that has been on the road for many years may just need a new belt.
If the belt is relatively slack free and it’s visibly driving the compressor, the system could have a leak and/or need a recharge. The refrigerant in the system can slowly evaporate, or leak out, causing the pressure to drop. Virtually any vehicle built since the early-1990s uses a refrigerant called R134a. Your dealer’s service department can check your system for leaks and recharge it with the refrigerant recommended by the vehicle’s manufacturer.
Vehicles built before the early-1990s actually use an older refrigerant known as R12 or Freon. Freon is no longer made, and older systems need to be upgraded with new seals and other parts to work with R134a. Most older vehicles still on the road have already been upgraded over the last 20 years, but if you have one that’s still using R12, let your service department advise you.
If the air conditioning is at full pressure and still not generating cold air, the problem could be inside the compressor or perhaps in the heat exchanger. Both of these are problems that should be corrected by a professional, preferably at the dealer service department where the technicians have the tools to properly diagnose the problem and ready access to the parts needed to fix it.
The heat exchanger is usually mounted behind the engine compartment bulkhead and it’s not easy to repair at home. Problems with the heat exchanger are also best left to the pros.
If your car isn’t keeping you comfortable when the mercury climbs, it’s best to get the system fixed before you get stuck in traffic on a steamy summer day. Many dealers offer service specials to check and recharge your air conditioning, so watch your newsletter for coupons or contact the service department.