CAT muffler

[Don Forsyth]

I have a 2005 Beaver Monterey Laguna IV with the C9 CAT 400. I have owned this since 2021 but had my first emissions test done in February 2022 in Colorado and then again in 2023. I went in to have it tested this week and was told everything passed except the muffler. They told me it must be a custom conversion or something, it was not like any CAT muffler he had seen before and it was missing the Catalytic converter.
I later looked at  the muffler and looked at it and the way it was installed. In my opinion, this is a stock muffler and has been on there since the day this coach was built. I also found the CAT number stamped on the Muffler, but it was really hard to read. I tried to look it up on the internet but had not luck. I called Caterpillar here in Denver and they tried to cross reference the numbers. Also no luck. But I was told that most of the CAT mufflers had converters in them. So my question is, Does anyone know what muffler I should have on my rig and what do others have.  Maybe Dave or one of the other owners has come across this before. Maybe someone has the same muffler I have and could give me the numbers off of it. I will try to attach pictures of what I found.

 The numbers that I copied off of the muffler were.  CAT  257 842  K 294         NCI 0035009 42 04

Thank you,
Don Forsyth

[Joel Ashley]

Don, others here can probably offer more specifics, but reference this thread:
http://beaveramb.org/forum/index.php/topic,7661.msg55822.html#msg55822

I can't be certain, but the "Diesel Oxidation Catalyst" or "DOC" may be inside the muffler, as others told you.  You may be just fine if the tech at the emissions test had never run into an internal one before, and you can point that out to them.  Of course it's entirely possible a previous owner replaced the original muffler with a cheaper one sans DOC.  This company may be some help, and there are others;  regardless they ain't cheap:    https://www.nettinc.com/information/emissions-faq/what-is-a-diesel-oxidation-catalyst

In the Portland area our coaches only need to be certified once and don't need to go through testing like other vehicles.  It was difficult, though the first time, because DEQ wasn't necessarily properly prepared for our type of vehicle.  I had to have some help from inside the system to prove to DMV I didn't, by their "fine print" regulations, need testing.  Not everyone in govt. employ is always up on things.  So you may have to do some homework to resolve your test department's initial assessment. 

Also, here's an informative piece for those of us that own but aren't C9 experts:
https://www.youtube.com/watch?v=Bn33Jf0wWY4

Joel

[Jim Nichols]

You have the original as built platinum lined muffler. Hopefully others write with pictures. I can not as my coach is in storage. I had removed ours years ago but after having sensors going bad, Dave Atherton encouraged me to go back to the original. The technician may not have experience with the older C9s.

[Don Forsyth]

Thank you for the information. CAT Man is one of my favorite. If it weren't for him I would not have been able to diagnose my check engine lights and would not have known what sensors change and where they where. I can see I have some homework todo on this muffler.
Jim, you say that this is the original as built. Do you know if it has the converter built in?
I am having a hard time understanding why the converter makes a difference if the emission test comes within specs. Just my ignorance speaking.

[Joel Ashley]

Looks to be the same as mine (original).  Should be fine as is.
Joel

[Jim Nichols]

03,4,5,6 and I think 07 the emission requirements didn’t use converters in the exhaust system. 08,9 and 10 was the regen system . Then came more sophistication. You are legal as is. Some states are changing the rules for older engines but mostly the commercial over the road.  So far recreational older engines are exempt.

[Scott Shearer]

Here are a couple of links containing Caterpillar ACERT and RV C9 information.

First link:
Circa 2003 video from Caterpillar that provides a high-altitude overview of Cat ACERT engines. It clearly shows that aftertreatment (catalytic converter) was used pre-DPF.

Second link:
Cat RV C9 spec sheet. Lists Diesel Oxidation Catalyst (catalytic converter) as required equipment.

-Scott

https://youtu.be/djWN_HGYbF0?si=7CEZs55tpQgMD5WK

https://www.rvtechlibrary.com/engine/Cat_C9_Specs.pdf

[Jim Nichols]

Platinum lined muffler creates hotter exhaust that’s why they could call it catalytic exhaust muffler back then . It is nothing like the honey combed type on cars and diesel pickups. In the first video it said the muffler would last the life of the engine. The whole reason for the original post was the mechanic said he needed one or it was missing.

[Joel Ashley]

I think Scott's first video says it well enough near the end... there is no separate converter needed on that ACERT era.  None is seen on my original system.  You just need to convince your air quality department of what they should already be aware of.

Revisiting my previous note, in 2016 I got confirmation from our Oregon DEQ dept. that our coach met their heavy duty diesel (over 8500lb GVWR) guideline, and I completed a Declaration of Exemption form.  A Certificate of Compliance was issued, as is normally done with each 2 year test of most vehicles, but this one was put on permanent file.  Reregistering every 2 years now requires DMV to only reference that file to verify air quality regulation compliance, and the coach does not need to actually be tested.  Don, you should inquire whether Colorado may have similar procedures.  My contact that expedited things was with DEQ, not DMV;  as I did, you may need to find the right person willing to assist.

-Joel
I include a better angle on my muffler and pipes, although still not perfect.  Yours should look much like it however. 

[Don Forsyth]

Thanks everyone for the help. I went to my appointment at the State and had three different people looking at this muffler. I told them of the information that I had gotten from the club forum. They told me some people cut the mufflers open and cut out the catalytic converter. This one looks like it came from the factory.
They researched the muffler by the numbers that were on it. By the way, after scrubbing the area were the number is they found a fourth number. So it should read 257-8423. There is also another number (NC1 0035009 42 04) that one of the technicians decided meant, NC no catalytic convert. They called caterpillar with the numbers and still could not come up with a good match. This turned into a 2 hour process. Finally one of the technicians pulled out a scope and looked inside the muffler. Eurica! we have a catalytic converter. They certified this muffler and said I shouldn't have anymore trouble.
I don't know why, but in colorado we have to have and emissions test every year at the turn of a $100 per test.

[Eric Maclean]

Maybe this information ( part numbers ) should be in coach assist section for future reference .
This is not the first time I've heard of this problem
These catalytic mufflers are not that common and are can be easily mistaken as a regular muffler by the uneducated which can lead to these situations and
Frustration during emissions certification.

Eric

[Steve Huber Co-Admin]

Added muffler info under CAT & Allison Manuals in Coach Assist.
Steve