A/C System Leak Test

The following instructions refer to an electronic type Refrigerant Leak Detector for use with R134a, which is the safest and most sensitive.


CAUTION: When a major repair has been carried out, a leak test should be carried out using an inert gas (see below).


1. Place the vehicle in a well ventilated area but free from drafts, as leakage from the system could be dissipated without detection.
2. Follow the instructions issued by the manufacturer of the particular leak detector being used.
3. Commence searching for leaks by passing the detector probe around all joints and components, refrigerant gas is heavier than air.
4. Insert the probe into an air outlet of the evaporator or into the evaporator drain tube. Switch the air conditioning blower on and oft at intervals of ten seconds. Any leaking refrigerant will be gathered in by the blower and detected.
5. Insert the probe between the magnetic clutch and compressor to check the shaft seal for leaks.
6. Check all service valve connections, valve plate, head and base plate joints and back seal plate.
7. Check the condenser for leaks at the pipe unions.
8. If any leaks are found, the system must be discharged before rectification.
9. Rectify any leaks and recheck for leaks during evacuation prior to charging.

Leak test using inert gas

Use Nitrogen or Helium gas.
1. Connect gas line to recharging station.
2. Pressurize system to 3 bar.
3. Carry out leak test as above.