Sierra Synthetic Blend 4-Stroke Marine Engine Oil, 25W40 FC-W, 55-Gallon Drum – 9440CAT7
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Sierra Synthetic Blend 4-Stroke Marine Engine Oil – 25W40 FC-W | 55-Gallon Drum | Part #9440CAT7
A synthetic-blend 25W40 marine engine oil formulated specifically for 4-stroke inboard and sterndrive engines, including those equipped with emission catalyst systems. The 55-gallon drum format is designed for marinas, marine service shops, and commercial operations that perform high volumes of engine oil services and want the cost and convenience advantages of bulk dispensing.
Formulated for Catalyst-Equipped Engines
The CAT designation in the part number indicates this oil is engineered to be safe for use with emission catalyst systems — a critical requirement for modern 4-stroke marine engines. The ZDDP anti-wear additive package is carefully balanced to deliver strong wear protection without depleting phosphorus in a way that damages catalytic converters, extending both engine and catalyst life.
Key Features
- NMMA FC-W® Certified / API-SL — meets the marine industry’s standard for 4-stroke engine oils and is approved for use in engines requiring FC-W certification
- Catalyst-safe formulation — ZDDP anti-wear technology protects against phosphorus depletion to extend emission catalyst life
- Synthetic blend base — better thermal stability and oxidation resistance than conventional mineral oil, at a lower cost than full synthetic
- SAE 25W40 viscosity — the correct grade for most 4-stroke inboard and sterndrive marine engines
- Enhanced detergents and dispersants — suspends contaminants and prevents sludge formation to keep engine internals clean
- Corrosion inhibitors — protects internal engine components against the corrosive effects of the marine environment
- Wear protection and deposit control — industry-leading additive package for extended engine life
- Prevents viscosity thinning — maintains oil film strength under extreme 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: 55 US gallons (208L)
- Part number: 9440CAT7
Parts Desk Insights
Best use case: The 55-gallon drum is the right format for marina service departments, marine dealerships, and commercial operations performing back-to-back 4-stroke inboard and sterndrive oil changes at volume. Bulk dispensing from a drum significantly reduces per-litre cost and eliminates the handling and disposal of individual containers. This is a high-throughput product — if you’re servicing a fleet of MerCruiser, Volvo Penta, or similar sterndrive-equipped boats on a regular schedule, the drum format pays for itself quickly. For smaller-volume needs or individual engine services, the Sierra Synthetic Blend 4-Stroke Marine Engine Oil, 25W40 FC-W, 5 Qt. – 9440CAT4 is the same formulation in a more manageable size. To complete the service, pair with a compatible Sierra 4-Cycle Outboard Oil Filter.
Compatibility note: Always verify your engine manufacturer’s oil specification — viscosity grade, FC-W certification requirement, and API service category — before use. Not all 4-stroke marine engines specify 25W40; confirm your engine’s requirement in the service manual.
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.