When switching to ExxonMobil marine lubricants, it is important to have a good understanding of the oils in use to ensure there will be no problems when potentially combining lubricants.
Five different circumstances related to switching and mixing lubricants are explained below. Please contact ExxonMobil for further advice and assistance if needed.
- Mixing two mineral oils
Mixing different mineral oils is generally low risk due to the similarity of the chemical hydrocarbon structure of all base oils. We still advise mixing our lubricant with the minimum amount of competitor oils.
- Mixing mineral oils with synthetic oils
Mixing synthetic oils with mineral oils is not recommended because doing so dilutes or suppresses the superior properties of synthetic oils. Some types of synthetic oils have different structures to mineral oils, leading to compatibility problems.
- Mixture of different synthetic oils
The risk of incompatibility between synthetic oils of the same base oil type is relatively low if they have the same basic chemical structure — such as polyalphaolefins or the same ester type. Synthetic oils of different base oil types should never be mixed, and we do not recommend mixing different brands of synthetic oils for the following reasons:
- Synthetic oils are generally used in high-performance equipment and are tailor-made for the specific application.
- Mixing two different oil brands may compromise lubricant performance.
- Used oil contains contaminants and impurities from the machinery operation that can cause instability when mixed with new oil.
- Mixture of different grease products
Different brands of grease generally combine well, as long as their soap components are compatible — such as two brands of grease each having a lithium base. However, if the soap base is not known, the grease should not be mixed.
- Mixing different marine engine lubricants
Base oils for marine engine oils usually have a chemically similar structure that typically does not lead to compatibility problems. It is always advisable to minimise mixing different oil brands, and ideally the products should be kept in segregated storage. However, it is recognized that this is not always possible.