Operation CHARM: Car repair manuals for everyone.

Optional

IMPROVED PERFORMANCE
To compensate for the higher vapor temperature of R-134a, the following may be needed to increase heat removal capacity and provide satisfactory cooling performance. Insufficient heat removal capacity may be indicated by high system pressures and warm outlet temperatures.

Improved Condenser
Older model tube and fin condensers should be replaced with more efficient Serpentine or Parallel flow style condensers. Smaller, reduced area condensers may need to be replaced with larger condensers to provide sufficient heat removal capacity.

NOTE: Cleaning the debris from in front of and behind the condenser can dramatically improve the systems cooling performance.

Improved Air Flow
Electric Pusher Fans - An auxiliary fan may be needed to provide additional airflow over the condenser.

More Efficient Fan Blades - Older vehicles may be equipped with 2 bladed fans. Replacing this type of fan with newer, more efficient multi-bladed fans will increase the airflow across the condenser, resulting in improved cooling performance.

Fan Clutch Operation - On belt driven fans, verify the fan clutch is operating properly. If there is any evidence of leakage from the clutch, it should be replaced. Replacing the clutch with a heavy duty model may be necessary to provide adequate airflow.

NOTE: Prior to installing new fans or fan clutches, verify that all fan shrouds and air dams are present and undamaged.

PREVENT LEAKAGE
Replace Non-Barrier Hoses - Because R-134a is made up of molecules which are much smaller than those in R-12, older non-barrier type hoses may leak when used with R-134a.

Early testing indicated that non-barrier type hoses would need to be replace during all R-134a retrofits. Recent testing has shown that the mineral oil used in lubricating the R-12 systems saturates the inner walls creating a sufficient barrier to prevent R-134 leakage.

NOTE: If the system is flushed, the oil saturation barrier will be removed and the non-barrier hoses will need to be replaced to prevent leakage.

Replace O-Rings and Seals - Any fitting which has been disturbed during the retrofit procedure should have the O-ring or seal replaced with one which is R-134a compatible. To prevent leakage, new O-rings and seals should be coated with mineral oil prior to installing.

INCREASED RELIABILITY
Compressor Replacement - The higher system pressures associated with R-134a could result in premature failures of worn compressors. Seals within the compressor may not be compatible with R-134a, resulting in seal failure and leakage.

NOTE: Always consult Technical Service Bulletins (TSB) prior to performing an R-134a retrofit. Some compressors are not compatible with R-134a and must be replaced.

Replace Receiver/Dryer/Desicant - Replacing the desicant helps assure a dry, moisture free cooling system. Replacing the Receiver/Dryer allows for removing any non-compatible mineral oil which may have collected in it.

Flush Condenser - If there has been a compressor failure or the compressor is worn flushing the condenser will remove any debris which might block refrigerant flow or cause further damage to the compressor.

NOTE: If any non-barrier hoses are flushed they will need to be replaced with barrier hoses to prevent refrigerant leakage.

SAFETY
If a vehicle is not equipped with a high pressure compressor shut-off switch, it is highly recommended to install one. Due to the higher operating pressures of R-134a it is very important to disengage the compressor prior to a component failure resulting from excessive pressure.