Changing the A/C system in an old Pontiac to be compatible with the new coolant is essentially a matter of replacing the old Pontiac A/C compressor with one that is able to handle the higher pressures involved.

Why bother? The coolant used in new systems, R-134a, is safer for humans and the planet. Also, since the old refrigerant has been outlawed, replacing it has become nearly impossible.

Things to Keep in Mind When Retrofitting a Pontiac A/C Compressor

When refitting an R-12 car air conditioning system, keep a few things in mind:

• The newer systems are smaller and hold less coolant, so pay attention to the coolant levels recommended by the manufacturer.
• New compressors use clutches that use metric measurements to make it impossible to attach the part to an older system accidentally. Replacing the clutch will be necessary.
• New compressors are often designed for retrofitting and can be installed in a car A/C system designed for R-12 or R-134a coolant, which makes upgrading easier.

Another thing to remember is that R-12 and R-134a systems use different types of lubricating oil. The mineral oil used in the R-12 system is not compatible with R-134a coolant. Flushing the entire system is recommended to remove as much of the old oil as possible before the new refrigerant and oil are added. Remember, purging R-12 coolant must be done by a professional.

A-Air is an online retailer that specializes in auto A/C systems. The inventory at A-Air includes thousands of new and rebuilt parts, including compressors compatible with both R-12 and R-134a systems for 15 different Pontiac auto models from the past two decades.