Liquids and oils
	The market for air conditioning maintenance and repair is booming. Behr Hella Service has almost all spare parts for the complete refrigerant circuit.

In the past, garages have had to stock up with different oils for servicing air conditioning systems. Thanks to PAOOil 68, our universal compressor oil, this is no longer necessary. The oil is supplied without (PAO-Oil 68 - Fig. 1) and with UV-dye added (PAO-Oil 68 Plus UV - Fig. 2).

Fig.1: PAOOil 68		Fig.2: PAOOil 68 Plus UV

PAO-Oil 68 is a high-quality multigrade synthetic oil which has been developed for universal application in all car and truck air conditioning systems, as well as for air conditioning systems installed in construction and agricultural machinery. The molecules in PAO-Oil 68 adhere to all metallic surfaces in the system, dispel other molecules and form a thin film on the surface of the system components. Since the molecules do not try to combine, this oil film is just one molecule "thick". This means that in contrast to many other oils, there is no danger of oil accumulation in the evaporator and a resulting reduction in cooling capacity when PAO Oil 68 is used.
Since the PAO-Oil only combines with the refrigerant to a minimum extent, only a small part of the oil (approx. 8 Vol %) circulates through the system. The rest remains where the oil is actually needed – in the compressor. Thanks to the highly active oil film in the components, the seal is improved and there is less friction between the moving parts in the compressor, thus reducing operating temperature and wear. This makes a major contribution to operational safety and reducing noises and ensures shorter running times and lower power consumption for the compressor.
PAO-Oil 68 does not corrode fluoric elastomer materials such as hoses or seals and is excellently suited for conversion from R12 to R134a refrigerant. Since PAO-Oil 68 is compatible with many other lubricants and refrigerants, it can be used both to refill oil quantities and replace the whole quantity of system oil.
Due to its independent molecular structure and density, PAO-Oil 68 mixes with other oils to a certain extent, but separates from them again when "at rest" (see Figs. 3 + 4) and thus does not form a solution in the same way as salt and water, for example. Thanks to its unique combination of highly refined synthetic hydrocarbon oil and special additives to increase performance, PAO-Oil 68 has a very large operating range (-68 °C to +315 °C).

Fig.3: PAG and PAOOil mixed		Fig.4: PAG and PAOOil separated

PAO-Oil 68 is not hygroscopic, i.e. it does not absorb humidity from the environmental air, again in contrast to other oils. Thus humidity problems such as components icing up or acids being produced can be counteracted simply by using PAO-Oil.
The application possibilities and storage ability of PAO-Oil 68 are significantly greater than with conventional oils. PAO-Oil 68 contributes to the improved performance of the air conditioning system and has been successfully used by many international air conditioning specialists for years.

PAO-Oil 68 Plus UV has the same positive properties as PAO-Oil 68. In addition, a concentrated and highly effective contrasting agent has been added, which is used for UV leak detection. The advantage of the low Vol. % concentration of the contrasting agent is that the complete properties of the oil are retained and it has no negative effects on system components or service units. 10 Vol. % of the system oil quantity are quite sufficient to achieve a sufficient troubleshooting effect. This corresponds to only 18 ml PAO-Oil Plus UV in the case of an overall system oil quantity of 180 ml, for example.
PAO-Oil 68 Plus UV can also be used as the only oil to fill the whole system, without this having any negative effect. PAO-Oil 68 Plus UV has been tested by the manufacturer and independent institues. Thus, for example, the chemical stability in connection with refrigerant and various O-ring materials was tested on the basis of the socalled "sealed tube test" in accordance with standard ASHRAE 97. All the tests returned a positive result, so that negative effects on components of vehicle air conditioning systems or air conditioner service stations can be excluded.
Thus PAO-Oil 68 Plus UV can be filled directly into a component, e.g. the compressor, or be added to the refrigerant circuit via the air conditioner service station.

To ensure that all application possibilities (refrigerant and compressor type) are covered, PAO-Oil 68 and PAO-Oil 68 Plus UV are available in the following versions: