I think there is a lot of bad information when it comes to the use of K&N Air Filters - if anyone has taken the time to read the K&N website, they do a pretty good job of disproving claims that K&N Air Filters are detrimental to your car's health.
http://www.knfilters.com/MAF/massairfindings.htmhttp://www.knfilters.com/MAF/MAFTestresults.htmhttp://www.knfilters.com/MAF/massairpledge.htmI use a K&N Panel filter on my M2 and I am not worried.
I have also asked the question to K&N in the past and this is what they said:
Hello
Thank you for your enquiry. Please see details below from K&N web site.
Regards
27. Will a K&N filter cause my vehicle's mass air sensor to fail?
No, it is both impossible and ridiculous.
It is impossible because we know that the oil treatment on our cotton is very small (usually less than 2 ounces). Once the oil is properly and evenly absorbed through the cotton, no oil will come off, even under extreme engine conditions. It is ridiculous, because no dealership or service provider has ever been able to provide us with evidence to support this "myth," and in fact, our investigations have revealed that even authorized dealerships are simply speculating and do not have the test equipment necessary to know whether the sensor has failed or why. It is even more ridiculous because some car manufacturers use and sell air filters treated with oil on a regular basis. There are also major brands of disposable air filters that are treated with oil. We all use oil for the same reason, it helps in the filtration efficiency of an air filter. For more information on this topic including videos, see our Mass Air Flow Sensor Statement page.
Out of the millions of air filters we sell, we only receive a handful of consumer complaints each month that a dealership or service provider has blamed a vehicle sensor repair on our product. We take each complaint very seriously and see it as an opportunity to stop a consumer from being taken advantage of. We investigate the situation thoroughly and take full responsibility for resolving the issue. For more information on how we educate and persuade the service provider to reconsider their position, see Mass Air Flow Sensor Information & Testing. We are so confident in our ability to resolve these situations and to help a consumer fight back that we offer our Consumer Protection Pledge.
As a result of our standing up for consumer rights and providing assistance to resolve a disagreement, we have had over 100 actual sensors sent to us by dealerships who claimed our product had caused them to fail. Microscopic, electronic and chemical testing revealed that none of the sensors were contaminated by K&N oil (K&N Detailed MAF Sensor Test Results). What is perhaps the single biggest clue to what is going on is that over 50% of these sensors were not broken in the first place for any reason. Click here for more information on how this may happen.
