Coolant Pump Impeller SIERRA 118-8921

Compatible Engines

Ensuring the reliable operation of your outboard motor requires using genuine or high-quality replacements like the SIERRA 118-8921 coolant pump impeller. This is a critical component of the cooling system, responsible for the proper flow of water through the cylinder head and engine block, preventing dangerous overheating during operation. This part is dedicated to TOHATSU engines with power ratings of 9.9-15-18 HP (2T) and 15-18 HP (4T).

Since the specificity of part matching can be complicated due to various production versions, compatibility should always be verified by the manufacturer's catalog number 118-8921 or the original OE number. If you have any doubts about selecting the right part for your specific engine model, we strongly recommend contacting our customer support. Our experts will help you confirm the correct selection, protecting you from incorrect purchases and potential installation issues.

Installation, Setup, and Operational Advice

Replacing the water pump impeller is one of the most important maintenance tasks a boat owner should perform. We recommend regular replacement of this component, even if it does not show visible damage, as worn blades can reduce cooling efficiency. Remember to thoroughly clean the pump chamber of sediment and limescale before removing the old impeller, as these can damage the new part. During installation, use only water from the cooling system as lubricant – never use lithium or silicone greases, which can dissolve the rubber and block the pump. Tightening the pump housing properly is essential for maintaining system integrity.

• High manufacturing precision – ideal dimensional fit (40.7x23.35x13.96 mm) ensures optimal fluid flow.
• Original material quality – durable rubber compound resistant to fresh and saltwater action.
• Essential for prevention – prevents failures resulting from TOHATSU engine overheating.
• Easy replacement – standard service procedure that extends the life of the power unit.