Car A/C Leak Testing Procedure
Different leak detection methods should be applied under the appropriate conditions. An oil stain test is only appropriate for R12 systems. If a system has no refrigerant in the system at all then OFN pressure testing with bubble spray should be selected. Often the leak will be quite large and easy to find. If the system has a low residual pressure then UV test to find an appropriate area where the leak may have occurred. Run the A/C system for a short period if possible and place the electronic leak detection (sniffer) tester around the system concentrating on areas where UV dye was found.Vacuum testing is particularly useful during servicing and applying a deep vacuum for moisture removal is important. Vacuum testing should never be used to test the correct fitment of components. OFN should be applied to the system to ensure that the system is leak free and components and seals have been correctly applied during the repair procedure.