C12 air filter and muffler

[Jeremy Parrett]

I have a 2000 Marquis Amethyst with the 1999  Caterpillar C12 450hp engine. I am not savvy with the mechanicals yet. Can someone tell me where the air filter is (diagram) ,what it looks like and how easy is it to replace the filter? Air enters the side of the coach through a grill ; is ducted to a black box 4inX8inX18In mounted right side of the engine right behind the door , then from the bottom of this box it goes to a large round cylinder at the bottom of the engine bay and then up and over the engine to the turbo.
I have read about a K&N replacement that coupled with a muffler will help with fuel economy.
 Thanks,  Jeremy

[Richard And Babs Ames]

Welcome to the Beaver Ambassador Club Forum. If you put the year model in your post it would be very helpful. In later models it is a Donaldson or equivilant modular round and long filter at the rear of the coach and accessible when you lift the rear access door. It has a fresh air intake and exit to the turbo on your engine.

Modular means the whole metal canaster and element is replaced and not just the filter media. That translates to well over $100 instead of under $50. I just bought one for our Patriot that listed for $249 but the parts house sold it to me for $149.

[Edward Buker]

On the passenger side rear of the coach will be an air inlet. Follow the large piping leading from that inlet until you see a large canister. That will house the air cleaner. It could be a metal unit where you loosen a ring and separate the housing on earlier coaches or it could be a plastic housing with wing nuts on the bottom that you turn to release a cover. There may be other styles I am not familiar with but in all cases it should be easy to determine how to remove a cover system. In all cases it is not too hard to change the filter.

Regarding better mileage by changing components. My guess is it would be a subtle difference at best. Weight, frontal area, rolling resistance, are the main issues. Air flow resistance of these components is probably a minor offender in the total equation.

later Ed

[Gerald Farris]

Changing the air filter to a low restriction air filter to increase fuel mileage has the down side of not filtering the air as well and therefore increasing engine wear from the increase in dirt that the engine will ingest. It is also very doubtful that you would ever save enough on fuel to pay for the cost of the filter. So I would not recommend the low restriction air filter on a C-12 that originally had a very adequate intake system.

On the other hand a low restriction muffler has no downside other than increased noise levels, especially when the "Jake Brake" is engaged. A low restriction muffler will increase the efficiency of the turbocharger and therefore give a slight increase in power and fuel mileage, if you do not mind sounding like a truck.

Gerald

[LarryNCarolynShirk]

I installed both an oil air filter and a turbo muffler on our coach.  I think the mileage increased about 3/4 MPG (7.7 to 8.5) , improved acceleration, and gained about 5 MPH on hills.  Even Carolyn noticed a difference in performance.

It may have some drawbacks in engine life, but I won't last for ever either.  The noise is at the rear of the coach, and not noticeable in the coach at highway speed.  When the Jake is applied, the noise is apparent.  All was worth it to me.

Larry  

[Edward Buker]

Gerald,

While we are on the subject of air filters. I have noticed with a new standard filter put into the coach at the PDI that my restriction indicator normally rose to a yellow indication from the start. If I reset, it will rise to the same level, no better and no worse over 11K miles of use. Is this normal for the amount of airflow required by the C12 with this intake system?

 I plan on replacing the current filter with a Donaldson Endurance filter which shows a less restricted flow as contaminants plate the media as well as more effective filtration. I had one on my last coach and found no downside unless your experience has indicated otherwise.

http://www.donaldson.com/en/engine/support/datalibrary/000165.pdf

Later Ed

[Gerald Farris]

Ed,
I know of no downside to the air filter that you mentioned. I have been running one for 4 years, and I am pleased with it's performance.

Gerald  

[Jeremy Parrett]

Thank you all for your suggestions.  Jeremy

[Jeremy Parrett]

My coach is a  Marquis Amethyst 2000 .  I finally  changed the engine air filter. The drum shaped container is low down on the passenger side of the engine bay. It is easily accessed from under the coach.  
  Thanks for all the great advise.  jeremy

[Don Voss]

Ed,

I wanted to get the Donaldson endurance air filter for my 2004 Marquis C-12.  I am told by Donaldson that I have to use the standard Donaldson on my coach.  My manual indicates I use the Donaldson p537448.  It doesn't seem to cross referance with the Endurance model.  What did you go through to get one for your coach?  Mine may be a different set up.

Thanks

Don Voss

[Edward Buker]

Don,

This is the cross reference list that is on the web and I did not see your filter number listed. I would call Donaldson and see if they have one or plan on having one. It may be that volume does not warrant them producing one or the list is not complete.

http://www.donaldson.com/en/engine/support/datalibrary/000834.pdf

They have an 800 number at the bottom of the literature in the link. I went to this filter from a Fleetguard because of its better filter properties. I was hoping that my change indicator, that always runs a notch or two in the yellow, would hit the green with a new filter but it is running the same. That is my baseline with a new filter and the built in restrictions of our air intake system.

Later Ed

[Don Voss]

Ed,
Thanks for the info.  I called Donaldson and they don't have the Endurance model for my type of filter.  i guess I'll stick with what I had.
Don

[Jeremy Parrett]

I installed both an oil air filter and a turbo muffler on our coach.  I think the mileage increased about 3/4 MPG (7.7 to 8.5) , improved acceleration, and gained about 5 MPH on hills.  Even Carolyn noticed a difference in performance.

It may have some drawbacks in engine life, but I won't last for ever either.  The noise is at the rear of the coach, and not noticeable in the coach at highway speed.  When the Jake is applied, the noise is apparent.  All was worth it to me.

Larry  

Larry,
 do you have the specs for the muffler and air filter you installed.   Thanks, Jeremy

[David T. Richelderfer]

My coach has an AFE oiled air filter and an aftermarket muffler.  The conical shaped air filter is removable from its metal cylinder, cleaned with a detergent spray, rinsed completely, let dry overnight, then re-oiled before replacement in the metal cylinder.  The whole metal cylinder is removed from the engine compartment before the filter is taken out of the cylinder.  I have no idea what the muffler is.  As you noted, I am also told the engine exhaust noise is pretty loud when accelerating and even louder when the jake brake is engaged.  I can notably hear the exhaust noise under acceleration and jake braking if a side living room window is open.  Otherwise, I cannot hear it much.  I am aware that heads turn on the roadside from the noise as I pass by.  I always comply with the "No Engine Brakes" signs when entering cities.

[LarryNCarolynShirk]

Jeremy,

I do not have all the paperwork with me, but I recall it was an Aero muffler, which you can find here:

https://www.aeroexhaust.com/

The air filter was a competitor of K & N and very similar.  Both were sold by a vender that has attended many FMCA rallies in the past.

If I locate more information, I will post it.

Larry