PRI Magazine, August 2010 had an article about air filter intake systems. In the trends section was this comment: "The preference for oil-free filters continues to increase..... with the high incidence of oil-affected sensors, couple with the undersirable maintenance procedure involved with cleaning and oiling gauze products, low restriction, high efficiency, easy to maintain dry filters such as the R2C PowerFlow are gaining market share rapidly.
OK, so I expect the marketing spin by the gentlemen from R2C, but I was curious about the high incidence of oil-affected sensors. I've never heard this - has anyone?
Yeah, I've quit using K&Ns for this reason. If over-oiled, the oil can atomize and coat a MAF. To me, care and feeding of an oiled filter is a PITA and not worth the trouble.
Some cars have hard-to-get panel filters. Our Astra's air filter is $23 from Autozone and pretty similarly priced at the dealership. The K&N was $42. Add on a $10 oiling kit and I have much lower maintenance costs on that part. It's not all that hard to oil a filter.
Some people over-oil the filters. This can foul a hot wire air mass meter.
OTOH, you can oil the filter properly and enjoy 10+ years of filter life (like me.) The filter can be cleaned and re-oiled for max performance anytime I want. Also, CRC offers a AMM cleaning spray that works wonders on any kind of buildup.
Even properly oiled filters can kill a MAFS. The newer ones without the screens seem especially prone to failure.
I usually have an issue with the oil right after I re-oil my filters about twice. I simply unhook the intake tube and spray the Maf with cleaner and then I'm back on my way in minutes. The issue is WAY overstated.
The issue only seems to come about when I drive my vehicles too soon after oiling the filter. If I let it sit overnight before driving then i don't seem to have the issue.
carguy123 wrote:
The issue only seems to come about when I drive my vehicles too soon after oiling the filter. If I let it sit overnight before driving then i don't seem to have the issue.
I think that is the issue right there, most poeple are too impatient. Slow down, take your time and things should be fine.
having never played with the oiled filters.. knowing that you should let it sit before reusing is good to know
If K&N's recommended service intervals are followed, and the filter is washed, allowed to dry, oiled correctly, and allowed to dry again before use you won't have a problem. This assertion is based on having put K&N filters on every manner of car, motorcycle, scooter, race kart and Go-ped for decades.
I've used them long and hard enough to see if any trends involving top-end wear issues were to arise, and have see no evidence to suggest that assertions made that oiled-gauze filters don't "filter" well are unfounded.
FWIW, I usually wash with either Simple Green or diluted Dawn dish detergent in a pump bottle. Get the whole thing wet, immerse in a pail of warm water + detergent for 10 minutes then rinse from the inside out 'til the water runs totally clear.
Allow to dry completely. Spray w/ K&N oil lightly, allow to soak in and spread - you're looking for uniform light pink. Blot the any excess oil w/ paper towels. Dry overnight, before installation...
IIRC K&N says let the oil set overnight before installing the filter.
I typically install it and let it sit on the car overnight before cranking and driving and usually I have no troubles. The shorter the run from the filter to the intake the more likely I have been to have an issue, but as I said, a quickie spray in the intake usually clears up any issues and they don't arise again.
No problems from any of mine either. 30+ years of use. I clean them with diluted Dawn in a spray bottle, let sit in soapy water while I change the engine oil. Rinse with water til it runs clear. Let it dry over night then re-oil and let it sit at least over night wrapped in Scott blue shop towels to soak up any extra. I will install the paper filtre I removed to install the K&N if I need to drive the car.
IIRC, it was a big issue with Chevy trucks. I'm also pretty sure there was even a service bulletin about it. Supposedly the oil would throw off the MAF reading, and if not caught in time would mess the transmission up.
