# Does anyone use a outer and inner air filter



## marc_hanna (Apr 10, 2017)

Hi all,

Does anyone use an outer and inner air filter combo on their tractor? It seems like it's generally optional. Just wondering what everyone's experience is, such as better filtration versus poorer fuel economy, etc.


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## Hoodoo Valley (Nov 14, 2006)

My John Deere 990 has a dual element and honestly, the inner element has never shown signs of getting dirty. My Kubota BX 2200 has a single filter element.


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## Groo (Jan 17, 2020)

Aren't they two different filtration ratings? The outer handles the course and the inner the fine?

The OEMs do it like that for a reason. That sure isn't the place I'd try to pick up 1/10th of a hp at.

Eta, not too surprising that a bx would go creap on the air filter. They are overgrown lawnmowers (no offense intended) and were never intended to spend thousands of hours kicking up dust in a field. And of course filter tech is improving.


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## marc_hanna (Apr 10, 2017)

Both my Kioti and Kubota use the same air filter, and neither came with the inner filter. The outer filter on both is normal filter media and it seems to me, if i used the second filter, it would be very restrictive.


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## pogobill (Jan 31, 2012)

I wonder if the air filter canister is even set up for the double filter? My Case has the double filter set up.


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## marc_hanna (Apr 10, 2017)

The Kioti manual describes it as optional for dusty environments, but the Kubota manual has no info on air filter at all, except when to change it. Having never used the dual filter before, I wouldn’t even know what I’m looking for to see if they are set up for dual filters. I just assumed one interlocked into the other


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## pogobill (Jan 31, 2012)

My air filter canister has a "cup" that the filter seats into to make a seal at the bottom end. There is also another "cup" in the center of the bottom end, about the size of a spray paint can lid, for the inner filter to plug into.


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## marc_hanna (Apr 10, 2017)

I’ll have to take a look when I replace them. The outer filter on its own seems to be doing the job and I dont operate the equipment in what I would consider a dusty environment.


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## HarveyW (Sep 15, 2014)

My John Deere Z-Trac mower has the dual filter arrangement. I blow the dust out of my outer filter periodically, with compressed air. IMO, the inner filter has one purpose. If you ever see any dirt on the inner filter, this means your outer filter is leaking and must be replaced immediately. The inner filter provides some backup to protect your engine till the filter elements are replaced


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## DK35vince (Jan 22, 2006)

My Kioti ( 2001 DK 35) came with inner and outer filter.


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## Groo (Jan 17, 2020)

often you can get the same engine with a a couple of different air filter options.
The sawmill I run has a dual filter for it Kohler Command big block twin, CH940 32hp IIRC. I know the same engine is used in equipment with a single filter, and I think there are more than 2 options.


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## marc_hanna (Apr 10, 2017)

I think I’ll add the second filter and give it go.


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## Bob Driver (Nov 1, 2017)

Heavy equipment operating in landfills and rock quarries run in about as heavy of a dust environment you'll ever find and they always run dual filters. They also run filter restriction gauges (Filter Minder). If you don't currently have one, they're easy to plumb into the system and they run about $15.....










http://filterminder.com/products/vi...triction-monitoring-gauge-threaded-mount.html


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## FredM (Nov 18, 2015)

My Kubota B2400 has both filters plus a cyclone built into the end of the air filter housing which will remove a good percentage of the dust before reaching the outer filter.


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## marc_hanna (Apr 10, 2017)

Bob Driver said:


> Heavy equipment operating in landfills and rock quarries run in about as heavy of a dust environment you'll ever find and they always run dual filters. They also run filter restriction gauges (Filter Minder). If you don't currently have one, they're easy to plumb into the system and they run about $15.....
> 
> 
> 
> ...


I’ve got one of those on my cummins. I usually change my air filters out long before it shows in the red.


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## marc_hanna (Apr 10, 2017)

FredM said:


> My Kubota B2400 has both filters plus a cyclone built into the end of the air filter housing which will remove a good percentage of the dust before reaching the outer filter.


It seems to be the general consensus that everyone has both.


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## Bob Driver (Nov 1, 2017)

marc_hanna said:


> I’ve got one of those on my cummins. I usually change my air filters out long before it shows in the red.


Yep... Most people do, that is unless you're running a fleet of 1,000 OTR tractors with a set of air filters running about $100 to change for each unit. That's $100,000 worth of air filters. You can piss a whole bunch of $$$ money away by not changing them until the Filter Minder hits 22".

Donaldson designs/builds the air intake systems for just about everybody now days. They say change at 22" of H2O in all of their service literature. I've actually been to several Donaldson seminars where they said their air filters don't actually hit their peak filtration efficiency until about 11"


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## john wappes (Apr 3, 2020)

marc_hanna said:


> Hi all,
> 
> Does anyone use an outer and inner air filter combo on their tractor? It seems like it's generally optional. Just wondering what everyone's experience is, such as better filtration versus poorer fuel economy, etc.


John Deere started using two air filters in the late 60^s
Normally change inter filter 1/3 as many times as the outer or unless noticeably dirty.


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## EZE (Jan 23, 2020)

It depends on the environment you are using your tractor. My rule of thumb would be, if the environment is not too dusty, and you have a pre cleaner (a centrifugal air intake adapter as seen on most all industrial and ag tractors), then an inner filter should not be necessary. But if the environment is dusty, then I would go for the inner filter. The difference in the amount of air being inducted through multiple air filter elements as opposed to one, would be negligible, unless they were both dirty or have excessive amounts of moisture in them. Another consideration should be the type of dirt in your working environment, as some dust particulates are of different sizes than others. Others here have said that the inner filter is just a safety filter, and I agree with that mostly. While I am not an expert trained mechanic, I am of the opinion that the inner filter does catch certain size particulates that can, and do pass the primary, as this only makes common sense, as mentioned here, the filter media does have holes in them to allow for air to pass. But those "holes" are very small. I imagine there are equally small dust particulates that can pass the primary filter media. Just because there is no visible dirt in the inner filter, doesn't mean that there is no dirt in the media, just that it is not visible. But to be honest, dust of this size should not be of too much concern, if any. Also, you may wish to invest in a pre cleaner as opposed to an inner element, as this would be your first line of defense in your air intake. Many of the OEM pre cleaners are not very good (cheap). If your tractor does have a pre cleaner, you can compare what you have on your tractor to the pre cleaners found in your tractor store or online as a way to determine if you should replace the OEM one (if you are in doubt, I suggest taking a picture of your pre cleaner and posting it here and getting some advice as to whether you should replace it or not). Also, you should not attempt to clean an inner filter. If there is visible dirt/dust on an inner filter, just replace it, as inner filter medias are not designed to be cleaned, unless there is some product out there that I am not aware of that calls for it, but I have never seen a "cleanable" inner air filter element in my 35 years of being a heavy equipment operator.


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## Busted Tractor (May 22, 2018)

In my 40 years working with MF MM Oliver and others I have seen most harvest equipment come with the outer element and as they called them a safety or inner element. Most but not all tractors had just the outer element but had a safety element as an option. With this knowledge no the outer filter is not a course dirt remover and the inner in not a fine dirt remover. The outer element is THE main filter which was explained earlier. It is a safety element in case the outer element gets a hole in it or leaks at the seals. The outer element is supposed to be cleaned when it becomes plugged or extremely dirty that is why they started using those restriction indicators. The inner element is only supposed to be changed when the outer element replacement does not "fix" a restriction. It is NOT recommended to over service the outer element too frequent cleaning can break the filter media loose, especially using an air compressor or bumping the element on a tire. Donaldson had made a special soap powder to mix with water and wash them. Some folks used just a mild detergent and it worked fine. After cleaning the recommended using a light inside the filter to look for holes and tears. One caution though be sure the filter is completely dry be fore using it. Most folks on combines had two elements one to wash and dry and one in the machine. To help keep the filters from needing too frequent cleaning they installed many types of precleaners, most were a centrifugal type that spun the air and then ejected dirt or collected it in a bowl and then needed to be emptied.


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## LouNY (Dec 15, 2016)

If your filter housing is set up for an inner and an outer filter in my mind it would be foolish not to use both, I blow my outter out with an air nozzle carefully, If the inner is showing dirt and dust I change them both as the outer should have caught all the dust the inner is a safety filter.


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## sleepylizard (Dec 28, 2016)

LouNY said:


> If your filter housing is set up for an inner and an outer filter in my mind it would be foolish not to use both, I blow my outter out with an air nozzle carefully, If the inner is showing dirt and dust I change them both as the outer should have caught all the dust the inner is a safety filter.


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## sleepylizard (Dec 28, 2016)

Unless you're in a real dry & dusty area, I believe that you are better off with a good pre-cleaner (Donaldson are good). I service a Gregoire grape harvester through the annual vintage in the Mildura area each year, and the pre- cleaner gets most of the dust, then I blow out the outer filter. This is done every day. The inner filter gets replaced once per year whether it needs it or not. All the earth moving equipment in this area also run pre-cleaners.


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## Eldog (Apr 30, 2019)

marc_hanna said:


> Hi all,
> 
> Does anyone use an outer and inner air filter combo on their tractor? It seems like it's generally optional. Just wondering what everyone's experience is, such as better filtration versus poorer fuel economy, etc.


Deutz air-cooled tractors use this configuration and it works well. These tractors have some of the best fuel economy statistics in the industry


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## John Liebermann (Sep 17, 2018)

I would think especially if you are in dusty conditions. There is no way the engine can get "too clean" air.


sleepylizard said:


> Unless you're in a real dry & dusty area, I believe that you are better off with a good pre-cleaner (Donaldson are good). I service a Gregoire grape harvester through the annual vintage in the Mildura area each year, and the pre- cleaner gets most of the dust, then I blow out the outer filter. This is done every day. The inner filter gets replaced once per year whether it needs it or not. All the earth moving equipment in this area also run pre-cleaners.


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## IHRedMan (Mar 4, 2018)

My Cub Cadet lawn tractor has an outer and inner filter. I have had to change the outer foam filter because it disintegrated, but the paper filter was ok. When you get a new Kohler filter, they sell you both, like it or not.
I like my Ford 2000 air filtering system, cyclone cleaner on the hood an oil bath in the radiator area. Cheap to change. Can’t say that about the Kohler filters!


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## EZE (Jan 23, 2020)

Busted Tractor said:


> In my 40 years working with MF MM Oliver and others I have seen most harvest equipment come with the outer element and as they called them a safety or inner element. Most but not all tractors had just the outer element but had a safety element as an option. With this knowledge no the outer filter is not a course dirt remover and the inner in not a fine dirt remover. The outer element is THE main filter which was explained earlier. It is a safety element in case the outer element gets a hole in it or leaks at the seals. The outer element is supposed to be cleaned when it becomes plugged or extremely dirty that is why they started using those restriction indicators. The inner element is only supposed to be changed when the outer element replacement does not "fix" a restriction. It is NOT recommended to over service the outer element too frequent cleaning can break the filter media loose, especially using an air compressor or bumping the element on a tire. Donaldson had made a special soap powder to mix with water and wash them. Some folks used just a mild detergent and it worked fine. After cleaning the recommended using a light inside the filter to look for holes and tears. One caution though be sure the filter is completely dry be fore using it. Most folks on combines had two elements one to wash and dry and one in the machine. To help keep the filters from needing too frequent cleaning they installed many types of precleaners, most were a centrifugal type that spun the air and then ejected dirt or collected it in a bowl and then needed to be emptied.


So, if you replace the outer filter, and that does not fix the restriction you replace the inner filter as well, aren't you saying that the inner filter is restricted? Doesn't that mean there is dirt in it? Like I said, I agree that the outer is the main filter, but to imagine the inner FILTER is not doing any filtration at all does not seem logical to me. But again, I am not an expert mechanic, just a journeyman operator that has maintained many pieces of equipment over the years. By the way, for what it's worth I feel like IHRedman that oil bath pre cleaners are great, and cheap, but OEM's always look for ways to make more money. So inner filters may just be another way for them to make more money! I have yet to see an outer/main filter get a hole in it or fail, unless the hole was put in it by someone while cleaning it. Not saying it does not happen, just that I have never seen it.


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## tater415 (Sep 30, 2021)

I just bought a brand new kioti rx7320 tractor. I went to clean the air filter for the first time and noticed it only has one filter element. but it has a spot in the canister for a secondary filter, since I live in Southern California and it never rains here, everything is extremely Dusty. I ordered a replacement primary filter and a inner filter which they do make the inner filter


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## SidecarFlip (Mar 25, 2021)

tater415 said:


> I just bought a brand new kioti rx7320 tractor. I went to clean the air filter for the first time and noticed it only has one filter element. but it has a spot in the canister for a secondary filter, since I live in Southern California and it never rains here, everything is extremely Dusty. I ordered a replacement primary filter and a inner filter which they do make the inner filter


Good idea. Every Kubota I've owned has both. Turbo charged and naturally aspirated and Donaldson make all the filter cannisters for Kubota btw. Probably for Kioti as well. I chage my inners ever few years, outers get blown out with low pressure compressed air often (I farm with mine) and replaced ever 2 years no matter what. Diesels by their very nature will only have a power loss form a dirty air filter, if the filter is totally clogged. and it it was is, the engine would suck the filter media out of the filter (why diesel filters usually) have wire mesh over the media and inside the filter media as well.

Kind of unpleasantly surprised yours didn't come with an inner filer in as much as the air cleaner has the spot for it.


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## Busted Tractor (May 22, 2018)

Years ago when I was working with farm equipment the outer filter was referred to as the air filter the inner filter was referred to as the safety filter. 
The Main filter is supposed to do all the filtering the safety element was only used in case the outer filter leaked. 
We were taught to clean the outer element either with low air pressure and never blow directly at the element or by washing the element and allowing it to dry, thoroughly inspecting the filter before reusing it also not if washed it has to be dried completely. 
If any dirt was viewed on the safety element it and the main element is to be replaced immediately as the outer element is leaking. 
Some folks over serviced the air filters causing dirt to enter the engine, this is why restriction indicators are used some are self contained and turn red when the filter begins to plug or there may be a light that glows when the filter gets restricted. 
Do you self a favor and do NOT over service the filter, it can be worse than not servicing it. Over servicing can also cause issues with dirt entering the engine when the filter is removed and reinstalled and can cause problems with the seal on the end of the filter.
Manufactures often recommended a precleaner for dirty, dusty conditions. They clean the air before it even gets to the air filter. Some were of the plastic bowl that had to be removed and dumped occasionally, there were Tubo precleaners that used an internal fan to "blow" the dirt out of the air, then there were the aspirated precleaners that spun the air and used a vacuum ejector on the exhaust to remove the dirt. 
No matter the "dry type" air filter beats the old oil bath air cleaner for servicing any day!


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## SidecarFlip (Mar 25, 2021)

How Kubota refers to the 2 filter system and I have the filter minder gage on both my M's. According to Donaldson a dirty (but not caked up) air filter cleans better tan a clean one. I put a bit of chassis grease on the base on mine when I install them, makes installing them easier in the molded cups in the air cleaner body. Tight fit.


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## Tx Jim (Jul 28, 2020)

My '91 JD 4255 came with outer & inner(safety) filters when it rolled off the assembly line. I had pistons/liners installed @ 11,400 hrs of use in Spring 2000 due to failed piston liner sealing ring. Engine before OH only used a quart or 2 of oil between oil changes. My '11 Kubota M7040 has inner & outer air filters.


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## SidecarFlip (Mar 25, 2021)

Interesting Jim. Neither of my Kubota's at 6000 and 3000 hours use any oil between changes or I should say very little. All engines consume a bit of oil, it's the nature of a 4 stroke engine be it gas or diesel. Far as economy goes (fuel used per hour), any mechanically injected pre 4 engine will always be more fuel efficient that a late model post 4 emissions engine because they all use diesel fuel in the oxidation process of the accumulated soot so fuel efficiency (used per hour) will drop.

Have a friend with a pair of 4020 JD's he uses in his produce operation to mostly pull wagons and some light tillage and both have rolled over the hour meters with very little major issues. I find that pretty amazing. I believe both have had in frames but neither have had the engines out.


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