4106 Air Cleaner

[Madmike]

I wanted to check my air filter to make sure that it was clean. This comes up from the engine and there are two round things next to where the air intake goes up. I took one of these off and found out it is full of oil. Is this right? I have zero experience with this.

[steve wardwell]

sounds like an oil bath filter. Remove, clean, clean, clean, reinstall with clean oil to the line. 

[Sam 4106]

If your 4106 hasn't been modified there should be 4 air cleaner canisters, two on each side of the air intake.
Good luck, Sam MC8

[JohnEd]

Hey you got the premo system.  Here is the straight poop.  drop that reservoir....bottom pan full of oil.  Pour off the oil into a separate pan.  Wipe out the bottom of the pan to get out the collected dirt and it might need scraping a little.  Don't give a thought to scratching the pain as it will be bathed in oil.  Now here is the really neat part...remember that oil you saved?.....put it back in cause it ain't worn out.  Then ADD oil to ONLY THE EXACT LINE.....NEVER OVERFILL ONE OF THESE or you will find out what over fueling really means.

These filters go a long long time between service and simply dropping the pan a few inches to verify that the oil is still deep and it isn't full of dirt is enuf.  Check the manual and find out what the service interval is for sure and I think you will find you can double it.  But sticking your finger in the oil and seeing if the muck is really deep is enuf for me.

Here is the real bugaboo:  You don't get to fork out $50 or 100 for a new filter that will pass less and less air till you have to replace it.  The oil bath has the same air restriction at the time it needs service as it did the day it was made or was last serviced..whichever comes first.

The servicing of the oil bath was considered so very filthy a job and took so much time that the industry switched to paper elements.  So how exhausted are you for having dropped that pan and discovered OIL IN THE BOTTOM.  Now if there was no oil in there you would be doing a lot of nail biting....really, a LOT.

I  have only glanced at a 4106 filter and that was a few years ago.  I think there were more than one section to the filter/ more than a single filter.  But I am glad to share with you the EXPERTISE I gained with my VW oil baths.  Cleaned and replaced the oil in one once.  The other 200 thousand miles I checked to see if there was still oil in the reservoir and that it was the correct level.  It always was.

I recently learned that oil bath filters are still used on farm machinery that works in, as you can imagine,  hellacious dust conditions.  Antique technology?  Archaic?  Dinosaur stuff?  I think not and engine life is my ONLY concern.

John

[gus]

Your manual should tell you exactly how to clean and refill them.

In my opinion these old oil bath cleaners are the best, no expensive paper filters to replace, just a bit of oil and elbow grease.

Be sure not to overfill with oil, it is easy to do.

[pvcces]

And if the air filter should trap some rainwater, it can become overfilled rather easily. This just might be one reason that these coaches had four of them. After all, they all run in parallel.

I think the service manual calls for new oil, but in this day and age, I can't see much reason for the requirement. We use some saved crankcase oil as makeup, so the four air cleaners take less than a half gallon for servicing.

We recently got back the report of an oil analysis and the report said nothing was needed to keep our oil clean. This, after 15k miles or so, since the last oil change.

For what it's worth.

Tom Caffrey

[Madmike]

JohnEd

Thanks for the good advice! When it is not a bilzillion degrees out I am going to take them all down and clean them out. She is a good bus but I am learning very slowly and every bit helps alot. Thanks again to everyone on helping me.

[Utahclaimjumper]

Mike, when your ready, contact me and Ill give you a hand, there are some other things you should know.>>>Dan

[JohnEd]

Mad Mike,

You are certainly welcome.  Like I said I am not anyone's idea of an expert.  Hope I stimulated some thought on the matter and got you more good advice.

The oil bath is a variant of the velocity filter.  That one, the VF, has the air go in a duct and then the duct takes a sharp turn.   At the turn, there is a large chamber.  The air makes the turn just fine but the dirt, having more mass, continues into the chamber and settles to te bottom void.  This  is the method in some farm machinery I have seen. The straw and bits and sand go into the velocity filter chamber and that might be emptied every hour or daily, depending on conditions.  After the velocity filter the fine particulate filter processes the air.  In the oil bath the air is ducted directly AT the oil pool and then the air takes a sharp turn.  Almost anything with any mass gets flung at the oil surface, sticks, and is trapped and settles to the bottom.

You can WIKI the filter.  Its interesting technology, particulate in view of so many running the technology down.

Share what you learn, in you investigations, with us. Please.  Wh Knu you should be so interested in air filters and their alternative designs?  Hu Nu?

John

To process all the air a 8V71 might draw, the filter has to be of a size that will not present to great a resistance to good flow.  Conversely, if the oil bath is too large, the air will be traveling too slowly to get a"good fling" on the particulate and the particulate will make the corner and proceed into the engine.  I have heard that all those filters in the 4106 are set up to run in PARALLEL...side by side.  Can you imagine how much sense it would make to employ a mech that would open the duct for each filter, in turn, as the air flow volume demanded?  That's just my rumination on how best to provide low restriction air flow ad still get opt filtering.  I wish I had a 4106 manual to lok at the filter design.  Any body?

[Utahclaimjumper]

With the 4106 there really is more to it than that, the can holds a metal mesh and screen that also seperates the dirty air and "filters" before its forced to be SUBMERGED into the oil and comes out cleaner.>>>Dan

[Utahclaimjumper]

As a side note when cleaning the filter cans, water is heavier than oil, so all moister lays on the bottom of the cans and will rust thru the bottoms. After cleaning the cans inspect for pits in the bottom and apply a protectrant to the bottom to prevent any farther corrosion.>>>Dan

[JohnEd]

Dan,

I think you will find that the filter does not work that way.  The air passes thru to the oil before it goes thru any mesh.  After making the turn and getting rid of the dirt the air turns around and then passes thru the mesh.  With all the air flow and vibration and such there is a very small amt of oil that gets sucked up into the mesh.  The mesh is there to collect that oil and then to provide a final stage of filtering cause it has some oil on it.

The air DOES NOT bubble up thru the oil.  That would create a huge amt of resistance to flow and the air starved engine will run very rich.  Don't ask me how I know this and am so certain.  Fill only to the "full line".

John

[gus]

I had the same thought about used oil in the air filter but changed my mind when someone on the forum told me the reason for using new oil. He convinced me and I'm a born skeptic!!

Briefly, what I remember about how an oil bath filter works is most of the heavy dirt is caught in the oil reservoir when the air reverses direction at the bottom. The incoming air then pulls oil up onto the vertical mesh which catches the remaining dirt in the air. If this oil is already dirty it can't do a very good job. This is also the reason not to overfill the bottom pan because it will choke off the air and also, less air can't pull up the proper amount of oil.

That is a very good point about rusting through at the bottom. One of mine leaked when I first got the bus but the PO gave me another one from his parts bus. These leaks are usually pretty easy to plug because they are so small, sometimes a small SS screw with a soft washer will do the job.

I didn't go into cleaning the mesh because it is pretty obvious when you remove the bottom plus the MM gives complete instructions.