Which oil is recommended?
Oil plays an important role in the air-conditioning system, no matter whether it's required when the compressor is replaced or for refilling during the air-conditioning service. Like blood in the human body, the oil fulfills vital tasks in the air-conditioning system. The use of high-grade compressor oil is therefore critical for the reliable and continuous operation of the system. The use of low-quality or even the wrong oil – just like with the engine – leads to increased wear, premature compressor failure, and loss of warranty/guarantee.
Also known as “Polyalkylene Glycol”, PAG oil is a fully synthetic hygroscopic oil designed specifically for automotive A/C compressors. It absorbs and binds humidity from the ambient air.
PAG1 (SP10) – Low Viscosity
PAG2 (SP20) – High Viscosity
“Polyol Ester or POE” is used when retro-fitting or restoring pre-1993 vehicles from R12 to R134 systems. Similar to PAG oil, it is also highly hygroscopic. Ester oil is also commonly used in R404a refrigeration systems.
R12 systems used mineral oils, but this oil will not dissolve in R134A refrigerant. Following the 1987 Montreal Protocol and development of more environmentally friendly refrigerant, R134A, a specialised synthetic lubricant is needed.
Universal oils are typically PAO-oils, or mineral oils with a different viscosity than synthetic PAG oils. This means that these oils do not mix well together, which can lead to poor lubrication, damages seals and increased wear.