Washable Air Filter?

Question

Does anyone have anything good or bad to say about washable air filters? I am considering buying a K&N Air Filter and the idea of being able to re-use the filter rather than dropping $15 each time is pretty compelling! I searched the google groups for answer but there is a lot of conflicting information, the KN web site of course offers glowing indorsements. Is it correct that I have to also buy a "cleaning" kit from the company to clean the little bugger?

Anyone have any experience with these filters?

Thanks!

Blake

Ray O · Accepted Answer

Washable air filters like K&N have several drawbacks. Most claim to improve air flow, and in order to achieve higher air flow in the same surface area, the pores have to be larger. If the pores are larger, they pass more dirt. More dirt will foul a MAF sensor more quickly and contaminate the oil and wear the engine more quickly.

Some "performance" air filters also use oil on the media to help trap dirt, and the oil can have a tendency to foul MAF sensors.

Unless you need the extra horsepower and are willing to sacrifice some engine life and MAF sensor life, I'd stick to a conventional air filter.

B A R R Y · Answer

How much is an oxygen sensor after it gets ruined by filter oil?

chasfs · Answer

The oxygen sensor is in the exhaust, so the air filter oil will not affect it at all. The mass air flow sensor is probably what you're thinking about. I'm not aware of any reports of the K&N damaging MAFs.

The K&N's are less restrictive than traditional air filter, and probably let some finer dirt particles through that a regular filter wouldn't. I guess the real question is how often do you change your air filter and how long do you plan to keep your car?

Good Luck!

-chasfs

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Dante · Answer

I've had a couple of K&N air filters and the only problems that I've ever had with them are MAF's getting dirty. You might want to pull them out and clean them every once in a while if you get a K&N.

My guess is that the fine particles that might get through the K&N are no worse than the fine metal particles that you get just from running your engine.

Dante

B A R R Y · Answer

TRUE!  My brain fart.

B A R R Y · Answer

Be aware that some current Toyota models have TWO air filters, the standard paper filter, and an internal, fine "cloth" filter.

The second filter is all the way inside the intake. I don't know how this filter would react if it got oiled.

C. E. White · Answer

Rather than continually repeat my thoughts on K&N Filter, I just saved them on a web page. See

Ray O · Answer

Excellent discussion! I have 2 points that you may wish to consider:

1) Bigger font for the first part of the page would be easier on my old eyes ;-) 2) In addition to the comparison between K&N and a Wal-Mart filter, it would be interesting to see the cost comparison between the K&N filter and a Motorcraft filter priced at MSRP. Although the OEM filter may cost more than the K&N, your point is still valid.

Washable Air Filter?

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