Oil Filter

[fig]

Can anyone vouch for K&N's kn-161 oil filters? Just bought one on Amazon for only $2.14, but now I'm having second thoughts about using it. Mostly because of one bad review which mentions how the filter had "completely collapsed". Any thoughts?

https://www.amazon.com/gp/product/B000F ... merReviews

R75/5

[Kurt in S.A.]

I recently read some posts on the Airheads listserve (posts were probably 2-3 years old) that were not complementary of the K&N filters. The discussion was around collapsed filters of which K&N was part of the problem. OEM filters, those by Mahle, have an internal pipe which helps support the filter element to avoid that situation. The bendy filter actually improves the stiffness of the filter element over the long filter...I actually prefer the bendy filter for my /7. I will never use anything but OEM in my bike. Oil and filtration is just to important.

Kurt in S.A.

[Zombie Master]

I have read for years that K&N air filters flow better but do not filter the air as well as OEM. So I would not be using their oil filter.

[fig]

Yeah I've always bought OEM but $2.14 delivered.. I couldn't resist! Anyway, just went back and purchased a Mahle split filter from Amazon for $17.28. Definitely pricey but piece of mind is worth something I guess. Thanks for the input

[Wobbly]

Several thoughts on BMW oil filters...

• Oil filters should be judged by the level of filtration they offer. Look for definitive information on their rated micron size rather than simply going by rumors or assumptions.
• Since oil enters the BMW Airhead filter from the outside and passes into the center, it is important to look for structural elements (such as the perforated metal support) that keep the filter from collapsing.
• Oil filter collapse is most likely to happen when motor oil is cold and thick. Owners can help prevent this by the way they ride the first several miles after initial morning startup.
• Due to the engine making less debris, once an engine hits ~25,000 miles it becomes less important to change the filter with every oil change.
• Mahle and Purolator are the 2 official BMW filter suppliers. Purolator filters can be purchased in the USA through many different sources. A Purolator filter probably doesn't need to arrive in an expensive BMW box to be as effective.
• Although nearly identical, oil filters for Airheads differ between those bikes with and without oil cooler. Since most web advertisements show only a single photo from one angle, it becomes dangerous to buy even name brand filters without details. Oil cooler filters do not have the central rubber seal on one end and must be installed in a special direction. Pre-oil cooler filters can be fitted either direction. IMHO, the bendy, two-section filter construction is not a reliable indicator.

Hope this helps.

[barryh]

Well a K&N wouldn't be my choice but Airhead Oil filters have been collapsing occasionally for almost 40 years and the first documented ones were BMW OEM fitted by BMW service centres. Unless there is a complete absence of a perforated metal tube I'd doubt the K&N is worse than many others. In any case the metal tube doesn't necessarily prevent it although the gauge of the tube metal might vary. Assuming it looks structurally sound I'd be concerned if the overall length across the end seals is too long as it's my belief that excessive end compression on installation pre-disposes them to collapse by kinking the pleats. If you are going to use it I would trial fit the filter without the $2000 O ring in place to see how much pressure is going to be needed to compress the end seals. I've had to shorten end seals to make the filter fit.

[Kurt in S.A.]

This the reason that the bendy filters help with preventing collapse. The unsupported length is reduced while the amount of filtration area is still more than enough to provide filtering of the oil.

Kurt in S.A.

[fig]

Just double checking.. Which models get the $2000 O-ring? I have a /5 and have never used one.

[Rob]

Just double checking.. Which models get the $2000 O-ring? I have a /5 and have never used one.

/5 is exempt.

You have the internal cover with the central fastener.

[Kurt in S.A.]

/6 is exempt also...for the record.

Kurt in S.A.