How to Select Replacement AC Compressor

The AC compressor is an important part of keeping a car interior cool.

The air conditioner compressor is the heart of any car's interior climate control, especially when it comes to interior cooling. Having the compressor suddenly fail can spell disaster during the hot summer months. Replacing an AC compressor can be a rather expensive task, with many compressors starting in the $300 to $400 range. The labor cost estimate alone can give anyone pause, which is why it's important to select a replacement that will last for as long as the vehicle itself.

Instructions

1. Find out if your vehicle uses R12 or R134a before searching for an AC compressor. Most vehicles made during the early 1990s and afterward use R134a as an alternative to the older and less environmentally friendly R12. The mineral oil used in R12 is not compatible with the oil used with R134a, making a direct mix or swap without a complete evacuation a potentially destructive proposition.

2. Consult an automotive parts database to determine the exact AC compressor model needed for your vehicle. In many cases, a good database from a well-known automotive parts chain can tell you exactly what type of compressor your vehicle needs. Many vehicles require a certain type of compressor that can handle the higher operating pressures of R134a. Older vehicles with lightweight compressors designed for R12 may have to be replaced with heavier units that can handle R134a.

3. Decide if you want to go with a new, refurbished or used AC compressor. The best compressor to use is a brand-new or re-manufactured unit that is manufactured by an original equipment manufacturer (OEM) for your vehicle. There are also non-OEM units available at a lower price, but the quality and longevity may not be as good. A used AC compressor from a junkyard may be fraught with oil contamination, requiring a rebuild that may cost significantly more than a new or re-manufactured unit.

Tips & Warnings

• If you choose to convert from an R12 compressor to an R134a unit, you may also have to change out some of the hoses and fittings on your AC lines as part of a retrofit procedure. The lines also have to be purged of the mineral oil used with R12 to properly use the PAG oil in R134a.

• Do not mix R12 refrigerant with R134a. The two refrigerants use different oils that are incompatible with one another. Mixing these oils can cause the compressor to fail prematurely.

References

• AA1Car: R12 to R134A Refrigerant Retrofit