Ran into an odd one today '90 K75s

[Smithrjd]

Finally got everything back together after a full spline lube, went for a short ride to warm things up and op check. Time to change the fluids. No issues until I came to the oil filter.. My BMW filter socket did not fit.. Nor did any of the other three I have. BLEEP.. Used a double fold of some denim to finally get the filter loose. Blue filter, (dimples instead of flats) turns out it was an AC Delco filter?? (PF53) Last service was at a BMW dealer as well. (bike is new to me) The Mahle filter I replaced it with uses my standard oil filter socket, the one I have used on many BMW motorcycles.

[The Mighty Gryphon]

Yes, PF53 is the AC filter for bricks.  I used them for a couple years before it became easier to get a Carquest 85348 in my town.  I think the wrench I used on it was a 74/75 with 15 flats. 

[TriSpark]

This is your new best friend - https://www.amazon.com/Motivx-Tools-Adjustable-Filter-Removing/dp/B01BS5B3ZQ

I use that on my Brick and I run the PF53 oil filter with no issues. This style of wrench grips the filter, even when covered in oil, and spins it loose every time.

I would have expected the dealer to use the OEM filter, kind of surprised they didn't.

[The Mighty Gryphon]

AC filters are pretty good quality.  I'm pretty sure they are GM original equipment and I doubt GM would spec a filter that could jeopardize their warranties. 

They are pretty reasonably priced as well, as I recall.

[Chaos]

PF-53 has been my go to filter for decades but they are getting harder to find, big box stores don't seem to stock them anymore.  I too have multiple filter wrenches, sandpaper around the filter or if all else fails screw the wrench to the filter with a couple sheet metal screws. 

[stokester]

PF-53 has been my go to filter for decades but they are getting harder to find, big box stores don't seem to stock them anymore.  I too have multiple filter wrenches, sandpaper around the filter or if all else fails screw the wrench to the filter with a couple sheet metal screws.

Yes, the AC/DELCO filters are GM factory and dealership filters.
When I worked at the Chevy shop the new and newer vehicle used different filters from those used even five years ago so the stores will not be stocking them regularly.  I attributed this to the use of thinner viscosity oils, longer oil change duration and somewhat higher oil pressures used for chain tensioners and timing actuators.
I find the Bosch 72161WS from BeemerBoneyard works great for me.  Made in the US so it is probably the same as many others.