Commodore as notorious for leaking every where in the A/C system, many times it can be found by green dry leaking oil and giving a witness mark where to find the leak

Client already annoyed at having to carry out Regassing 3 Times it was sent to the experts in vehicle service and repairs

Air Con leak testing – the only way

The R134a has charge was removed and a trace nitrogen gas purged into the system, a clever sniffer wand is then used to find the source of leaks, after having a visual inspection over the system oil marks could not be found the charge ports on the high and low side removed and it was found that a simple charge port valve leaking, causing all the headache

Moral of the story is that repairs can be simple they don’t always mean the dash board has to come out.
Testing will always win before replacing parts

Trust in a repairer that tests before replaces parts.