System Leak Checking

WARNING:
- R-134a SERVICE EQUIPMENT OR VEHICLE A/C SYSTEM SHOULD NOT BE PRESSURE TESTED OR LEAK TESTED WITH COMPRESSED AIR. MIXTURE OF AIR and R-134a CAN BE COMBUSTIBLE AT ELEVATED PRESSURES. THESE MIXTURES ARE POTENTIALLY DANGEROUS AND MAY RESULT IN FIRE OR EXPLOSION CAUSING INJURY OR PROPERTY DAMAGE.

- AVOID BREATHING A/C REFRIGERANT AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY IRRITATE EYES, NOSE AND THROAT USE ONLY APPROVED SERVICE EQUIPMENT MEETING SAE REQUIREMENTS TO DISCHARGE R-134a SYSTEM. IF ACCIDENTAL SYSTEM DISCHARGE OCCURS, VENTILATE WORK AREA BEFORE RESUMING SERVICE.

If the A/C system is not cooling properly, determine if the refrigerant system is fully charged with R-134a. This is accomplished by performing a system Charge Level-Check or Fill. If while performing this test A/C liquid line pressure is less than 207 kPa (30 psi) proceed to Empty Refrigerant System Leak Test. If liquid line pressure is greater than 207 kPa (30 psi) proceed to low refrigerant level leak test. If the refrigerant system is empty or low in refrigerant charge, a leak at any line fitting or component seal is likely A review of the fittings, lines and components for oily residue is an indication of the leak location. To detect a leak in the refrigerant system, perform one of the following procedures as indicated by the symptoms.

Empty Refrigerant System Leak Test
1. Evacuate the refrigerant system (minimum evacuation time of 15 min.) to the lowest degree of vacuum possible (approx. 28 in. Hg.). Determine if the system holds a vacuum for at least 15 minutes after pump is off. If vacuum is held, a leak is probably not present. If system will not maintain vacuum level, proceed with this procedure.
2. Prepare a 0.284 Kg. (10 oz.) refrigerant charge to be injected into the system.
3. Connect and dispense 0.284 Kg. (10 oz.) of refrigerant into the evacuated refrigerant system.
4. Proceed to Step 2 of Low Refrigerant Level Leak Test.

Low Refrigerant Level Leak Test
1. Determine if there is any (R-134a) refrigerant in the system. Use the scan tool (DRB III�) partial charge test or pressure gauge liquid line temperature partial charge check. See system charge level check or fill for procedure.
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. This is done by allowing the engine to run for five minutes with the system set to the following:
- Transaxle in Park
- Engine Idling
- A/C Controls Set in 100 percent outside air
- Blower switch in the high A/C position
- A/C in the ON position
- Open all windows

CAUTION: A leak detector designed for R-12 refrigerant may not detect leaks in a R-134a refrigerant system. Check specifications on leak detector.

4. Shut off the vehicle and wait 2 to 7 minutes. Then use an Electronic Leak Detector that is designed to detect R-134a type refrigerant and search for leaks. Fittings, lines, or components that appear to be oily usually indicates a refrigerant leak. To inspect the evaporator core for leaks, insert the leak detector probe into the drain tube opening or a heat duct.

If a thorough leak check has been completed without indication of a leak, proceed to System Charge Level.

NOTE: If leak is not detected but known to exist, further diagnosis may be necessary using a refrigerant dye and the recovery machine. Refer to recovery machine instructions for proper dye injection procedures.