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 345 kPa (50 psi) proceed to System Empty procedure. If liquid line pressure is greater than 345 kPa (50 psi) proceed to 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.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, proceed to Step 2.
- Prepare and dispense 0.284 kilograms (10 ounces) of R-134a refrigerant into the evacuated refrigerant system.
- Proceed to Step 2 of System Low procedure.
- Determine if there is any R-134a refrigerant in the system.
- Position the vehicle in a wind free work area. This will aid in detecting small leaks.
Bring the refrigerant system up to operating temperature and pressure. This is done by allowing the engine to run for five minutes with the A/C system set to the following:
- Transmission in Park or Neutral (depending on application) with parking brake set Engine idling
- Mode control set to the fresh air position
- Blower control set to the high speed position
- Temperature control set to full cold position
- A/C set to the ON position
All windows open
CAUTIONA leak detector only designed for R-12 refrigerant will not detect leaks in a R-134a refrigerant system.
- 4. 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 DaimlerChrysler approved refrigerant dye.