Cummins QSB 480 – Raw Water Pump

[Kevin French]

Found that I am experiencing a raw water leak from the pump on my port Cummins QSB 480 engine (570-hrs). At low RPM there isn’t any leak however as I raise the RPM I can see the dripping from somewhere on the pump – I do see about a 1-2 gallons of water in my bilge following a 2-3 hour run and now realize it’s from this pump. I took off the black fan belt cover and noticed water hanging from the bottom of the pump housing. I need to dig a little more to find out exactly where it is coming from.

From anyone’s experience, is this something I can just tighten bolts to seal up the leak once I find it or is this something to call in a Cummins Tech?

Topic

[Tony Athens]

This is the factory Sherwood QSB pump and the water seal design have a dismal history of acceptable life.. Solution: It’s a new pump or a rebuild………… In the mean time, mitigate the saltwater damage to the engine mount, etc below the pump.. Damage is happening as I write. Below is what will happens if you do not address the issue.. UGLY!

Have you serviced your aftercoolers? Do you know what “Marine Age” is?

Tony

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