Several Parts shown in the attachment were found in the oil filter. BMW America was no help (Surprised?). My mechanic said the the repair would cost over $2000, but was probably not necessary.Is it necessary or not?
Thanks
What repair is the mechanic talking about? I don’t know the exact internals of your engine, but the loose parts apparently came out of the oil pump and got pumped into the oil filter. I would think the filter would have caught all of it, since the normal route is for the oil to go from the pump through the filter before distribution into the engine.
So it would seem like the only repair necessary is to replace the oil pump, which cannot be a $2000 job. (Or can it? I obviously don’t own a BMW). So what other repair is he referring to?
And if replacing an oil pump on a BMW is in fact a $2000 job, I once again am thankful for my Honda. 
What made you go poking around inside the oil filter? Or does this car use a cartridge type filter…Whatever, if this happens you get a new oil pump…They only thing to debate is who pays for it…Okay, that’s been determined so yeah, the anti drain-back valve is nice to have but not critical…
I looked at the lay out of that engine. The oil filter is a cartridge that is replaced through the oil pan/crankcase reinforcement. The oil pump seems to span to whole length of the crankshaft. It is driven by a chain in the front cover of the engine. The part is priced at ~$575 with labor time of 11.9 hours.
When the drain-back valve left the oil pump, it probably piled up on the filter element and then fell out when the filter cap and element were removed. How the valve is retained in the oil pump is not specified nor are the parts available separately from the oil pump.
The problem with having the oil drain back through the oil pump is that an air bubble might form above the filter cavity causing a delayed application of oil flow to the crankshaft and cam shaft bearings on restart. Possibly, the oil pump could lose its prime and not build pressure until the air cavity was cleared. Anyway, BMW thought it was necessary to manufacture and assemble the parts into this engine so obviously their engineering department knows something the average dealership mechanic does not.
How long after a start before the oil light goes out? If 5 seconds or less, I’d fugeddaboudit. (Remember, no revving until the oil light goes out.)