Refrigerant Circuit, Locating Leaks with UV Lamp VAS 6196/4

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2009 Audi S4, 2009 Audi A4, 2008 Audi S4, 2008 Audi RS 4, and 2008 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Never look into UV lamp.

Never point UV lamp at other people.

NOTE:

After filling, the air conditioner must be operated for at least 60 min. to distribute the additive throughout the refrigerant circuit (compressor must run/be actuated).
Depending on the magnitude and location, it may take several days for sufficient refrigerant oil and additive to emerge to clearly identify the leak.
In the event of leaks at the evaporator, the additive may be washed out with the condensate and emerge via the condensate drain. As on most vehicles the evaporator is not accessible without considerable effort, checking the condensate drain for example can provide an indication of evaporator leakage. This does however require the additive to have been in the refrigerant circuit for a lengthy period (several days).
The safety goggles are not only designed to provide eye protection. They also make the additive more readily visible under UV light.
Depending on the accessibility of various parts of the refrigerant circuit, it may be necessary to remove certain vehicle components (e.g. bumper or air cleaner).

Fig 1: Refrigerant Circuit, Locating Leaks With UV Lamp VAS 6196/4

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Move vehicle to a less brightly lit area of the workshop (daylight or bright artificial lighting diminishes the effect of the UV light).

Check accessibility of various parts of the refrigerant circuit and remove components in area of refrigerant circuit which would block view of refrigerant circuit components (e.g. noise insulation and bumper).

Wear safety goggles to protect eyes.

Connect UV lamp to a 12V battery (vehicle battery). Take care to ensure correct polarity of connections.

Switch on UV lamp and illuminate components of refrigerant circuit. Locations at which leakage has resulted in the emergence of refrigerant, refrigerant oil and thus also leak detection additive show up under UV light (fluorescent).