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 property damage, personal injury or death.
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 Refrigerant System Charge Level test or by completely evacuating and recharging the A/C system.
If the A/C liquid line pressure is found to be less than 50 psi (345 kPa) while performing the Refrigerant System Charge Level test, proceed to the System Empty procedure below.If liquid line pressure is found to be greater than 50 psi (345 kPa), proceed to the System Low procedure.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.
- Evacuate the refrigerant system to the lowest degree of vacuum possible (approximately 28 in Hg.).
- Determine if the system holds a vacuum for 15 minutes.
- If vacuum is held, a leak is probably not present.
- If system will not maintain vacuum level, proceed to next step.
- Prepare and dispense 10 ounces (0.284 kilograms) of R-134a refrigerant into the evacuated refrigerant system and proceed to the System Low procedure.
- Position the vehicle in a wind free work area. This will aid in detecting small leaks.
- Operate the heating-A/C system with the engine at idle under the following conditions for at least five minutes.
- Doors or windows open
- Transmission in Park
A/C-heater controls set to outside air, full cool, panel mode, high blower and with A/C compressor engaged
WARNINGA leak detector only designed for R-12 refrigerant will not detect leaks in a R-134a refrigerant system.
- Shut the vehicle Off and wait 2-7 minutes. Then use an electronic leak detector that is designed to detect R-134a refrigerant and search for leaks. Fittings, lines or components that appear to be oily usually indicate a refrigerant leak.
To inspect the A/C evaporator for leaks, insert the leak detector probe into the drain tube opening or an air outlet.
NOTEA dye for R-134a is available to aid in leak detection. Use only DaimlerChrysler approved refrigerant dye.