A/C refrigerant system, leak testing

Use halogen leak detector Hitec HI400A-TEL or equivalent to check for refrigerant leaks.
Refrigerant gas dissipates very quickly. Avoid drafty or windy areas when checking for leaks.
Some refrigerant leaks are apparent by refrigerant oil deposits on or near leak location. Confirm by using leak detector.
If the refrigerant system is discharged (empty), charge system with approx. 100 g (3.5 oz) of refrigerant in order to check for leaks.

Check refrigerant system for leaks following leak detector manufacturer's instructions.

Fig 1: Checking Refrigerant Leaks By Passing Detector Probe Under Suspected Leaking Components
Courtesy of AUDI OF AMERICA, INC.
Check for refrigerant leaks by passing detector probe under suspected leaking components.

NOTE: Refer to leak detector manufacturer's instructions.