Refrigerant System Leaks
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 and possible serious or fatal injury.
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 refrigerant charge is empty or low, a leak in the A/C system is likely. Visually inspect all A/C lines, fittings and components for an oily residue. Oil residue can be an indicator of an A/C system leak location.
The only way to correctly determine if the A/C system is fully charged with refrigerant to perform the A/C Performance Test. Refer to A/C PERFORMANCE TEST .
Connect a suitable manifold gauge set and determine if the static A/C system pressure is above or below 345 kPa (50 psi). If the pressure is less than 345 kPa (50 psi), continue with next step.
System Empty
-- 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, continue with next step.
-- Prepare and dispense 0.284 kilograms (10 ounces) of R-134a refrigerant into the evacuated refrigerant system.
System Low
-- Position the vehicle in a wind free work area. This will aid in detecting small leaks.
-- Operate the HVAC system with the engine at idle under the following conditions for at least 5 minutes.
- Doors or windows open.
- Transmission in park.
- HVAC controls set to outside air, full cool, panel mode, high blower and with A/C compressor engaged.
- If equipped with rear heating-A/C system, set rear controls to full cool and high blower.
A leak detector only designed for R-12 refrigerant will not detect leaks in an 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. A dye for R-134a is available to aid in leak detection. Use only approved refrigerant dye.