Here is a simple rule from our A/C professionals: always make sure you use the right type! If there is PAG oil in the system, recharge with PAG oil, if it’s POE oil, fill up with POE oil. Also, it is recommendable to use the special oils of the respective compressor manufacturer, because they are perfectly coordinated with the system.
To find out which type of oil is flowing through the cooling circuit, refer to the vehicle documents or the service sticker of the A/C system. When in doubt better always check and make a note of the viscosity!
PAG oils are fully synthetic, hygroscopic oils based on polyalkylene glycol. Vehicle and compressor manufacturers are using them in their factories in various viscosities – in A/C systems with R 134a or R 1234yf refrigerant.
PAO oils are fully synthetic, nonhygroscopic oils. That means that, unlike other oils, they do not absorb moisture from the ambient air. PAO oils are used for R 134a refrigerant, but they have no approval from compressor manufacturers.
Polyolester oils, abbreviated POE, are organic compounds and also belong to the category of fully synthetic oils. Compared to mineral oils, they excel with their high thermal stability. In terms of elastomer compatibility and hydrolysis resistance, they are inferior to mineral oils. POE oils are hygroscopic.
IDEMITSU is the world‘s leading manufacturer of polyalkylene glycol (PAG) oil, the primary lubricant used for automotive air conditioners. The Daphne Hermetic PAG offers superior performance, longevity and system compatibility. Ordinary, open-ended PAG molecules are quite chemically active. Typical PAG products are formulated by capping one end of the main carbon chain. The lubricants in the Daphne Hermetic PAG series, however, are formulated with both ends capped, making chemically inactive and very stable.