Over heating engine

[landonshaw]

I have been struggling with a Volvo Md2040d overheating. Finally purchased a new water pump">raw water pump. Prior to that, new thermostat, impeller, new antifreeze. Put the new pump on and went off on a day sail. Overheated again.

Got back and pulled all of the hoses and found four impeller fins. Used barnacle buster and flushed the engine with fresh water. I thought the fins were from yers of not finfpding them since the new pump had a new impeller.

Went out for a sea trial, overheated. Figured I would start from the impeller and proceed back to the heat exchanger. Pulled the plate off the pump and found four fins missing with a fifth ready to break.

Replaced the new impeller it’s. Newer one and problem solved. I imagine that the impeller on the pump was placed in the pump a long time ago and has been sitting on a shelf drying out.

Just some thoughts on new parts with rubber that can get dry over time.