Sierra 4-stroke 10W30 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 oil. Sierra’s 10W30 oil offers excellent, anti-oxidants, anti-components, protection of internal parts from corrosion, cleaner pistons, and prevention of ring sticking. Sierra’s 10W-30 oil also provides excellent low temperature operating properties. Sierra Quality Marine Lubricants exceed stringent Sierra and OEM warranty requirements.