PAG oil is a synthetic compressor lubricant used by original equipment manufacturers in their R134a automotive air-conditioner systems. PAG oil stands for polyalkylene glycol oil.
This type of synthetic lubricant is among the first developed for commercial and industrial use, and PAG oil comes in different viscosities for specialty applications. It has long been used by vehicle air-conditioning compressor manufacturers because of its outstanding lubricity and biodegradable properties. Recent developments have led to food-grade lubricants that are FDA approved for use with equipment that may accidentally come in contact with food. This new type of PAG oil is among the very few synthetic lubricants that have earned the FDA's seal of approval.