Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A1 Sportback 2 ...
Air conditioner with refrigerant R134a - Edition 11.2018
Note
It is important to use leak detectors that are designed for the
composition of the respective refrigerant type. For example, a
leak detector for R12 refrigerant is not suitable for R134a refrig‐
erant because R134a has no chlorine atoms and the leak detector
therefore does not respond.
2.8
Refrigerant oil
Caution
♦ For information on how to handle refrigerant oil, refer to ⇒
Audi ServiceNet, HSO Environmental Protection (or ⇒
Volkswagen ServiceNet, Handbooks, Service Handbook;
Environmental Protection ) and observe local regulations.
Refrigerant oil mixes with the refrigerant (in a ratio of about
20 - 40 %, depending on compressor type and quantity of refrig‐
erant) and circulates constantly in the system, lubricating the
moving parts.
Special synthetic refrigerant oils, e.g. 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 air conditioner compres‐
sor. The use of non-approved oils can lead to the failure of the air
conditioning system, so it is important to use only the approved
types of oil.
⇒ Electronic parts catalogue
Type of oil for R134a in motor vehicles: PAG (polyalkylene-glycol)
Note
♦ Do not store refrigerant oil in open containers as it is extremely
hygroscopic (it attracts water).
♦ Always keep oil containers sealed.
♦ Do not re-use old refrigerant oil. Refrigerant oil must be dis‐
posed of as used oil of unknown origin (observe local regula‐
tions) ⇒ Audi ServiceNet, HSO Environmental Protection (or
⇒ Volkswagen ServiceNet, Handbooks, Service Handbook;
Environmental Protection ).
♦ Ester-based oils are currently only intended for use with large
systems (not for motor vehicle air conditioners).
⇒ “2.8.1 Properties of refrigerant oil”, page 13
2.8.1
Properties of refrigerant oil
The most important properties are a high degree of solubility with
refrigerant, good lubricity, absence of acid and minimal water
content. It is therefore only permissible to use certain oils. For a
list of approved refrigerant oils and capacities, refer to
⇒ page 333 .
PAG oils for refrigerant R134a are highly hygroscopic and do not
mix with other oils. Opened containers should therefore be closed
again immediately to prevent moisture from entering. Moisture
2. General information on air conditioning systems
13
English 
