R-12 Systems

Testing the refrigerant system for leaks is one of the most important phases of troubleshooting. Several types of leak detectors are available that are suitable for detecting A/C system leaks. One or more of the following procedures will prove useful for detecting leaks and checking connections after service work has been performed. Prior to performing any leak test, prepare the vehicle as follows:
1. Attach a suitable gauge manifold to system and observe pressure readings.
2. If little or no pressure is indicated, the system must be partially charged.
3. If gauges indicate pressure, set engine to run at fast idle and operate system at maximum cooling for 10-15 minutes, then stop engine and perform leak tests.

EMPTY REFRIGERANT SYSTEM LEAK TEST

CAUTION: Review Safety Precautions and Warnings.

1. Evacuate the refrigerant system to the lowest degree of vacuum possible.
2. Prepare a 10 oz. refrigerant (R-12) charge to be injected into the system.
3. Connect and dispense 10 ozs. of refrigerant into the evacuated refrigerant system.
4. Proceed to step two of Low Refrigerant Level Leak Test.

Testing For A/C Leaks:

LOW REFRIGERANT LEVEL LEAK TEST

Caution: Review Safety Precautions and Warnings.

1. Using the refrigerant level sight glass, determine if there is any (R-12) refrigerant in the system.
2. Position the vehicle in a wind free work area, This will aid in detecting small leaks.
3. Bring the refrigerant system up to operating temperature and pressure by allowing the engine to run for approximately five minutes.
4. With the engine not running, use an Electronic Leak Detector (or equivalent) and search for leaks. Fittings, lines, or components that appear to be oily usually will indicate a refrigerant leak. To inspect the evaporator core for leaks, it is possible to insert the leak detector probe into the recirculating air door opening.