Leaks, Determining Via Pressure Test (With Forming Gas) And Leak Detector Or Leak Detection Spray

Special tools and workshop equipment required 

• Air Conditioning Service Unit R744 :VAS581009 
• Pressure Regulator :VAS584005 
• Gas Leak Detector :VAS523003 

  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

• Commercially available leak detection spray
• Commercially available forming gas container 95/5 (container pressure at least 85 bar (1, 232.82 psi))

Leak Detection

If the vehicle, cannot be lifted high enough on the hoist due to the allocation of the service connections and the length of the service connections, the pressure test can be interrupted, for the length of the leak detection on the underbody. The service hoses can be separated from the vehicle and the leaks can be determined. The pressure test can be continued or ended.

• The refrigerant circuit is completely assembled.

-- De-energize the high-voltage system now. Refer to [For engine(s) EBRA] High-Voltage System, De-Energizing .

-- Use the Vehicle Diagnostic Tester to perform the function "Refrigerant circuit, charging/evacuating/flushing".

• The Vehicle Diagnostic Tester must not be disconnected from the vehicle during this process.
• It is absolutely necessary to perform the "Refrigerant circuit, charging/evacuating/flushing" function with the Vehicle Diagnostic Tester so that all of the refrigerant circuit valves are opened.

-- Discharge the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING  .

-- Open the service coupling on the A/C Service Station until the green markings can be seen.

-- Select the "external pressure test" at the A/C service station.

• Maximum pressure test setting at 85 bar (1, 232.82 psi).

-- Connect the Air Conditioning Service Unit R744 :VAS581009  , the Pressure Regulator :VAS584005  and a container filled with forming gas according to the respective operating instructions. Refer to the Operating Instructions.

-- Make sure the Pressure Regulator is closed so that no gas escapes when opening the container filled with forming gas. Refer to the Pressure Regulator Operating Instructions.

-- Slowly increase the refrigerant circuit pressure to a maximum of 15 bar (217.56 psi).

-- Find the location of the leak by listening for the sound of venting gas.

• In the event that the refrigerant circuit pressure decreases drastically and no gas leak detection is possible, then it is possible to fill forming gas through the A/C service station and to continue the leak detection.

-- End the "external pressure test" using the A/C service station.

-- Repair any leaks.

Further steps if the leak could not be determined by checking for noises:

If the leak is too large to determine it by checking for noises, then the external pressure test must be continued. The leak must be determined by using the Gas Leak Detector :VAS523003  and leak detection spray.

-- Continue the "external pressure test" using the A/C service station.

-- Slowly increase the refrigerant circuit pressure to a maximum of 85 bar (1, 232.82 psi).

• If the pressure falls below 80 bar (1, 160.3 psi) and the leak was not found, fill forming gas through the A/C service station and continue the leak detection.
• If the pressure relief valve on the Pressure Regulator :VAS584005  is triggered, immediately reduce the output pressure at the Pressure Regulator until the valve closes again.

-- Do not work in a drafty area in order to avoid any incorrect measurements.

-- Use compressed air to regularly clean the front of the vehicle.

-- Locate leaks using the Gas Leak Detector :VAS523003  and leak detection spray.

-- Use the Vehicle Diagnostic Tester to perform the function "Refrigerant circuit, charging/evacuating/flushing".

-- End the "external pressure test" using the A/C service station.

-- Repair any leaks.

-- After completing the leak detection procedure, clean the areas where the leak detection spray was applied.