Check for leaks on the refrigerant circuit using.

• A/C system must have been operated for a minimum of 60 minutes so that the additive distributes itself in the entire refrigerant circuit (compressor must be running). Depending on the size of a leak, it may become visible within that time.

-- Move the vehicle into a slightly darker area of the workshop (with daylight or bright lighting the effect of the UV light is diminished).

-- Examine the refrigerant circuit components with UV light. Locations where UV leak detection additive has leaked out, will light up under UV light (they are fluorescent).

Tip

• Depending on the size and location of the leak, it can take several days until enough refrigerant oil with UV leak detection additive flows out to clearly determine the leaking area.
• Certain materials and their connections (for example, oxidation products on aluminum components, corrosion protection wax) also light up under UV-light.
• With leaks on the evaporator, leak detection additive is possibly washed off with condensation and flows out via the condensation water drain. Since the evaporator is not easily accessible on most vehicles, checking the evaporator drain may indicate if the evaporator is leaking. However, it is necessary for this purpose that additive has already been in the refrigerant circuit for a long period of time (for example, a few days).
• Only a little refrigerant oil will get onto certain places on the refrigerant circuit when A/C is being used (for example, on the top cover of the receiver/dryer attached to the condenser). If there is a leak at these locations, then it may possibly take a longer time until enough refrigerant with refrigerant oil and additive leaks at this location. It may be useful to use an electronic leak detector at these locations to find a leak. Refer to LEAKS, FINDING USING ELECTRONIC LEAK DETECTOR .