By Warren McCord

Q: My vehicle’s air-conditioning is not keeping the interior as cool as it did last year. Should I just have more refrigerant put into the system?

A: No. There are many reasons other than lack of coolant that could explain why the air conditioner may not be working correctly.

For example, temperature controls may not be functioning as they should, which has nothing to do with the system charge or refrigerant level. If the refrigerant level is low, there is most likely a leak somewhere in the system. This leak allows air and moisture to get into the system and causes a loss of refrigerant. If the cause of the leak is not repaired and the air and moisture are not purged from the system, the refrigerant will mix with the moisture and create hydrochloric acid. This acid will deteriorate the components of the system from the inside out.

If your air-conditioning system is not performing correctly, it is important to have it examined by a professional with the correct equipment to both diagnose and repair the system defect.

The most critical piece of equipment required is a refrigerant identifier. There are only two types of refrigerant that should be in an automobile’s air-conditioning system: R-12 or R-134A. If anything else is put into the system, it is considered contaminated and must be removed from the system and handled as toxic waste. If your system is using R-12 and another type of refrigerant is added, there is potential for serious damage to your vehicle.

There is also equipment needed to check the operation of the air-conditioning system that is dedicated to either R-12 or R-134A, as well as equipment that checks for external leakage of the refrigerant and determines the source of the leak.

Be aware that many quick lubes and repair facilities may be putting the wrong refrigerant into automotive air-conditioning systems because of a lack of knowledge, training or correct equipment. Don’t hesitate to ask if a shop is using the correct equipment before they work on your vehicle.

Warren McCord is an ASE certified master technician and owner of Dean’s Automotive Inc., 2037 Old Middlefield Way, Mountain View. For more information, call 961-0302 or e-mail McCord at djmmccord@att.net.