6. COOLING SYSTEM MXU 500 IRS Water Pump Body Remove the water pump body from the crankcase. Align INSTALLATION Apply engine oil to a new O-ring and install it onto the stepped portion of the water pump. Install the water pump into the crankcase while aligning the water pump shaft groove with oil pump shaft end. O-ring Align the mounting bolt holes in the water pump and crankcase and make sure the water pump is securely installed. Install a new O-ring into the groove in the water pump cover. O-ring 6-12