Impeller & O-Ring Kit | Sierra 18-8926

Sierra 18-8926 Water Pump Impeller & O-Ring Kit | Crusader RP061022 | Pleasurecraft Marine RP061022 | Mallory 9-45718

The Sierra #18-8926 is a water pump impeller and O-ring kit for Crusader and Pleasurecraft Marine (PCM) inboard engines and Mallory applications. Includes the impeller and housing O-ring(s) for a complete water pump service. Replaces Crusader RP061022, Pleasurecraft Marine RP061022, and Mallory 9-45718.

Part Details:

• Part Number: 18-8926 (Sierra)
• SKU: SIERRA-18-8926
• Manufacturer: Sierra
• Type: Water Pump Impeller & O-Ring Kit
• Kit Includes: Impeller and O-ring(s)
• Condition: New

Cross-Reference — Replaces:

• Crusader: RP061022
• Pleasurecraft Marine (PCM): RP061022
• Mallory: 9-45718

Additional Information

Crusader and Pleasurecraft Marine — Shared Part Number:

Crusader and Pleasurecraft Marine (PCM) share the same part number (RP061022) for this impeller kit, reflecting the common water pump design used across both engine lines. Crusader and PCM are both GM-block-based marine inboard engine manufacturers; their water pump designs share significant commonality. If you are looking up this kit from either a Crusader or PCM engine parts list, the Sierra 18-8926 is the correct aftermarket replacement.

Impeller and O-Ring Kit — Complete Water Pump Service:

The 18-8926 includes both the impeller and the pump housing O-ring(s), providing all components needed for a complete raw water pump impeller service on these engines. The O-ring seals the water pump housing cover or end plate; replacing it at every impeller service prevents leaks at the pump housing joint. Do not reuse the old O-ring — compressed O-rings that appear intact will leak after reassembly.

Water Pump Impeller Service Intervals:

Replace the raw water pump impeller annually or every 100 hours, whichever comes first. Neoprene impeller blades harden and crack over time, particularly in engines stored out of the water or unused for extended periods. A failed impeller causes loss of raw water flow and rapid engine overheating. Signs of impeller failure include engine overheating, reduced cooling water discharge from the exhaust, or impeller blade fragments found in the raw water strainer.

Inspect the Raw Water Circuit After Impeller Failure:

If the impeller has failed with broken blade fragments, flush and inspect the entire raw water side of the cooling system before reassembly. Blade fragments can lodge in the thermostat housing, heat exchanger passages, or exhaust manifold water jackets, blocking cooling flow even after the impeller is replaced. Remove all fragments before returning the engine to service.

Installation Notes:

• Confirm cross-reference part number matches your engine's existing impeller or water pump housing before ordering
• Lubricate impeller blades with dish soap or glycerin before installation — do not use petroleum-based lubricant
• Install impeller with blade curve in the correct rotational direction per service documentation
• Replace O-ring(s) included in the kit — do not reuse old O-rings
• Inspect pump housing bore for wear or scoring before reassembly
• Confirm cooling water flow after installation before returning engine to service

Frequently Asked Questions

1. What engines does the Sierra 18-8926 fit?
The 18-8926 fits Crusader and Pleasurecraft Marine (PCM) inboard engines that use part number RP061022, and Mallory applications using 9-45718. Confirm by cross-referencing the part number from your existing impeller or water pump housing documentation.

2. Why do Crusader and PCM share the same part number?
Crusader and Pleasurecraft Marine both build GM-block-based marine inboard engines and share common water pump designs. The shared RP061022 part number reflects the same impeller specification used across both engine lines.

3. Does this kit include the O-ring?
Yes — the 18-8926 includes the impeller and the pump housing O-ring(s). Replace the O-ring at every impeller service — do not reuse the old O-ring.

4. How often should I replace the impeller on my Crusader or PCM engine?
Annually or every 100 hours, whichever comes first. More frequently if the engine sits unused for extended periods — static storage causes neoprene blades to take a permanent set and lose flexibility.

5. What lubricant should I use to install the impeller?
Dish soap or glycerin. Do not use petroleum-based grease or lubricants, which degrade neoprene impeller blades over time.