Regular impeller replacement keeps your outboards cooling system operating in top form—having a spare can save the day. Impellers are the heart of an engines cooling system and should be replaced annually. Sierra offers replacement impellers engineered to meet or exceed manufacturers specifications to provide boaters and technicians the confidence of a factory fit and function. Impellers can be quickly damaged if run through silty or sandy water or if the water supply is interrupted. Both situations can reduce water flow and cause the engine to overheat. We recommend taking along a spare for these unexpected failures. Key Features Impeller is engineered to meet OEM specifications Compatible with Nissan and Tohatsu outboards Application Guide Application18-8920 OEM Part Number18-8922 OEM Part NumberMallory9-45401—Nissan/Tohatsu Outboard3B2-65021-13C8-65021-2The Sierra Engine Parts SelectorIn addition to impellers, we offer a wide variety of other engine parts manufactured by Sierra. To see if we have the part you need, see ourEngine Parts Selector, where you can search by engine make, serial number and model or year of manufacture.