Audi A4: Refrigerant Oil
General Information
Caution
When handling refrigerant oil, pay attention to local regulations.
Refrigerant oil mixes with the refrigerant (about 20-40%, depending on compressor type and amount of refrigerant) and circulates constantly in the system, lubricating the moving parts.
Special synthetic refrigerant oils, for example polyalkylene glycol (PAG) oil, are used in conjunction with R134a air conditioning systems. This is necessary as mineral oil, for example, does not mix with R134a. In addition, the materials of the R134a air conditioning system could be corroded as a result of mixture flowing through the refrigerant circuit under pressure at high temperatures or breakdown of the lubricating film in the compressor. Using non-approved oils can cause the HVAC system to malfunction. Only use approved oils.
Refer to the Parts Catalog.
Type of oil for R134a in motor vehicles: PAG. (Polyalkyleneglycol)
Note
- Do not store open containers of refrigerant oil because it attracts moisture.
- Always keep oil containers sealed.
- Do not use old refrigerant oil over again. For disposing refrigerant oil of unknown origin pay attention to local regulations.
- Ester-based oils are only intended for use in large systems at this time, not in passenger vehicle systems.
Refrigerant Oil Characteristics
The most important properties are a high degree of solubility with refrigerant, good lubricity, absence of acid and minimal water content. Only certain oils are permitted. For a list of approved refrigerant oils and capacities. Refer to → Chapter "Approved Refrigerant Oils and Capacities".
PAG oils, which are appropriate for refrigerant R134a, are highly hygroscopic and do not mix with other oils. Opened containers should therefore be closed again immediately to prevent ingress of moisture. Moisture and acids promote aging of refrigerant oil, causing it to become dark and viscous as well as corrosive towards metals.
Note
- Refrigerant oil, because of its chemical properties, must not be disposed of with engine oils or transmission oils. For disposing refrigerant oil of unknown origin pay attention to local regulations.
- Only the oil approved for the A/C compressor may be used in refrigerant circuits with refrigerant R134a. For the correct oil. Refer to the Parts Catalog. For the correct capacities. Refer to → Chapter "Approved Refrigerant Oils and Capacities".
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A/C System Operation
General Information
The temperature in the passenger compartment depends on the
amount of heat radiated through the windows and conducted by the
metal parts of the body. In hot weather it is possibl
General Safety Precautions
As per VBG 20, German industrial liability insurance
association.
Pay attention to the workshop-specific instructions. It
should be kept in the workshop.
Product Characteristics
Refrigerants use
A/C System and Refrigerant R134a Safety Precautions
Vehicles with a high-voltage system (hybrid vehicles)
Extremely Dangerous Due to High-Voltage
The high-voltage system is under high-voltage. Electrocution can
cause death or very serious personal inj
SEE MORE:
Hydraulic Pressure Sensor 1 -G545- and Hydraulic Pressure Sensor 2 -G546-,
Removing and Installing
Note
The Mechatronic remains installed.
WARNING
The system is under pressure.
The electronic ATF pump must be deactivated every
time before opening the transmission, and the hydraulic
pressure reservoir is drained.
Refer to
→ Chapter "ATF Pump, Deactivating and Draining
Rear Seat Backrest, Removing and Installing
Rear Seat Backrest, Removing and Installing, Fixed Rear Seat Backrest
Removing
- Remove the screws -1- in the
luggage compartment.
- Remove the bench seat. Refer to
→ Chapter "Bench Seat/Single Seat, Removing and Installing".
- Remove the bolts -1-.
- Remove the backres
