Sierra Synthetic Blend 4-Stroke Marine Engine Oil, 25W40 FC-W, 1 Qt. – 9440CAT2
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Sierra Synthetic Blend 4-Stroke Marine Engine Oil – 25W40 FC-W | 1 Qt. | Part #9440CAT2
The same NMMA FC-W certified synthetic-blend 25W40 formulation as the larger jug and drum sizes, in a single-quart bottle. Designed specifically for 4-stroke inboard and sterndrive engines — including those with emission catalyst systems — this oil meets requirements that standard automotive engine oils cannot satisfy. Sold in case packs only.
Why FC-W Certification Matters
Marine 4-stroke engines run at sustained high RPM, face constant moisture exposure, and often sit idle for extended periods between uses. The NMMA FC-W standard is specifically designed for these conditions. Using an automotive oil in a marine engine can void the manufacturer’s warranty and accelerate internal corrosion and wear — FC-W certified oil is the correct choice for any 4-stroke inboard or sterndrive application.
Key Features
- NMMA FC-W® Certified / API-SL — meets the marine industry standard for 4-stroke water-cooled engines, with and without emission catalyst systems
- Catalyst-safe ZDDP technology — anti-wear additive package prevents phosphorus depletion and extends emission catalyst life
- Synthetic blend base — better thermal stability and oxidation resistance than conventional mineral oil
- SAE 25W40 viscosity — the correct grade for most 4-stroke inboard and sterndrive marine engines
- Enhanced detergents and dispersants — prevents sludge formation and keeps engine internals clean
- Corrosion inhibitors — protects internal components against moisture-related corrosion during operation and storage
- Wear protection and deposit control — maintains engine performance across the full service interval
- Prevents viscosity thinning — maintains oil film strength under high-performance conditions
Specifications
- Viscosity: SAE 25W40
- Certification: NMMA FC-W®
- API service: SL
- Application: 4-stroke inboard and sterndrive marine engines, with or without emission catalyst systems
- Size: 1 US quart (946 mL)
- Part number: 9440CAT2
- Sold as: Case packs only
Parts Desk Insights
Best use case: The single-quart bottle is the right format for top-ups between oil changes, topping off after a filter change, or keeping a spare quart aboard for longer passages. It’s also useful for engines with smaller oil capacities where a full 5-quart jug would leave significant leftover product. For a complete single-engine oil change, the Sierra Synthetic Blend 25W40 FC-W 4-Stroke Marine Engine Oil, 5 Qt. – 9440CAT4 is the more economical choice per litre. For high-volume shop use, the Sierra Synthetic Blend 25W40 FC-W 4-Stroke Marine Engine Oil, 55-Gallon Drum – 9440CAT7 delivers the same formulation at bulk pricing. To complete the service, pair with a compatible Sierra 4-Cycle Outboard Oil Filter.
Compatibility note: Always verify your engine manufacturer’s oil specification before use — viscosity grade, FC-W certification requirement, and API service category. Not all 4-stroke marine engines specify 25W40; confirm your engine’s requirement in the service manual. Sold in case packs — confirm case quantity at time of order.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.