Air filter ?

Have a 2005 Legacy 2.5GT Wagon, just bought, and want to replace air filter.

Have read that the oiled filters, K&N, etc. will cause problems with the electronic sensors. Is that so? If not recommend filter, if is so recommended filter.

 

Bob

Oh boy - there was another thread recently I had started about this because I was curious about the same thing. Had a K&N air filter in my hand, and returned it without installation because these guys all scared me. I'm just running stock because even the dry filters will only give you 1-2 more horsepower, but still you're increasing air flow, which is theoretically allowing more particulates to pass through the element.

I've been running an oiled filter (Perrin) for nearly 20k miles now with no issues.

AVO......ftw

I have a K&N on my 06. Been running it about a year now. A little louder than I would like but no Problems!

I think the problem stemming from oiled filters is OVER-OILING the filter. I have only had a K&N filter in this car for 5 or 10 thousand miles. I have had a K&N filter in other cars though, and I've never had any sensor or engine problems.

 

If you are worried about it, just buy a replacement paper air filter. Like someone already said, on a car with basic power mods, you don't gain much power anyway with any type of panel filter. Plus, you'd have piece of mind. That's worth 1 or 2 horsepower, easy.

AVO panel filter

The filtration tests that were done here a while back on hi flow filters verses OEM types opened my eyes to the amount of dirt hi flow filters can allow into your engine

 

http://www.bobistheoilguy.com/airfilter/airtest1.htm

 

Then click on "Air Filter Filtration Testing"

 

Check it out if you haven't seen it already.

I think the problem stemming from oiled filters is OVER-OILING the filter. I have only had a K&N filter in this car for 5 or 10 thousand miles. I have had a K&N filter in other cars though, and I've never had any sensor or engine problems.

 

If you are worried about it, just buy a replacement paper air filter. Like someone already said, on a car with basic power mods, you don't gain much power anyway with any type of panel filter. Plus, you'd have piece of mind. That's worth 1 or 2 horsepower, easy.

 

Well said, its over oiling. When I renew the oil on my K&N filters I hang the filter up over nite and let it dry and put it back in the car in the morning. MAF's are just too expensive to replace.

K&N style filters do allow more dirt to pass. That's why I only use a K&N on my 2004 Mach1 which is lowered and NEVER sees gravel or dirt roads.

 

I use OEM filters on both my Legacy GT and 2005 Powerstroke Diesel. The Powerstroke comes factory equipped with a Donldson filter that has proven to be a superior media (they make filters for M1 Abrams tanks) that can hold up to 3.5 lbs. dirt and yet there are plenty of bozos who replace them with K&N style filters. Then, they take their trucks off road and, drum roll please .... "dust" their engines. The dirt ruins the turbo charger and more and Ford voids the warranty.

 

If your Legacy sees dirt or gravel roads, I'd stick with a regular filter. If you insist on a K&N, Buy two.

 

They come pre-oiled, so when the first one gets dirty dirty drop in the second new filter. Then, clean the dirty one and apply oil SPARINGLY. Spray on a light coat of oil. If there are bare spots, don't worry as oil will migrate through the filter. Put the filter in a plastic bag and store it on its end.

 

Months later, when you need a clean filter, the excess oil in the wrapped one will have dripped off the foam. This is the best way to avoid getting excess oil sucked onto the MAF.