Technical Reference

Compressor Oil Compatibility

A base-fluid miscibility guide for mineral, partial-synthetic, PAO, PAG, diester, silicone and POE compressor oils.

Miscibility is only one part of compatibility. Oils that blend physically may still differ in additives, viscosity, seal compatibility or performance. Confirm the exact products and compressor requirements before topping up, mixing or changing oils. This chart concerns oil-to-oil mixing; it does not establish refrigerant compatibility.

Compare two oil families

Existing oil familyReplacement oil family

M Generally miscible*N Generally not miscible*V Verify exact products

*Base-oil screening only. N assumes conventional oil-insoluble PAG; oil-soluble PAG products are an exception. Even M and same-family ratings require finished-product confirmation.

Base-fluid screening chart · M / N / V ratings explained below
Oil family	Mineral oil	Partial synthetic	Full synthetic (PAO)	Polyalkylene glycol (PAG)	Diester	Silicone	Polyol ester (POE)
Mineral oil	M	M	M	N	M	V	M
Partial synthetic	M	M	M	V	M	V	M
Full synthetic (PAO)	M	M	M	N	M	V	M
Polyalkylene glycol (PAG)	N	V	N	M	V	V	V
Diester	M	M	M	V	M	V	M
Silicone	V	V	V	V	V	M	V
Polyol ester (POE)	M	M	M	V	M	V	M

How to read the exceptions

Partial synthetic: Generally miscible with mineral oil, partial synthetic, PAO, diester and POE in this QA guide. A partial-synthetic designation does not identify a single chemistry; confirm the base oils and exact products. PAG and silicone combinations remain marked V.

PAG: Conventional PAG generally does not mix with mineral oil or PAO. Oil-soluble PAGs exist. The same-family M rating assumes matching PAG chemistry. Different PAG formulations can fail to mix with each other; confirm the exact products. PAG/ester combinations remain marked V.

Diester & POE: Both are ester families. M ratings apply the general ester-oil miscibility relationship to these families; they are not product-specific test results. PAG/ester mixtures require confirmation of the actual formulation.

Silicone: Methyl and phenyl silicone oils have different miscibility patterns. Silicone with silicone is marked M for matching silicone chemistry; combinations with other oil families remain marked V. Confirm the silicone type and exact products. Methyl silicone is generally not miscible with mineral, PAO, ester or conventional PAG oils.

Full synthetic: The PAO column specifically means polyalphaolefin. PAG, diester and POE can also be fully synthetic; the marketing term alone does not identify chemistry.

Plan the oil change

Provide the compressor model, both lubricant names, viscosity grades and operating conditions. Ask the lubricant supplier and equipment manufacturer for product-specific compatibility and changeover instructions, including any required draining, flushing and seal review.

Explore compressor oils → Ask QA about an oil change →

Sources & chart basis

QA screening chart based on Klüber Lubrication: base-oil miscibility table; the generic ester category is applied to diester and POE. Partial-synthetic and same-family M ratings reflect QA guidance and assume compatible base-fluid chemistry. V identifies combinations needing product-specific confirmation.

PAG limitations: Mobil Glygoyle 11, 22 and 30 product guidance. Oil-soluble PAG exception: STLE: New type of polyalkylene glycol, reporting Dow base-stock research. Chart updated October 10, 2026.