Leak Detectors

Typical Leak Detector:

R-12 and R-134a systems use different leak detectors. An R-12 leak detector will not detect R-134a leaks (R-134a molecules are much smaller than R-12 molecules). However, an R-134a leak detector will detect R-12 leaks (be sure to follow the manufacturer's instructions carefully to avoid contamination).

An R-12 leak detector uses a very sensitive pickup which indicates the presence of Freon: a white light illuminates or a warning buzzer sounds.

Always check for leaks with the engine off. The radiator fan of a running engine may circulate the leaking refrigerant, making the leak point difficult to locate. (Initially, however, you should operate the engine for two minutes, to blow away any pools of refrigerant.) The A/C system should be charged with a normal amount of refrigerant.

To check the evaporator, put the leak detector probe in one of the housing drains.

An R-134a leak detector has been tested and approved by BMW, TIF 5550. It automatically calibrates when turned on, and it detects leaks as small as 0.40 oz. of R-12 or R-134a per year.

BMW does not recommend the use of dyed refrigerant for finding a leak. The dyes can sometimes impair system operation and may damage the interior fabrics of the car.