I have had five different BMW six cylinder engines since 2003, and they keep changing the oil filter cap. As I recall, there was the one the oil filter strap wrench worked on, the one that needed the very large socket (36 mm) and the one that needed the special tool, like this.

Turner Motorsport - Item# 83300493936 / 83*30*0*493*936 - N52/N54 Oil Filter Tool - E60 E61 E83 E85 E86 E90 E91 E92 E93

For the large socket, I bought a special (36 mm) socket designed for wheel hubs on a Honda, and for the later one I bought a tool like the one in the link, but from a different supplier, just a local auto parts store.

Edit: as DKL pointed out below, it is a 36 mm socket and not a 32 mm socket as originally noted.

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2007 X3 3.0si, 6 MT, Premium, White

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