Remove the impeller cap  from the bottom of the pump. Remove the screw that connects the impeller  to the shaft. Steel impellers have left-hand threads .
Carefully remove and clean the impeller . Check for wear or damage to the impeller .
Rotate the coolant pump shaft by hand. If the shaft does not turn freely, the motor bearings are damaged.
Install the impeller . Rotate the coolant pump shaft by hand, and make sure the impeller does not rub on the pump body . If the impeller rubs against the pump body, install shims between the impeller  and the coolant pump shaft. Install the impeller cap . If the impeller  rubs against the impeller cap , remove one shim at a time until it does not rub.
There are several filters that keep chips out of the coolant pump. Refer to Section 3 for filter maintenance information.