My A/C system is leaking refrigerant. How can I find the leak?
The two most common ways to find a leak are to:
Visually inspect the system for tell tale oil stains
When refrigerant leaks from the system, it immediately evaporates into thin air leaving no trace except possibly the compressor oil residue that leaks out with it. Wet oily areas around hose connections and fittings and/or greasy streaks radiating outward around the compressor clutch or on the underside of the bonnet just above the compressor are good visual clues to the location of the leak.
Fluorescent Dye is added to the system, the presence of the coloured dye around hose connections and fittings after the system has been run for a period of time are indications of escape. Leak detecting dyes will often reveal tiny leaks that might escape visual detection. Some are fluorescent and require illumination with a special light before you can see them. Despite this, even dyes can fail to determine the location of a leak if the leak is in the evaporator (located inside the heater/defroster plenium under the dash) or in a hard-to-observe or hidden location.
Use an electronic leak detector
Most professionals use an “electronic” leak detector that reacts to the presence of refrigerant in the air. Such detectors are extremely sensitive and can detect leaks as small as 1/4 oz. of refrigerant per year!