Cars with air conditioning systems manufactured before 1995 used R-12 Freon, a refrigerant that is considered by many to be harmful to the ozone layer and is no longer produced in most countries. The current industry standard, R-134a, is an efficient absorber and carrier of heat that lacks the ozone-damaging properties associated with R-12. Contrary to popular belief, most cars originally equipped with R-12 can be converted to 134a and still keep you just as cool. Here are some basic tips to convert your classic Ford muscle car to 134a.
Recommended steps to converting your Ford R12 air conditioning system to 134a.
Systems w/o Suction Valve Minimum Requirements
- Change or restore the filter drier.
- Drain the compressor oil and recharge with 134a-compatible oil. (PAG or Ester Oil)
- Ensure that the system is clean and free of contaminants (Depending on the component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air-conditioning flushing agent)
- Replace or restore all rubber hoses with barrier hoses.
- Install 134a charge port adapters.
- Charge with 134a between 70-80% of the original R12 charge amount.
- Replace any o-rings with 134a compatible.
HELPFUL HINTS
- Ignore the sight glass. A properly charged 134a system will likely show bubbles in the sight glass.
- The typical 134a charge rate will be approximately 70-80% of the factory R12 charge amount.
Systems w/POA Valve (aka Suction Throttling Valve & By-Pass Valve) The POA Valve is installed on the evaporator, near the firewall.
Minimum Requirements
- Change or restore the filter drier.
- Drain the compressor oil and recharge with 134a-compatible oil. (PAG or Ester Oil)
- Ensure that the system is clean and free of contaminants (Depending on the component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air-conditioning flushing agent)
- Replace or restore all rubber hoses with a barrier hose.
- Install 134a charge port adapters.
- Send POA Valve in to be calibrated.
- Charge with 134a between 70-80% of the original R12 charge amount.
- Replace any o-rings with 134a compatible.
HELPFUL HINTS
- Ignore the sight glass. A properly charged 134a system will likely show bubbles in the sight glass.
- The typical 134a charge rate will be approximately 70-80% of the factory R12 charge amount.
Systems w/Accumulator The accumulator is most often installed on the evaporator, near the firewall, but occasionally found in the middle of the suction hose between the evaporator and the compressor.
Minimum Requirements
- Change or restore the accumulator.
- Drain the compressor oil and recharge with 134a-compatible oil. (PAG or Ester Oil)
- Ensure that the system is clean and free of contaminants (Depending on the component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air-conditioning flushing agent)
- Replace or restore all rubber hoses with a barrier hose.
- Install 134a charge port adapters.
- Charge with 134a between 70-80% of the original R12 charge amount.
- Replace any o-rings with 134a compatible.
HELPFUL HINTS
- Ignore the sight glass. A properly charged 134a system will likely show bubbles in the sight glass.
- The typical 134a charge rate will be approximately 70-80% of the factory R12 charge amount.
If you have questions about converting your classic Ford air conditioning system from R12 to R134a, feel free to contact Classic Auto Air for more information.
Will the older Tecumsah or York compressors be able to handle the increased head pressures of R134 with a new shaft seal kit?