Water Pumps
About Water Pumps
The water pump keeps coolant moving through the engine and radiator. A small impeller on a shaft does the work, sealed where the shaft passes through the case. When the seal or bearing wears, coolant weeps out, the pump gets noisy, or circulation drops and the engine runs hot. On many engines a failed pump seal can also let coolant mix with the oil, which is serious.
Most listings are not whole pumps. They are rebuild kits with new seals and bearings, gasket kits, and impeller or water pump covers, each made for a particular engine, such as Honda, Yamaha, Kawasaki, Suzuki, KTM, Husqvarna and Gas Gas models. A rebuild kit restores the pump when the housing and impeller are sound. If the impeller or cover is damaged, a cover with an impeller is the part to look at, and some are made of magnesium or come in black. Always fit the correct gasket, and refill and bleed the system when you finish. Replace the coolant with the type your manual specifies.
Brands in this category include Athena, DEI, Hot Rods, ProX and Moose Offroad. Related categories are Gaskets, Seals & O-Rings, Pipes & Hoses and Radiators, all in Engine Cooling. Pick your machine in the Ride Finder at the top of the page for parts made for it.
FAQs on motorcycle water pumps
What does a failing water pump look and sound like?
Common signs are coolant dripping from the pump's weep hole or housing, a grinding or whining noise, overheating and coolant that disappears with no external leak. Milky or pale oil can mean the seal has failed and coolant is reaching the engine oil. Stop riding and have it checked.
What is in a water pump rebuild kit?
A rebuild kit normally contains the parts that wear, such as the seals and bearings, and sometimes a shaft. It restores the pump without replacing the housing. Read the listing for the contents, since they vary by model.
Do I need to drain the coolant to replace a water pump?
Yes. The pump is part of the coolant circuit, so drain the system to a level below the pump, and dispose of the old coolant responsibly. Refill with the coolant your manual specifies and bleed trapped air.
Should I replace the coolant when I fit a new water pump?
Yes, it is a good idea to refill with fresh coolant of the type specified in your manual, since the old coolant is drained anyway. If the old coolant is dirty or rusty, flush the system before you refill.
Is the water pump cover the same as the pump?
No. The cover, sometimes sold with an impeller, is the outer housing of the pump. A damaged cover or impeller is replaced as a part, while a worn seal or bearing is fixed with a rebuild kit. Check each listing for exactly what it contains.
