I think I can add a little value to the conversation on this concern. In our 4.8is applications the filter is located on the bottom back of the engine, not top side like 80% of all the other BMW models due to the block changes. The anti drain-back valve is designed to keep oil in the filter housing when it is not pressurized (ENGINE OFF). In the top side mounted filters this is a large issue as the engine would experience 8-18 seconds of ZERO oil pressure on start up as the oil would have to travel up the line from the engine, fill the filter area, then down to the pump to be transferred through the main bearings, etc.

On the 4.8is the filter hangs on the back side of the oil pump housing near the oil pan. The filter housing is never empty of oil after the engine is started as it hangs upside down. The quick way to determine if the valve is functioning is to open up the drain valve on the filter housing (The little one) and see how much oil comes out.

Part #2 is the plastic basket that holds the filter element upright so oil will filter normally through it. Without it the filters will collapse.

I do not believe we have a "by-pass" valve incorporated into our pump/filter housings. Has anyone on the forum ever cut one apart?

I also think the parts guy is a little confused on which part you need and the labor involved. There are two parts of the pump/filter assembly. You only need to exposed parts of the filter housing. NOT the entire pump assembly to replace the valve. See images below:

Attached Images

  

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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green