What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

K&N air filter oil

Radioflyer

Well Known Member
I will soon need to inspect and clean my K&N filter. I know they are routinely re-coated with their special oil. Does anyone know what's so special about this Oil? Might it just be a very lightweight mineral oil with red dye? Has anyone tried their own...such as marvel mystery oil, or pharmaceutical mineral oil diluted with mineral spirits,,or ....?
 
I have the official K&N cleaning and oiling kit, and the oil does not seem to be anything special, and in fact, it's not even red. And it's not sticky.

I recall the red oil was a bit sticky, but the last time I used it was in the late 1970s so take that with a grain of salt.

The oil on the new filters was red and sticky - I've been too lazy to clean them so have been buying new ones, but I figured after 3 it's time to start cleaning them. The process to clean was no problem, I used a pail in the bathtub with the special cleaning liquid, which is probably just dish soap. Lots of rinsing from clean side to dirty side, and then a couple days of air drying.

The main thing I found in the filter was not dust or dirt, but insects.

Unless you are taxiing around in a very dusty environment, I think just about any thin oil is going to be fine in this filter. You'd probably be fine with no oil.
 
Just cleaned and oiled mine with the K&N kit. It’s RED and STICKY. U really want to try and save $3 and use something else. OK.
 

The K&N air filter keeps the insects out, at least.

My experience with K&N air filters on motocross bikes many years ago was horrible - engines that literally had sand sitting inside the carb. Since I worked in a machine shop rebuilding motocross engines, I loved K&N filters - they brought us a lot of business!

One challenge with paper filters like you saw in that test is - how do they handle rain?
 
Just cleaned and oiled mine with the K&N kit. It’s RED and STICKY. U really want to try and save $3 and use something else. OK.

It's not about the money. It's more about not brainlessly following dictum and trying to understand the mechanism or functionality. I like to de-mystify.
 
The K&N air filter keeps the insects out, at least.

My experience with K&N air filters on motocross bikes many years ago was horrible - engines that literally had sand sitting inside the carb. Since I worked in a machine shop rebuilding motocross engines, I loved K&N filters - they brought us a lot of business!

One challenge with paper filters like you saw in that test is - how do they handle rain?

Based on the drain hole for rain, Van's doesn't expect much volume. Only the face of the filter is going to get damp......only if you fly in rain.

It's very simple, air partly filtered for a little more MP. I do have a K&N in my RV. but I will be trying out a Wix that I found that will (should) replace the K&N. Purchase locally cheap, and toss it when it gets dirty..... just like my truck.
 
They put solvents in the oil to help it absorb into the cotton. These later evaporate and the oil is then thicker. Guessing the EU has more stringent VOC limits than the US.

Makes sense to me. I'm looking forward to that .0001" of MP boost with the thinner oil! :D
 
Makes sense to me. I'm looking forward to that .0001" of MP boost with the thinner oil! :D

The K&N recharge kit we sell does indeed have a red color to the oil and after applied turns quite sticky.
Because of the way the K&N filter functions, I would not use one on my airplane without the proper (sticky) oil.
 
The K&N air filter keeps the insects out, at least.

My experience with K&N air filters on motocross bikes many years ago was horrible - engines that literally had sand sitting inside the carb. Since I worked in a machine shop rebuilding motocross engines, I loved K&N filters - they brought us a lot of business!

One challenge with paper filters like you saw in that test is - how do they handle rain?

My experience on motorcycles, too. And a totalled BMW R1200RT due to the filter media coming loose while the engine was running.

Racetracks that won't allow bikes with K&N filters on them because they have a reputation for spilling oil.

I'm not going there.
 
If not K&N

Sounds like some won’t use K&N for various reasons. If not K&N, then what will be used for an air filter? Easy to say won’t be used, but alternative approaches are not being presented. What’s the plan to keep the air flowing into the engine clean? For example, on an O-320 with carb.
Thanks.
 
K&N air filter alternative

Sounds like some won’t use K&N for various reasons. If not K&N, then what will be used for an air filter? Easy to say won’t be used, but alternative approaches are not being presented. What’s the plan to keep the air flowing into the engine clean? For example, on an O-320 with carb.
Thanks.

Yes, there are alternatives for the round K&N filters. Answered here: https://vansairforce.net/community/showpost.php?p=1637757&postcount=3
 
Last edited:
The K&N recharge kit we sell does indeed have a red color to the oil and after applied turns quite sticky.
Because of the way the K&N filter functions, I would not use one on my airplane without the proper (sticky) oil.
FYI everyone: About this time last year I'd started getting an engine "stumble" around 2100-2200 rpm when going to WOT for takeoff. Initially lasted about a second or two. It got progressively worse and worse. IO-360 engine.

But it only happened on the first application of WOT of the day. Subsequent WOT would be fine, like on touch and goes. I could do a quick WOT after engine run-up, get the stumble, go back to idle, taxi for takeoff...no stumble.

Two weeks ago I removed the fuel servo and divider, and sent them in for IRAN. Well...short story long...the diaphragm on the air side was gummed up with red goo, would stick to the center body. This caused the stumble.

I had installed a new K&N filter, right out of the box, oiled as-is, about two months before the stumbling started.

So just a heads-up: That red K&N filter oil IS sticky, as RV Builder states above. I've seen vids where after cleaning a K&N filter, they use WD-40. Don't know if this would cause goo problems or not. But that red stuff sure does.
 
Last edited:
Back
Top