Oil Bath Air Cleaner - Service Questions

richard5933 · September 16, 2019, 11:49:43 AM

My 4108 has an oil bath air cleaner. Just one really big oil bath air cleaner. No interest in changing to paper filter, that's not the focus of this post.

I've been servicing the oil bath air cleaner regularly, dropping the pan to empty the dirty oil and clean the pan, and then removing the bottom (removable) screen to clean it. Then the oil gets filled and all gets put back together.

There is also a mesh permanently mounted in the upper canister portion which stays in the bus when the lower section is removed. The manual mentions that when build-up is noticed it should be removed for cleaning.

Not too worried about it right now, as there is only a little dirty oil inside the intake tube and no visible build up on the mesh. Remember, only about 50K miles on the bus and no history of operation on dirt roads. But, I'm curious about two questions...

1) Just how dirty does the upper section need to be to justify pulling it down and cleaning it?

2) How does the darned thing come out? The oil pan itself is difficult to get out without removing anything, and I can't see how the canister comes out without taking something else out first.

lostagain · September 17, 2019, 06:16:32 AM

The upper screen catches oil mist, that in turn catches any dust that got past the oil bath. So some oily dirt is ok. When I had an oil bath air cleaner in my 57 MCI Courier 96, I would occasionally take the whole thing off the bus and clean it with solvent or diesel fuel.

JC

DoubleEagle · September 17, 2019, 07:39:35 AM

I realize you said you had no interest in changing to a paper filter, but it really sounds like servicing your oil bath type is not very convenient. It has been pretty well established that the paper filters are more efficient at keeping dust out of the engine, so the illusion that the good ol' oil bath is good, does not serve the engine well. If there is a way to put on one of the ECO disposable filter kits (like Cliff recommends), it would ease your filter maintenance.

chessie4905 · September 17, 2019, 08:48:53 AM

There is PLENTY of room for one. That oil bath is huge. They also made a version that used a paper element, and overall about the same size as the oil bath one.

dtcerrato · September 17, 2019, 09:00:24 AM

Richard we both own GMCs. Don't know how different your 4108 oil baths are to our 4104. The elements above the oil pan slide down & out of ours. Not easy if they've never come out. We clean our elements in gas or diesel everytime we do the oil change. If the oil baths in general is regularly maintained, cleaning (maintenance) is absolutely trouble free. Have you looked at your "exploded parts view"? I find the parts manual really compliments the maintainence manual - especially the oil baths sections... fwiw.

richard5933 · September 17, 2019, 10:36:09 AM

Quote from: chessie4905 on September 17, 2019, 08:48:53 AM
There is PLENTY of room for one. That oil bath is huge. They also made a version that used a paper element, and overall about the same size as the oil bath one.

I know a paper filter element is available. I checked with Luke to see if it is worth changing over and the answer was no.

Quote from: dtcerrato on September 17, 2019, 09:00:24 AM
Richard we both own GMCs. Don't know how different your 4108 oil baths are to our 4104. The elements above the oil pan slide down & out of ours. Not easy if they've never come out. We clean our elements in gas or diesel everytime we do the oil change. If the oil baths in general is regularly maintained, cleaning (maintenance) is absolutely trouble free. Have you looked at your "exploded parts view"? I find the parts manual really compliments the maintainence manual - especially the oil baths sections... fwiw.

The 4108 has a single very large oil bath air cleaner, about 16" in diameter and about 20" tall. Once the oil pan is removed, there is a "pre-filter" which comes out with three thumb screws. It's what you see in the first photo. In the second photo you can see the part which is inside the canister. It is not removable on its own - you have to drop the entire canister out of the engine bay to clean it. It's big and there's not much room around it.

I don't have a problem servicing the oil bath air cleaner, and doing the bottom "pre-filter" and changing the oil only takes about 15 minutes and costs nothing more than some discount motor oil to fill the pan.

My question was about when is it time to pull the canister and do a complete cleaning. The manual doesn't really specify a timetable for this, just to do so when it's dirty. No real definition of dirty. I was curious what the consensus is for how often to service the upper canister. Since it will be a PITA to pull out, I obviously don't want to do it more than necessary.

buswarrior · September 17, 2019, 10:59:23 AM

It can't be any worse than what the guys with the stock paper filter have to do...

Same giant can, and it all has to come out to change the filter.

Unknown life, the PM schedule is meaningless, even if it was better defined.

Get it out and zero your maintenance.

Job done.

Happy coaching!
Buswarrior

luvrbus · September 17, 2019, 11:43:06 AM

Never knew why people cannot understand that oil bath filters only filter 94% of dirt out of a engine and that is at full throttle only.LOL we went through this over and over. DD recommends paper sure they are not Luke but they did the research and sent out the engineering bulletin's for what best for a air hog 2 stroke engine,oil bath filters on a curve and paper filters on a straight line at all speeds that's all folks

chessie4905 · September 17, 2019, 12:21:38 PM

You have to be careful with paper filters ingesting moisture and start to disintegrate and be injected into engine. There have been reports in the past here that SOME have had it happen.
Richard, just pull it apart and service it. Then you can go on to the air compressor muffler, the rebuild of the air brake components, etc., per your service manual.

luvrbus · September 17, 2019, 01:04:16 PM

Quote from: chessie4905 on September 17, 2019, 12:21:38 PM
You have to be careful with paper filters ingesting moisture and start to disintegrate and be injected into engine. There have been reports in the past here that SOME have had it happen.
Richard, just pull it apart and service it. Then you can go on to the air compressor muffler, the rebuild of the air brake components, etc., per your service manual.

Engines are lost every day by water in oil bath filters, I never saw a engine destroyed by a paper filter

paper filters have a water drain or a valve.When I tear a engine down it is clear which filter is used but people have the choice on what they use

richard5933 · September 17, 2019, 01:19:32 PM

Quote from: luvrbus on September 17, 2019, 11:43:06 AM
Never knew why people cannot understand that oil bath filters only filter 94% of dirt out of a engine and that is at full throttle only....

It's not a question of understanding things - I don't doubt that the paper filter does a better job of cleaning the incoming air. I guess for some (like me) it's a question of prioritizing what can be done now vs. what has to wait, combined with the fact that some of us are working alone, outside, without the benefit of a shop where things can be fabricated. If the stock filter can be made to work for now then that's the plan.

If/when I decide to change to a paper filter I want to make the change in a way that is as close to the look and layout of the OEM. Since I tend to over research these things, it may be a few days till I decide to make the change. As many have said over the years I've been reading this and other sites, these buses have driven millions of miles on the oil bath setup all across the country. I seriously doubt the relatively few miles I'm going to drive on paved roads are going to overtax the ability of the oil bath air cleaner to get the job done.

The upper section of mesh seems clean to me. The oil dripping from it is glistening and not cloudy, looks about as clean as oil droplets can. There is no visible dirt build-up on the bottom of the upper section where the airflow goes in. I've serviced the lower section and will wait on the upper till spring.

Now all that said, if someone has a bolt-in option for changing to a paper element filter I'm all ears.

chessie4905 · September 17, 2019, 01:42:10 PM

Clifford, have you forgotten about the one reported here a couple years ago? After distengrating and collasping, no filtering done.

luvrbus · September 17, 2019, 02:00:04 PM

Quote from: chessie4905 on September 17, 2019, 01:42:10 PM
Clifford, have you forgotten about the one reported here a couple years ago? After distengrating and collasping, no filtering done.

A paper filter will plug and kill the engine,there is no way it can enter the engine unless some idiot for got to install the screen under the blower.I rebuilt a 8v92 that had a rag or 2 left in the cooling system now that will destroy a engine paper filters noway that argument went no place except the BS files on the paper filter destroying the engine in the 4106

buswarrior · September 17, 2019, 04:35:05 PM

Quote:
Now all that said, if someone has a bolt-in option for changing to a paper element filter I'm all ears.
Unquote

You better look at the "period" ones and think again, total disassembly to change, and what, 10 bolts to take the lid off?

Choosing a newer one that fits and slides out sideways with 3 clips beats old school.

Happy coaching!
Buswarrior

chessie4905 · September 17, 2019, 04:37:49 PM

Of course the paper didnt hurt the engine. The dirt and debris that was then allowed to pass did over time.