[mike944]

Well, you're running the right oil.....

apparently whoever "rebuilt" the engine didn't know what they were doing. Did they say why they changed the rods? That's a highly unusual part to change, unless you actually break one, and if you break one, there's usually enough secondary damage that the entire engine is junk.

Unless.......it did this same thing, about 16K miles ago, and whoever "rebuilt" it just put in new rods, and bearings without regrinding the crank. That will chew up a new bearing in a very short time.

That's why i mentioned regrinding the crank (or replacing it) It's definitely possible to just throw in some new bearings without grinding it, and slap it back together, but this same thing will happen again very soon.