Hey guys,

I am overhauling my 6 bolt and was hoping to reuse my OEM oil pump as it is relatively low mileage, has straight cut gears, and everything looks great aside of this weird casting. Is this normal? It almost looks like cavitation wear to me, but I am probably just over thinking this.

Any input is appreciated!

I'm no expert on these parts, but that simply looks like the machined surface preserved by ample oil lubrication. If it were wear, I would expect all the little lines to be in concentric circles, like a brake rotor. An end-milling cutter head would leave those kind of x-pattern swirls. How did the pump gears look on their sides?

Im sure its fine, its also just the half machined, half rough circle that made me question it. Gears and everything looks great, no wear on teeth, bearing surface, anything. I think its likely fine as well, but just wanting to double check.

Mine didn’t look like that so idk if it’s “normal”. Check the clearance.

Are you 100% sure it's OEM? The surface finishing doesn't look like Mitsubishi's. If it's OEM but if you didn't buy the pump as new by yourself, maybe the previous owner machined to smoothen the surface. Anyways whatever manufacturer, you should check all clearance before you assemble.

You might find this somewhat interesting/helpful:

measurements came out fine, and no signs of any wear on the gears or pump itself. I assume its just a casting flaw that is below the machined surface. I have never had any oiling issues with this motor, no contamination issues or anything, and the pump is less than 20k old, so I think risk is low.

Thanks for the input and link to the video, all helpful discussions.