A/C System Maintenance


To keep you your air-conditioning and heating system operating at top efficiency, periodically perform these maintenance tasks.

Warning: The air-conditioning system is under high pressure. Do not loosen any fittings or remove any components until after the system has been discharged. Air-conditioning refrigerant must be properly discharged into an EPA-approved container at an automotive air-conditioning repair facility or dealer service department. Always wear eye protection when disconnecting air-conditioning system fittings.

Note: The following are general instructions. Always refer to a repair manual written specifically for your car, truck, van or SUV when performing any type of maintenance work.

Check the compressor drive belt. It has deteriorated or is worn, replace it according to your vehicle-specific repair manual.

Check the tension of the drive-belt. Adjust if necessary (see your repair manual).

Check the hoses in the system for deterioration, cracks, bubbles and hard spots. Also inspect the hoses and their fittings for oil bubbles and seepage. If you find evidence of damage, wear, or leaks, replace the hose(s).

Inspect the fins on the condenser for dead bugs, leaves and other debris. To clean the condenser, use a "fin comb" or compressed air.

Check the evaporator housing drain tube for blockages.

Tip: To avoid hardening of the air-conditioning system seals, it is recommended that you operate your a/c system at least once a month. This is especially important during the winter months.

Check the refrigerant charge. A low charge is the most common cause of poor cooling. If you notice a sudden drop in your cool air output, perform the following temperature check.

Warm up the engine to normal operating temperature.

On your dashboard, move the a/c temperature selector to the coolest setting. Adjust the blower motor at the highest setting. To avoid recycling of the passenger compartment air, and therefore to avoid the a/c unit shutting off, open all the vehicle doors.

Check the a/c compressor outlet and inlet lines. If the inlet line feels cool and the outlet line feels warm, the system is charged adequately.

Place a thermometer in one of the dashboard vents, preferably the one that is closest to the evaporator. Run the system until the thermometer indicates between 40 and 45 degrees Fahrenheit. If the outside air is temperature is very high, for example 100-plus degrees, the temperature of the air at the vent may be as high as 60 degrees F, which is in an acceptable range. In general, the a/c air temperature should be 30 to 50 degrees cooler than the outside air. Note: Also monitor the outside humidity. High humidity in the air also lowers the temperature of the cool air the system is putting out.

If your air-conditioning system is not putting out enough cool air, you can add refrigerant. Refer to your physical or online manual for instructions. Or have a professional a/c repair facility or dealership add it for you.

Remember: effective a/c operation is not only a comfort factor - it can be a matter of health, especially for the sick, the very young and the elderly. Make sure your system operates correctly and efficiently, for the benefit of you and your passengers.