Sierra 18-7921 Oil Filter, Replaces Mercury 35-877767K01, Fits 135-200 HP Verado L4 Outboards

The Sierra 18-7921 is a spin-on oil filter engineered for Mercury Verado L4 outboards, providing high-efficiency filtration to protect the engine's oil system during operation. Built with a heavy-wall steel canister and epoxy coating, the filter resists corrosion in the marine environment while standing up to the pressures of regular engine cycling. An integrated anti-drain-back valve keeps oil in the filter between starts, reducing dry-start wear and helping maintain steady oil pressure at ignition.

Filter media is manufactured to meet or exceed OE filtration standards, capturing contaminants that would otherwise circulate through the engine and accelerate wear on bearings and moving parts. The filter uses a 24mm x 1.5 thread spec and is designed as a direct fit for Mercury Verado L4 outboards across the 135, 150, 175, and 200 HP range. It replaces Mercury part number 35-877767K01, making it a straightforward drop-in replacement during scheduled oil changes or maintenance service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7921
• Product Type: Oil Filter
• Thread Spec: 24mm x 1.5
• Material: Steel
• Item Dimensions: 4 x 3.25 x 3.25 inches
• Weight: 0.75 pounds
• Features: Anti-drain-back valve, epoxy coated, high-efficiency filter media

Fitment

• Mercury Verado L4 135 HP, 2006-2011
• Mercury Verado L4 150 HP, 2006-2011
• Mercury Verado L4 175 HP, 2006-2011
• Mercury Verado L4 200 HP, 2007-2011

Replaces (OEM)

• Mercury 35-877767K01

Frequently Asked Questions

What engines does the Sierra 18-7921 oil filter fit? The Sierra 18-7921 fits Mercury Verado L4 outboards in the 135, 150, and 175 HP range for 2006-2011, and the 200 HP Verado L4 for 2007-2011.

What OEM part number does the 18-7921 replace? It replaces Mercury part number 35-877767K01, making the Sierra 18-7921 a direct equivalent for Verado L4 outboard oil changes.

What is the thread size on this oil filter? The Sierra 18-7921 uses a 24mm x 1.5 thread spec, matching the fitting on Mercury Verado L4 outboards.

What material is the filter canister made from? Steel construction with an epoxy coating gives the 18-7921 canister added corrosion resistance for marine use.

Does this filter have an anti-drain-back valve? Yes, the 18-7921 includes an anti-drain-back valve that keeps oil in the filter between engine starts, reducing dry-start wear.

How much does the Sierra 18-7921 oil filter weigh? It weighs 0.75 pounds.

What are the dimensions of the 18-7921 filter? The filter measures 4 x 3.25 x 3.25 inches.

Is the Sierra 18-7921 genuine Sierra or aftermarket? The 18-7921 is a genuine Sierra-manufactured part, built as a direct replacement for the Mercury OEM filter rather than a generic aftermarket copy.

Does the filtration meet OE standards? The 18-7921 uses high-efficiency filter media that meets or exceeds OE filtration performance for Mercury Verado L4 outboards.

Will the 18-7921 fit a Verado L6 outboard? No, the 18-7921 is designed for Verado L4 models; Verado L6 outboards use a different Sierra filter part number.