Holes in K&N Filters..Hmmm..

[solaris=amazing]

Hey guys, would microscopic dust/dirt getting past the air filter..into the intake harm the engine to badly..? Wouldn't it be burnt up before it can do damage..?

I bring this question up because i was thinking of ordering a panel kn filter..which i did along time ago, had it in..then realized it had holes in it..and returned it. Now i got a fram filter in there, i did notice a slight drop in throttle response when i went from the kn to the fram paper one.

BTW, i work at autozone, and the other day i opened up 8 filter k&n filters boxes, including one cone type. Held them all up to the sunlight..HOLES.. No joke, tiny holes all over the place, small but still..HOLES.. These where brand new.

[solaris=amazing]

BTW, 3 months after i had my kn filter in my car, my maf sensor took a shit on me. There is another problem in itself, unless it wasn't the oil from the filter, and my maf just "went bad".

[Jet-Lee]

If filters didn't have holes, air couldn't get through.

Aren't you supposed to oil a K&N filter anyways?

[-Jayson-]

yeah the oil is supposed to collect the dirt. And normal air fitlers are rated at 99% cleanig efficiency, K&N are rated at 97%. So some air/dirt does get it.

[solaris=amazing]

I'm just thinking, should i spend the $35/40 after my discount to get the filter..? I did notice my car (95 4.6 tbird) was a bit more responsive with the kn, but i want to prolong my engine as long as possible.

[curtis73]

My MAF took a dump after the K&N as well. If you put too much oil on the gauze, it sucks it in past the MAF which destroys it. You can clean them, but they never seem to work right again.

The K&Ns use the oil to make dirt stick to it, and without the oil you can see a lot of light through them. They are very competent filters, but they do sacrifice a little bit of filtering for flow.

[MagicRat]

Even the K&N literature (from a few years ago) says the filtering efficiency goes up when the filter has a light film of dirt on it.

BTW I ran a Chevy 2.8 V6 in a Jeep with a K&N Filter since 1989. It needed a rebuild at about 120,000 km. It was so badly worn, I needed to bore it .080 over in order to get rid of the cylinder wear. I had maintained this engine very well, with frequent oil changes and filter maintenance.

I noticed the K&N had bigger holes than a new one after the mileage.

Since I also had a Chevy truck with a stock 2.8 L engine, stock paper filter and 415,000 km. It was running strong and had never had a rebuild. Therefore, I am suspicious of using a K&N, since it was the principle difference between these two engines.

[mysatilac]

In my opinion...
The differences here were that chevy didn't put there engine in a jeep (not right for the vehicle)... I drive a '97 saturn but I loved my old chevy, '86 corsica in perfect mechanical condition, the other difference was the driver's attitude (again in my opinon), Big Differences. and what year was the truck? You were the only driver of both? same size gears/tires/type of tranny?

But a K&N filter should not harm a vehicle mechanically except the MAF sensor as mentioned before, but that is really from over oiling (which is easy to do), your problem was somewhere else

[SaabJohan]

The peak efficiency of the filter is usually not when it's brand new.

In a K&N filter (and filters of the same type) the oil will take up all the small dirt particles, so it's important that the filter is in good condition. To clean and reoil the filter once a year is probably a good idea. Don't try to dry the filter with for example compressed air as it will destroy the filter.

A K&N filter has an efficiency around 97%, there are small differences between the tests that I have seen (tests according to SAE standards, not do it yourself tests with vacuum cleaners and coffee filters). There are paperfilters that are better than that, but there are also those that are worse. It alone will probably have no significant effect on engine wear, but running without/with a filter makes a large difference.

I have never noticed any problems with the MAF caused by filter oil, ok some MAFs breaks but this happens both with oiled and paper filters. Air mass meters are also often equipped with a self cleaning fuction heating the wire to 1000 degC (hot wire type meter). The wire itself is usually made of platinum so it's resistant to heat and oxidation. Note that some MAFs use a hot film instead of a wire which doesn't self clean. As for a MAF to get so dirty that if affects the function of it, you will probably have to use quite a lot of oil on your filter to get there, also remeber that oil from the crankcase ventilation can also find its was back to the MAF.