How to Choose Marine Diesel Engine Oil

They say that the two best days in a boat owner's life are the day they buy the boat and the day they sell it. While it is true that boat ownership and maintenance is often quite costly, you can avoid repairs with simple preventative maintenance and care. For boats with diesel engines, this is particularly true when dealing with engine oil and lubrication. Diesel marine engines are often used at very high loads for extended periods of time, requiring a special marine grade oil.

• 1

  Look for a marine diesel engine oil that is certified by the National Marine Manufacturers Association, or NMMA. The NMMA tests marine diesel engine oils to gauge their lubricating properties. NMMA-certified oils are recommended by manufacturers to prolong the life of marine diesel engines.

• 2

  Choose an oil that corresponds with the type of marine diesel engine that you are operating. NMMA-certified oils are available in three versions: TC-W3, FC-W and FC-W(CAT). According to the NMMA, TC-W3 is for use in two-stroke engines, FC-W is for four-stroke engines, and FC-W(CAT) is for four-stroke engines that have an exhaust treatment catalyst system.

• 3

  Choose either synthetic or partial synthetic oil. Synthetic oils are more expensive, but they may offer better protection for your engine. Partial synthetic oils are more affordable, but they may have reduced durability.

• 4

  Choose your oil's added characteristics. Sometimes, a specific type of oil is available for different purposes, e.g., high mileage or cold starting. Choose an oil that has the features that matter to you and your engine's characteristics.