R-12 Systems

Testing the refrigerant system for leaks is one of the most important phases of troubleshooting. One or more of the methods outlined will prove useful in detecting leaks or checking connections if service work is performed. Before beginning any leak test, attach a manifold gauge set and note pressure. If little or no pressure is indicated, a partial charge must be installed. Check all connections, compressor head gasket, oil filler plug and compressor shaft seal for leaks. Prior to performing any leak test, prepare the vehicle as follows:
1. Attach suitable gauge manifold to system and observe pressure readings.
2. If little or no pressure is indicated, 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.