Leaks, Finding With Uv Leak Detection System: Notes

Certain leaks cannot or only with difficulty be found using an electric leak detection unit. To find these leaks a leak detection can be performed using the leak detection system. Refer to the Parts Information.

Refrigerant and refrigerant oil escape when there is a leak in the refrigerant circuit. Generally, this oil remains in the vicinity of the leaking area. A small amount of fluorescent fluid must be added into refrigerant circuit so that this oil becomes visible under UV light. This fluid (PAG oil with an additive that lights up under UV light) is added into the refrigerant circuit and distributes itself with the refrigerant oil when the A/C system is switched on.

A/C system must be 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 the leak, it may become visible under UV light within that time.

Refrigerant oil with additive that lights up under UV-light can be added directly with an open circuit or be pumped into a empty circuit using the A/C service station via the service connection.

If a leak detection additive is added via the service connection in the refrigerant circuit a small quantity of leak detection additive remains in the service connection. Carefully remove the residual amount so that upon later leak detection a leak is not incorrectly determined.

If a component in which leak detection additive has been added is being replaced on a circuit, always clean connection areas to other components thoroughly after assembling refrigerant circuit. This residue may be detected erroneously as leaking areas upon later leak detection.

Refrigerant oil and with it leak detection additive gets into the A/C service station when evacuating a refrigerant circuit. The refrigerant oil is separated from refrigerant in the oil separator from the A/C service station and removed from the A/C service station via the draining device. The refrigerant oil drained off must not be poured back in. It must be replaced with new refrigerant oil.

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 leak detection additive.

Certain materials and their connections (for example, oxidation products on aluminum components, corrosion protection growth, etc.) also light up under UV-light.

Depending on the version of your A/C service station leak detective can also be added directly using it, to do so pay attention to the notes in your A/C service station Owner's Manual. Refer to A/C service station Owner's Manual.

If a larger leak is found during evacuation, find it and repair it as described. Refer to LEAKS, DETERMINING USING VACUUM TEST WITH A/C Service Station , REFRIGERANT CIRCUIT, EVACUATING and LEAKS, DETERMINING WITH A PRESSURE TEST, WITH NITROGEN OR COMPRESSED AIR .

Only use UV-leak detection additive which approved for refrigerant R1234yf. Refer to the Parts Information.

The the major part of UV-leak detection additive is refrigerant oil, because for refrigerant R1234yf special refrigerant oil is required only UV-leak detection additive may be used in which this oil is the carrier liquid. The UV-leak detection additive developed for refrigerant R134a is not suitable for this reason.

For refrigerant circuits with refrigerant R1234yf and R134a different refrigerant oils (PAG oils) are used for this reason pay attention to the correct allocation of the leak detection additive (PAG oil with an additive that lights up under UV light).

Add the UV-leak detection additive to the refrigerant circuit using the A/C service station. Refer to Add the UV-Leak Detection Additive to the Refrigerant Circuit Using the A/C Service Station  below.

The quantity of UV-leak detection additive which is filled on a refrigerant circuit with a refrigerant oil quantity up to 150 cm³ is 3.0 ⁺ /_- 0.5 ml (cm³ ). If the refrigerant oil capacity in the refrigerant circuit is larger, then more UV leak detection additive must be added accordingly (for example, 5.0 ± 0.5 (cm³ ) for a refrigerant circuit with a refrigerant oil capacity of 250 cm ³ . When filling the UV-leak detection additive using an A/C service station the set quantity in the A/C service station can vary for this reason pay attention to the corresponding Owner's Manual. Refer to A/C service station Owner's Manual.

The actual refrigerant oil quantity in the refrigerant circuit can be found in the vehicle-specific repair information. Refer to TECHNICAL DATA [For transmission(s) 0BK] or TECHNICAL DATA [For engine(s) CTUA, CAED, CREH, CEUC, CTGE, CREC, CYNB, CPNB]

If UV-leak detection additive was filled already in a refrigerant circuit for an earlier repair, note the following: only add new UV-leak detection additive if the refrigerant oil will be replaced. If only a portion of the refrigerant oil was replaced, only add a proportionate amount of the UV-leak detection additive. For example, if 50 ml of refrigerant oil was replaced in a vehicle with 150 ml, add only 1.0 ml (cm³ ) of UV-leak detection additive.

Ignore items -1, 2 and 7- in the image.