A mismatch can not only affect the reliability of your system but it can also destroy a system. These standards are intended to prevent cross-contamination of gases and oils, but these standards are not always followed through in boat refrigeration. All boat refrigeration systems should be labeled for type of oil and viciosity and the type of refrigerant used. Cruising boats must be extra careful in selecting a refrigerant as it might not be available in remote ports of call. Below is a list of the most commonly used oils in boat refrigeration.
Mineral is a wax free oil used for many years as a standard for refrigeration.
When it is mixed with Freon 12 it travels throughout the system, but it does not mix with R134a. Alkylbenzene refrigerant oil is a synthetic aromatic hydro-carbon. It is compatible with mineral oil and has improved oil return over mineral. It can be used with most refrigerants but NOT 134a. Almost all NEW low temperature AC hermetic compressors are serviced with Alkylbenzene oil.