General Information For Cleaning Refrigerant Circuit
Working on the refrigerant circuit with the A/C Service Station can normally be performed without needing to de-energize the high-voltage system.
To clean (flush) the refrigerant circuit specific components must be removed, before beginning the procedures de-energize the high-voltage system. Refer to the appropriate service information .
If it is suspected that chemicals were added to the refrigerant circuit to seal leaks, chemical substances to seal leaks in the refrigerant circuit (leak stop additive), do not connect the A/C service station and do not flush the refrigerant circuit.
Chemicals that seal leaks in the coolant circuit form deposits that affect the function of the A/C system and lead to failure of the A/C system and the A/C service station.
Inform the customer that there are substances in the A/C system that are not approved by Volkswagen/Audi and for this reason the A/C system cannot be flushed or serviced.
All Vehicles
Volkswagen/Audi does not approve the use of chemicals to seal leaks in the refrigerant circuit (leak stop additives).
Chemical materials to seal leaks in the refrigerant circuit react with air or the moisture in the air and form deposits in the refrigerant circuit (and the A/C Service Station) that lead to malfunctions in the valves and other components that come into contact with such chemicals. These deposits cannot be removed completely from the components, even by flushing. It is only possible to service the refrigerant circuit by replacing all the components that have come into contact with this material.
It is generally not possible to externally recognize chemical substances to seal leaks in the refrigerant circuit (leak stop additive), and the stickers that are supposed to come with them are usually not there. Therefore be careful when working with a vehicle if its service history is unknown.
If it is determined by the gas analysis that the refrigerant R1234yf is contaminated with another gas, it must be extracted from the refrigerant circuit and be disposed of as a gas from an unknown composition according to the legal requirements. Refer to VW / Audi ServiceNet and CONTAMINATED REFRIGERANT, FILLING IN RECYCLING CONTAINER FOR ANALYSIS, PROCESSING, OR DISPOSAL .
Due to contaminated refrigerant decomposition products can be created and accumulate in the refrigerant oil which cannot be extracted with the refrigerant. The contaminated refrigerant oil in this case is to be removed from the refrigerant circuit by flushing with refrigerant.
- The refrigerant circuit must be cleaned (flushed with refrigerant R1234yf) in order to force out moisture and other contaminants (for example abrasion from a faulty A/C compressor) as well as old refrigerant oil as efficiently as possible, without wasting refrigerant, without the need for extensive assembly work and without endangering the environment.
Clean the refrigerant circuit with refrigerant R1234yf (flush):
-- If dirt or other contaminants are in the circuit.
-- If the vacuum reading does not stay the same when evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in the refrigerant circuit).
-- The refrigerant circuit has been left open for longer than normal (for example, after a collision).
-- Pressure and temperature measurements in the circuit indicate that there is moisture in the refrigerant circuit.
-- If there is any uncertainty as to how much refrigerant oil is in the refrigerant circuit.
-- Under certain circumstances when contaminated refrigerant R1234yf is filled in the refrigerant circuit. Refer to COMPONENTS, REPLACING and REFRIGERANT GAS ANALYSIS, PERFORMING .
If contaminated refrigerant is determined inner damage to the refrigerant circuit components is indicated (for example corrosion on the inside of the refrigerant lines or loosened inside layer of the refrigerant hose) flushing the refrigerant circuit may not be enough. If this is the case all refrigerant circuit components must be replaced (a gas was filled which massively damaged the components).
-- A/C compressor had to be replaced due to internal damage (for example, noise or no output). Refer to COMPONENTS, REPLACING .
-- If it is stipulated by the vehicle-specific Service Information following the replacement of certain components.
Required Tools
- A/C Service Station with flushing device (for this A/C Service Station the auxiliary function "flush refrigerant circuit" and the refrigerant circuit flushing device required for it are present. Refer to the Parts Information.
- Passenger Vehicle Adapter Set Volkswagen/Audi. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT and the Parts Information.
There is also a Fill Hose with connections 5/8 -18 UNF and large inner diameter in short version (commercially available) included in the Adapter Set for Passenger Vehicles.