Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Filling UV-Leak Detection Additive When The Refrigerant Circuit Is Full
If leak detection fluid was filled already in a refrigerant circuit for an earlier repair, note the following: only add new leak detection additive if the refrigerant oil will be replaced. If only a portion of refrigerant oil was replaced, only top-off with a corresponding amount of leak detection fluid as well. For example, if 100 ml of refrigerant oil was replaced in a vehicle with 250 ml, add only 1 ml (cm3 ) of UV-leak detection additive.
A small quantity of UV-leak detection additive remains in the service connection. Carefully remove this residual amount so a leaking area is not detected erroneously upon a later leak detection.
The cartridge -A- contains 15.4 ml of UV-leak detection additive (one unit -B- corresponds to 2.5 ml).
-- Switch off ignition.
-- Remove sealing cap from service connection of low pressure side in refrigerant circuit.
-- Assemble - VAS 6201/1- item -1- with cartridge item -2- - VAS 6201/2-.
-- Insert tube - VAS 6201/8- into service coupling and open service coupling by screwing in handwheel. Hold the hose upward and tighten the handle of the hand pump just enough until the UV-leak detection additive starts to emerge from the tube, refer to item -7- under LEAK DETECTION ON REFRIGERANT CIRCUIT USING LEAK DETECTION SYSTEM VAS 6201 .
Make sure hand pump hose is completely filled with refrigerant.
-- Close service coupling and remove tube from locking mechanism.
-- Cover area around service connection on vehicle with foil or absorbent paper.
-- Connect filler unit to refrigerant circuit service connection on vehicle.
-- Open service connection by screwing in handwheel.
-- Turn the hand pump handle to add 2.5 + /- 0.5 ml (Milliliter= cm3 ) UV-leak detection additive in the refrigerant circuit (for a refrigerant circuit with a refrigerant oil quantity from 100 to 150 cm3 ).
-- Remove filling device from service connection.
-- Remove the rest of the UV-leak detection additive from the service connection, for example with absorbent paper.
-- Seal service connection with sealing cap.
-- If necessary, clean area around service connection using cleaning agents.
-- Affix sticker next to service connection with the note that leak detection fluid was added to this refrigerant circuit.
-- Start the A/C system.
A/C system must be operated for a minimum of 60 min. so that the additive distributes itself in the entire refrigerant circuit (compressor must be running). Depending on the size of the leak, it may become visible under UV light within that time.
Depending on the size and location of the leak, it can now last up to several days until enough refrigerant oil with additive flows out to determine definitely the leaking area.
-- Find the leak in the refrigerant circuit with the UV lamp VAS 6196/4 DETECTING LEAKS ON REFRIGERANT CIRCUIT USING UV LAMP VAS 6196/4 .
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.