We all know that if you apply too much oil when reoiling a K&N air filter you might get oil migrating onto the fine wire in the MAF and screw up the MAF, requiring the MAF to be cleaned. Below are instructions for determining how much oil to put on your particular K&N air filter (filters vary in size, depending on the vehicle make, model, year, engine, etc., and they therefore vary in how much oil you should apply).

The K&N home page says the following for question 27 of the FAQ's:

"27. How much oil should I use to re-oil my filter after it is cleaned?
To determine the amount of oil needed for your filter, enter your filter's K&N part number in the Search by Part box on our Application Search Page. If you don't know the part number you can look it up on the same page. Be careful not to over oil your filter."

If you go to the K&N home page, which is: http://www.knfilters.com/ and find the part number for your vehicle's air filter, and click on the part number, you get a product specs page. That page will tell you how much oil to apply to the filter when reoiling. For example, below is the K&N home page site product specs page for the air filter for my 2003 3.0 liter V6 Ranger. Notice that under "Product Specifications" it states "Filter Re-Oiling Amount: 1.03 oz."

http://www.knfilters.com/search/prod...Prod=33-2106-1

Below is the K&N home page subpage for cleaning accessories:

http://www.knfilters.com/clningacc.htm

Note that for oil you can get either a 6.5 ounce spray can or a 12 ounce spray can or an 8 ounce squeeze bottle.

 

If you re-oil yours take some pictures and we'll make it into a How-To!

 

When you do it, be sure to let it sit for a little, the oils will spread out. I got a little overzelous the first time I reoiled it and had to redo it after using too much. I add some, let it soak, then keep adding until it is a uniform light pink throughout. Remember, you can always add more.

 

When I reoil mine I only apply the oil on the side of the filter that the air hits. That is, I do NOT also oil the side that faces the air intake tube and engine. I figure that the oil soaks into the fabric anyway, and if you oil the side that faces the air intake tube and engine it will be easier for oil to migrate onto the MAF if you overoil. I oil with a quick spraying, let it sit a few minutes, look for any parts that did not turn red, quickly spray those areas, if any, and then give it another quick spraying, covering the whole filter.

 

Actually, I think that the instructions that come with the K&N cleaning and oiling kit that you can buy are excellent and we don't need a How-To. The only things I can think of that the instructions do not cover is how much oil to apply to your particular filter and whether to apply it on the air intake side or the engine side or both sides. I'd be interested in peoples' opinions on which side to apply it too or whether you should apply it to both sides.

 

I also do not hit the inside. Figured the same as you, the oil on the outside catches the junk anyway.