Checking Refrigerant Leaks
PRELIMINARY CHECKPerform a visual inspection of all refrigeration parts, fittings, hoses, and components for signs of A/C lubricant leakage, damage and corrosion.
Precautions For Handling Leak Detector:
PRECAUTIONS FOR HANDLING LEAK DETECTOR
When performing a refrigerant leak check, use a J39400 A/C leak detector or equivalent. Ensure that the instrument is calibrated and set properly per the operating instructions.
The leak detector is a delicate device. In order to use the leak detector properly, read the operating instructions and perform any specified maintenance.
Other gases in the work area or substances on the A/C components, for example, anti-freeze, windshield washer fluid, solvents and cleaners, may falsely trigger the leak detector. Make sure the surfaces to be checked are clean. Do not allow the sensor tip of the detector to come into contact with any substance. This can also cause false readings and may damage the detector.
1. Position probe approximately 5 mm (3/16 in) away from point to be checked.
2. When testing, circle each fitting completely with probe.
3. Move probe along component approximately 25 to 50 mm (1 to 2 in)/sec.
CHECKING PROCEDURE
To prevent inaccurate or false readings, make sure there is no refrigerant vapor or tobacco smoke in the vicinity of the vehicle. Perform the leak test in calm area (low air/wind movement so that the leaking refrigerant is not dispersed.
1. Charge the system with the specified amount of refrigerant.
2. Run the engine with the A/C compressor ON for at least 2 minutes.
3. Stop engine.
Checking Refrigerant Leaks-Checking Procedure:
Refrigerant leaks should be checked immediately after stopping the engine. Begin with the leak detector on the high pressure line. The pressure in the high pressure line will gradually drop after refrigerant circulation stops and pressure in the low pressure line will gradually rise, as shown in the graph. Leaks are more easily detected when pressure is high.
4. Conduct the leak test from the high side to the low side at points (a) through (m). Refer to Refrigerant lines.
Perform a leak check for the following areas carefully. Glean the component to be checked and move the leak detector probe completely around the connection/component.
^ Compressor
Check the fitting of high and low pressure hoses, relief valve and shaft seal.
^ Liquid tank
Check the pressure switch, tube fitting and the fusible plug mounts.
^ Service valves
Check all around the service valves. Ensure service valve caps are secured on the service valves (to prevent leaks).
^ Cooling unit
Turn blower fan on "High" for at least 15 seconds to dissipate any refrigerant trace in the cooling unit. Insert the leak detector probe into the drain hose immediately after stopping the engine. (Keep the probe inserted for at least 10 seconds.)