Refrigerant leaks can be a common servicing issue that mechanics see from clients who bring their vehicles into the auto shop.  Leaks can be caused by various problems, and a leak detector is a great way to test if this is even the issue to begin with, prior to carrying out further troubleshooting.

Before getting out the leak detector, however, there are a few things it may be best to do first.  An initial service to perform is to examine the various hoses, fittings, compressor and condensor to see if you find a build up or residue on these (or even green if Ultraviolet dye has been added to the system).

If oil is what you encounter on any of the parts, try to figure out whether this oil is coming from the component or somewhere else in the air condition system.  Oil on the compressor could actually be a leaky power steering pump, whereas oil on the compressor may be just that - spilled oil.

If, after all examinations have been completed, you still find the need to continue testing, leak detectors will assist you most easily in this process.