Cadillacs are equipped with air conditioning systems that use circulated coolant and fans to lower the ambient interior temperature. These systems can leak coolant as the gaskets degrade and may require recharging to discover the source of the leak. The average weekend mechanic can recharge the A/C system on a Cadillac in about 30 minutes.
Evacuate the air conditioning system professionally by taking it to an oil change facility or garage. This removes any debris or contaminants from the lines, condenser, evaporator and compressor. The refrigerant could be hazardous to the atmosphere so it cannot be discharged openly. The garages are typically compensated for collecting the coolant.
Connect a can of coolant to the valve kit by turning the can clockwise on the bottom of the valve's screw adapter. The needle inside the valve will puncture the can, pressurizing the valve and nozzle. This only applies if converting an R-12 system to a 134a system or charging a system manufactured with 134a. The R-12 coolant is no longer sold to consumers. Connect the nozzle to the low pressure side of the air conditioning system by pressing the valve's nozzle to the nipple on the low pressure coolant line or evaporator. Pull the nozzle's edge back and push it over the nipple, creating a seal.
Start the Cadillac and set the climate controls to the lowest temperature to start the air conditioning system. Open the valve and allow the system to extract the coolant from the can via vacuum. It will take about 10 minutes to empty a can; remember not to shake or turn the can while it is discharging. When the can is depleted, pull the nozzle from the low pressure nipple then turn the can counterclockwise on the valve to release it. Replace it with another can of coolant, or the compressor lubricant or UV dye, and repeat the procedure. Continue to allow the system to consume coolant until the can no longer empties, signaling the system is at capacity. Usually this takes three cans of coolant and one can of lube/dye. The 134a contains a small amount of lubricant, but adding additional cans can prolong the lifespan of the compressor.
Run the Cadillac for a few days, using the air conditioning system periodically. Check the engine compartment at night with the ultraviolet light for dye marks, usually bright green. This will indicate a leak in the A/C system and the cause for losing coolant. Air conditioning refrigerant does not get \"used up,\" and without leaking should last for years until mechanical parts fail and the system must be evacuated.
