Check the impeller regularly and have a spare. Impellers are the heart of an engine s cooling system and require regular inspection and replacement under normal operating conditions. Running through silty or sandy water or running a pump dry can ruin an impeller quickly and cause the engine to overheat. It is important to monitor cooling water outflow and replace the impeller at the first signs of reduced outflow. Sierra replacement impellers are engineered to meet or exceed manufacturer s specifications to give boaters and technicians the confidence of an OEM fit and function. These neoprene impellers are compatible with many Yanmar 6LP-DT/ST and 6LPA-DT/ST diesel engines. Because unexpected failures can happen, it is important to have a spare onboard to save the day. Use our Engine Parts Selector or call 1-800-BOATING with your engine s serial number to confirm this is the correct impeller for your engine.