Water pump impeller blades scraping

[blue2000s]

Originally Posted by Frodo

That's kinda weird. The "little finger" part of the gasket---that should have been covered by the base of the water pump, right? If that's the case, how could it have bent out like that, scraping the blades?

Are you sure that finger didn't just stick to the pump when it was removed, bending outward at that point? Of course, if that's the case, it's hard to explain the grinding down of the impeller blades.

I thought of that but the aluminum surfaces that were exposed to coolant are a little darker than the surfaces that were dry. The surface that should be covered by the finger is dark. I think it was bent while assembled. There is no play in the bearing at all, so I don't know what else would have scraped the blades.

[JFP in PA]

The impeller is not scraping on anything, what you are seeing is tip erosion caused by cavitation forming at the vane tips at higher RPM’s, which is a normal event for these pumps.

[blue2000s]

Cavitation makes pits, not scratches.

[JFP in PA]

The bits breaking off during cavitation create the scratches as they drag across the vane tips...............

[blue2000s]

Originally Posted by JFP in PA

The bits breaking off during cavitation create the scratches as they drag across the vane tips...............

Maybe...

See how it is discolored where the tab would be. Is that something you typically see?

[JFP in PA]

No, not really, it says the gasket was not correctly in place. But I have seen the same type of vane erosion (and worse) on pumps where the metal gasket was were it belonged and could not have been a factor in the vane wear.

The only way to know for sure if the gasket was a factor is to remove it, lay it on the old pump, and see if the gasket "finger" can reach far enough to have casued the wear, and the gasket itself should be beat to Hell as well.

[Steve Tinker]

I agree with JFP - in fact, the gasket "finger" would have worn away completely if it was in rubbing contact with the impeller vanes - one very thin sliver of steel causing all that damage to six seperate vanes seems extraordinary.