ATLANTA, Georgia -- To keep cool during the hottest days of summer, NAPA AUTO PARTS encourages motorists to have their vehicle air conditioning checked by a qualified auto technician. An air-conditioning system that operates marginally is more likely to fail during hot weather. Having the air conditioning system inspected and serviced now will help assure the system is working properly when motorists need it most.

Vehicle air conditioners are like small refrigerators that cool and dehumidify the air that flows into the passenger compartment. Because the system uses a refrigerant to cool the air and carry away heat, it is important to make sure the refrigerant level is sufficient and system components are operational.

While vehicle air conditioners should be serviced annually, various warning signs may indicate problems. Signs of problems include:

• The system may fail to cool to the temperature desired.
• A musty smell may come out of the vents when the air conditioner is operating.
• Water on the vehicle floor.
• The air conditioner or engine making loud noises or running roughly when the air conditioner is in use.
• Engine overheating when the air conditioner is operating.

During servicing, the technician will examine the belts that operate the air compressor and will check for leaks in the hoses. If the refrigerant is low, the technician will likely top it off with R-134a, an environmentally friendly product that replaced R-12 (commonly known as Freon) in the late 1990s. For vehicles manufactured before 1995 that still use R-12, the inspector may recommend converting the air conditioning system so substitute refrigerants such as R-134a can be used. These substitutes are less expensive, which may save motorists money.

Besides servicing the air conditioner, the technician may change the cabin air filter, which removes pollen, dust, cigarette smoke and smog from the vehicle interior. A clogged filter may allow bacteria to grow inside the heating and ventilation system, which could affect passengers' health and inhibit the flow of air. According to Walker, the cabin air filter should be replaced once a year or every 15,000 miles--or every 7,500 miles if smokers frequently ride in the vehicle or driven in areas with high pollen levels.

Although operating the air conditioner will cause the vehicle to consume more fuel, driving with the windows down at higher speeds could result in greater fuel consumption due to increased drag. When outdoor temperatures are not too warm, motorists may want to conserve fuel by turning off the air conditioner when driving in slow traffic.

• Don't drive at high speeds with windows down, this results in greater fuel consumption
• Don't forget to replace the cabin air filter at 15,000 miles or sooner to avoid bacteria
• Do drive with windows down on cooler days while driving in slower traffic
• Do use A/C during faster driving periods with windows up to consume less fuel.