What is the most suitable Oil for an Inboard Marine Engine?

Generally, doubts arise about which oil is the most appropriate for a marine engine, and that is why one of the most frequent queries to Solé's technical service is precisely to know what oil to put in a boat engine and marine transmissions.

If you want to know what type of oil is in your boat's engine and how you can extend the useful life of your propulsion and generation equipment, below you will find advice that will help you with regular maintenance.

What is the most suitable Oil for an Inboard Marine Engine?

Multigrade Oil for Marine Engines and Generator Sets

For Marine Engines, Marine Generator Sets and Hydraulic Inverters, we always recommend using a multigrade oil specially designed for these types of machines. Solé 15W40 Multigrade oil, certified ‘ACEA E5 / E3. API CH-4 / SJ", is specifically formulated to lubricate the engine in harsh conditions, withstanding high loads and high temperatures. This oil not only provides excellent lubrication, but also acts as a corrosion protector, keeping the inside of the engine clean and reducing wear, resulting in increased durability.

Mechanical Gearboxes Oil

For Mechanical Gearboxes, we recommend always using ATF Oil. Solé ATF oil is formulated to reduce friction and friction that normally occurs in mechanical transmissions. Thanks to its special components and additives, this oil offers a great anti-wear power and allows an impeccable power transmission from the engine to the propulsion line. Using this oil in your mechanical inverter will optimise its performance and extend its service life.

Importance of following the manufacturer's instructions

It is essential to always follow the instructions we provide as the manufacturer, as the engine manual contains instructions on the ideal type of oil and the recommended maintenance intervals.
Using the correct oil and performing maintenance at the correct intervals ensures that the engine performs optimally, preventing failures and prolonging its service life. Failure to follow these guidelines can result in sub-optimal engine performance and possible unforeseen events in the future.

Use of Solé Genuine Oils and Fluids

We recommend using Solé original oils and fluids because they have been specifically formulated to provide the best performance in our machines. These products are designed to meet the exact technical specifications of our engines and transmissions, ensuring perfect compatibility.

Using genuine Solé products ensures that your engine and transmissions are properly protected and cared for, minimising the risk of damage and breakdown, and maintaining the optimum performance of your equipment.

Importance of good lubrication

Good lubrication is essential for the efficient operation and longevity of the engine or generator. Proper engine lubrication not only reduces wear and friction between moving parts, but also helps to keep the engine clean and prevent corrosion. It is important to regularly monitor the condition of the oil and make the necessary changes according to the manufacturer's recommendations. This ensures that the engine is always protected and running efficiently.


Remember that good lubrication is key to obtaining the best performance and extending the life of the engine or generator. Always consult the owner's manual before carrying out any maintenance and trust only authorized Solé professionals.
This will not only ensure that the correct procedures and products are used but will also give you peace of mind knowing that your equipment is in the best hands.

What is the most suitable Oil for an Inboard Marine Engine?