Oil Injection and Refrigerant Charging

When using the ACR4 Recovery Station, always close both low and high side manifold gauge valves on the ACR4 control panel as soon as the vacuum pump cycle is complete. To inject oil from the oil bottle on the back of the ACR4, simply open the oil injection valve; oil automatically flows through the high side service hose and into the vehicle without entering the manifold gauge assembly.

^ ALWAYS CHARGE REFRIGERANT THROUGH THE HIGH SIDE ONLY. General Motors requires high side charging on all GM vehicles, and the flow of liquid refrigerant through the high side is necessary to wash any remaining oil in the high side service hose into the vehicle.

^ There are several oil and tracer dye injectors on the market that are designed to be installed between the ACR4 and the low side service hose. DO NOT USE THIS TYPE OF INJECTOR.

^ Oil and tracer dye injectors designed to connect directly to the vehicle's low side service port can be used. However, you must run the vehicle's A/C system long enough to ensure the oil or dye is distributed evenly throughout the A/C system prior to recovering refrigerant from the vehicle.

^ Indications that technicians are incorrectly injecting oil and leak dye are:

- Large amounts of oil or dye drained from the oil separator after recovery.

- Vacuum pump oil level above the sight glass or tinted the color of dye.

- Large amounts of oil and dye residue covering ACR4.

- Liquid flooding of the PureGuard 2.

This occurs because oil and dye intended for the vehicle's A/C system is trapped in the service hose. The next time refrigerant recovery is performed, the oil and dye are drawn back into the ACR4.

^ To ensure the vehicle receives the correct refrigerant charge, the hose clearing procedure must be performed every time a vehicle is charged. Refer to the ACR4 manual for this procedure. Failure to do so will leave a significant amount of liquid refrigerant in the ACR4 service hose.

^ Disconnect the high and low side service hoses from the vehicle as soon as NC service is complete. Failure to disconnect the couplers will allow the PureGuard 2 to continue to take small samples of refrigerant and test it. Over time, the charge level in the vehicle will decrease to a point where it will be necessary to recharge the system again due to loss of refrigerant.

^ An unsuccessful charging procedure occurs when the refrigerant does not completely transfer from the ACR4 tank into the vehicle.

Unsuccessful charging can be avoided by running the vacuum pump for the full 15-minute vacuum cycle and charging the vehicle as soon after the vacuum cycle as possible. The refrigerant is recycled during the vacuum cycle building up heat and pressure which completely forces the entire charge into the vehicle.