Sierra Lower Unit Seal Kit 18-2659, Replaces OMC 396355, for Evinrude/Johnson Outboard Gear Housings

The Sierra 18-2659 Lower Unit Seal Kit is a gear housing seal kit for Evinrude/Johnson (OMC) outboards, engineered to restore a watertight seal at the lower unit and prevent gearcase oil loss or water intrusion. It replaces OMC part number 396355 and is built as a complete kit so the impeller housing gasket and oil seal are replaced together during a lower unit service, rather than sourcing each component separately.

The kit contains two components matched to their original equipment specifications: an impeller housing gasket (Sierra 18-0969, O.E. 319586, qty. 1) that seals the water pump housing to the gearcase, and an oil seal (Sierra 18-2059, O.E. 321466, qty. 1) that keeps gear lubricant contained within the lower unit. Using the correct gasket and seal combination helps maintain proper water pump cooling and gearcase lubrication after a water pump impeller replacement or lower unit rebuild.

This kit is intended for technicians and boat owners performing routine lower unit maintenance or repair on applicable Evinrude/Johnson outboard gear housings, and is sold as a single part number, 18-2659, covering both included components.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2659
• Product Type: Lower Unit Seal Kit
• Replaces (OEM): 396355
• Weight: 0.21 pounds
• UPC: 030999312709
• Kit Contents - Impeller Housing Gasket: Sierra 18-0969, O.E. 319586, Qty. 1
• Kit Contents - Oil Seal: Sierra 18-2059, O.E. 321466, Qty. 1

Fitment

• Evinrude/Johnson (OMC) outboard gear housings originally fitted with OMC part number 396355

Replaces (OEM)

• 396355

Frequently Asked Questions

What does the Sierra 18-2659 Lower Unit Seal Kit replace? It replaces OMC part number 396355, so any gear housing originally using that OMC number can use Sierra 18-2659 instead.

What is included in the 18-2659 kit? Two components ship together: an impeller housing gasket (Sierra 18-0969, O.E. 319586) and an oil seal (Sierra 18-2059, O.E. 321466), one of each.

Is this a genuine Sierra part or an aftermarket copy? The 18-2659 kit is manufactured and sold under the Sierra brand, built to the original OMC 396355 specification rather than being a generic substitute.

How much does the seal kit weigh? The complete 18-2659 kit weighs 0.21 pounds.

Does this kit include a full gasket set or just the oil seal? It includes both an impeller housing gasket and an oil seal, not just a single seal, so both wear items are replaced in one kit.

What make of outboard is the 18-2659 kit designed for? This kit is designed for Evinrude/Johnson (OMC) outboard gear housings that use OMC part number 396355.

Can I use 18-2659 when replacing a water pump impeller? Yes, since the kit includes the impeller housing gasket (18-0969) along with the oil seal (18-2059), it covers the seal and gasket needs of a typical lower unit water pump service.

What is the UPC for this product? The Sierra 18-2659 Lower Unit Seal Kit has UPC 030999312709.

Are the individual components in this kit available separately? Within the 18-2659 kit, the impeller housing gasket is Sierra part 18-0969 and the oil seal is Sierra part 18-2059, each corresponding to its own O.E. Number (319586 and 321466 respectively).

Will 18-2659 fit a gear housing that lists O.E. Number 319586 or 321466? Yes, those are the O.E. Numbers for the two components inside the 18-2659 kit, the impeller housing gasket (319586) and the oil seal (321466).

How many oil seals and gaskets come in one kit? One kit of Sierra 18-2659 contains one impeller housing gasket and one oil seal, quantity one each.