Sierra Synthetic Blend Mercruiser Sterndrive Engine Oil - Available in Quart to 5 Quart
Sierra Synthetic Blend Mercruiser Sterndrive Engine Oil - Available in Quart to 5 Quart
Sierra Synthetic Blend Mercruiser Sterndrive Engine Oil is a 25W-40 FC-W synthetic blend formulated specifically for Mercruiser sterndrive engines. It is NMMA FC-W Certified and meets API-SL requirements, giving boat owners a marine-rated lubricant built to handle the friction, heat, and load conditions that sterndrive engines see on the water. The synthetic blend base stock resists thermal breakdown under high RPM operation, extreme temperatures, and sustained loads, helping protect internal engine components from wear during long runs and hard use.
This oil delivers strong friction reduction and advanced lubrication to reduce wear on pistons, bearings, and other critical internal parts. Because sterndrive engines run at sustained high RPM and often under heavier load than automotive engines, using an oil formulated and certified for marine sterndrive service helps maintain proper lubrication and extend engine life. It is intended for use as directed in Mercruiser sterndrive engine oil change service.
This is a single product line offered in two package sizes to match routine oil changes or larger service jobs. Both sizes contain the same 25W-40 FC-W synthetic blend formulation.
Specifications
- Brand: Sierra
- Manufacturer Part Number: 18-9440
- Viscosity Grade: 25W-40
- Certification: NMMA FC-W Certified, API-SL
- Formulation: Synthetic blend
- Application: Mercruiser sterndrive engines
- Container Type: Bottle
- Mercruiser Cross-Reference: 92-883724K01 (Quart), 92-883725K01 (5 Quart)
- Available Sizes: Quart (946 ml), 5 Quart (4.7 L)
Sizes & Options
Choose the Quart size for a single oil change or for topping off between services. Choose the 5 Quart size to cover a full sterndrive oil change in one container without buying multiple bottles, or to keep a larger reserve on hand for routine maintenance.
Frequently Asked Questions
What sizes does this Sierra Mercruiser sterndrive engine oil come in? This Sierra Synthetic Blend Mercruiser Sterndrive Engine Oil (part number 18-9440) is available in a Quart (946 ml) bottle and a 5 Quart (4.7 L) container, so buyers can pick a single-quart top-off size or a larger container sized for a full oil change.
Is this oil certified for marine engine use? Yes, the 25W-40 formulation is NMMA FC-W Certified and meets API-SL requirements, both marks that confirm it is rated for marine sterndrive engine service rather than general automotive use.
What viscosity grade is Sierra part number 18-9440? It is a 25W-40 viscosity grade synthetic blend, formulated to hold up under the high RPM operation and heat load typical of Mercruiser sterndrive engines.
Which Mercruiser part numbers does this oil cross-reference? The Quart size cross-references Mercruiser number 92-883724K01, and the 5 Quart size cross-references Mercruiser number 92-883725K01.
Is this a fully synthetic oil? No, it is a synthetic blend rather than a full synthetic, combining synthetic base stock with conventional oil to resist thermal breakdown under extreme temperature and load conditions.
How much oil do I need for a full sterndrive oil change? For a complete oil change, the 5 Quart container of Sierra 18-9440 is sized to cover a full service in one package rather than requiring multiple individual quarts.
Does this oil protect against engine wear at high RPM? Yes, the synthetic blend formulation is designed to reduce friction and protect internal engine components from wear during high RPM operation, extreme temperatures, and sustained loads.
What container does this oil come in? Both the Quart and 5 Quart sizes of Sierra 18-9440 are packaged in bottles.
Is this oil intended for automotive engines or marine engines? This oil is formulated for Mercruiser sterndrive engines, a marine application, rather than general automotive engines.
How do I choose between the Quart and 5 Quart size? Pick the Quart size for topping off oil levels or a small partial change, and choose the 5 Quart size when performing a complete sterndrive oil change or when stocking up for routine maintenance.