Oil Filter Leak Question

[BSTWAY]

I’ve got about 48k on the bike and will be performing service soon. Yesterday I noticed a drop of oil on the bottom of the oil filter. I know for a fact that it hasn’t leaked in almost 6k miles. What would cause this to happen all of a sudden? I was thinking it has been slowly backing off over time or maybe just the seal has gone bad.

[TicTac50]

I know for a fact that it hasn’t leaked in almost 6k miles.

6K miles looks like it is time to change the oil and filter anyway.
I would change oil and clean oil filter housing really good, before installing new filter.
I always fill up the filter with oil and apply some of it to the seal.
Make sure you apply correct torque (11Nm) when installing oil filter. Keep an eye on it for a while.
I don't think it will leak again.
Good luck.

[Boxer]

The last time it was changed, the rubber filter seal may have been stuck and left in as the new filter was screwed in place on top of it. That happens. When you change it out, make sure there is not an old rubber seal ring stuck up in there.

[Sunbeemer]

If it's a BMW filter, the rubber gaskets are very soft and seal well using the correct amount of torque, but overtightening will split them resulting in a leak (DAMHIK)

[snowprick]

When you have removed the filter and cleaned the area, use a strong flashlight and mirror to look at the seal contact area. Dont be shy with the mirror, you are not doing dentistry. Use a good mirror about six inches diameter or better (your wife will have one) and use a strong flashlight. Big re-chargables are usually the best. Its amazing what you can find with simple tools.

[iowabeakster]

To go along with snowprick's idea...

Take a shop towel and clean that contact area to make sure the seal has a clean surface to press against.

Be careful when reinstalling the new filter. As you are raising the filter, be careful not to bump it against the wall that surrounds the filter. If you knock dirt/dust onto the seal it might not seal completely, or worse knock dirt inside the filter and get pumped directly to vital engine parts.

It's too bad BMW did not see to putting a cover over the filter recess to keep excess dirt out of that area. But I suppose they would make an expensive propreitary wrench to remove the cover.

[OU812]

The K "Flying Brick" engines have such a cover using 3 allen bolts. I use K&N filters as no special BMW wrench needed.