Sierra 4-stroke 25W40 Engine Oil has been formulated to provide excellent lubrication and corrosion protection. Outboard engines operate under high load and running stresses. This product is developed for the marine environment and will outperform standard 4-cycle automotive engine oils. Sierra’s 25W40 oil offers excellent detergency, anti-oxidants, anti-wear, and corrosion protection. The benefits to your engine are: reduced wear to the internal components, protection of internal parts from corrosion, cleaner pistons, and prevention of ring sticking. Sierra’s 25W40 oil also provides excellent low temperatures properties. Sierra Quality Marine Lubricants exceed stringent Sierra and OEM warranty requirements.