I have a pair of crusaders with closed cooling system. Starboard engine is overheating. I believe the raw water system is ok because the risers and raw water hoses are cool when running the engine, intake confirmed good, impeller replaced less than a year ago.
That leaves the closed system. I flushed the system in the fall. I replaced the thermostat with new. I found some antifreeze gel under the pressure cap and in the overflow bottle, so I began to flush the system but all drained antifreeze was in good condition. I stopped the flush, topped up the coolant and started the engine. This time I removed one hose to be sure the pump was working and very little coolant poured through. I would assume that the pump needs replacement but could it be an air bubble? How can I rule that out? If I need to replace the pump can I just replace the impeller and gaskets? I have changed the raw water impeller, is this the same level of difficulty? Just looking for some guidance - thanks in advance.
That leaves the closed system. I flushed the system in the fall. I replaced the thermostat with new. I found some antifreeze gel under the pressure cap and in the overflow bottle, so I began to flush the system but all drained antifreeze was in good condition. I stopped the flush, topped up the coolant and started the engine. This time I removed one hose to be sure the pump was working and very little coolant poured through. I would assume that the pump needs replacement but could it be an air bubble? How can I rule that out? If I need to replace the pump can I just replace the impeller and gaskets? I have changed the raw water impeller, is this the same level of difficulty? Just looking for some guidance - thanks in advance.