Forum Discussion

elhajj33's avatar
elhajj33
Explorer
Feb 28, 2017

$300 Exhaust Diffuser or Aftermarket Tip?

The Exhaust tip on my DP is rusted- in fact, the whole exhaust extension is rusted. I got the exhaust extension from fleetwood and am deep into the replacement work (the old pipe broke inside the muffler collar and getting that out is going to be fun since it's corroded. Any suggestions there would be great!)


As for the diffuser, the exhaust diffuser from freightliner is $300. It seems to me I should be able to use any 4" exhaust tip as long as it turns down after the rear bumper. I'm quite certain I haven't seen my exhaust diffuser on any other cummins ISC based MH so I doubt it's specific to my engine.

Any thoughts?
Class A
  • 11178adm's avatar
    11178adm
    Explorer
    May 08, 2017
    I see in your profile that this is a 2009 MH if it is and this unit has a diesel particulate filter and requires a regen the defuser is there to mix fresh air with the exhaust to lower the outlet temperature during a parked regen, it is a safety item and it is not recommended to remove it
  • elhajj33's avatar
    elhajj33
    Explorer
    May 08, 2017
    I managed to get it off with PB Blaster! Took a can or so, but was able to get the job done! I also used an aftermarket TIP if found on amazon. $75 did the trick on that. It was a pretty easy job after finding the parts!
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Feb 28, 2017
    If you can get into the collar with a dremel or electric hack saw, cut some slices in the old pipe in several spots so you can pry the old pipe away from the collar.

    I wouldn't worry too much about a diffuser on yours. Just get something that points it away from your toad. My coach has DEF and runs much hotter, so a diffuser, spaced away from the tip is more important.

    If you need the diffuser, buy a 4" or 5" chrome tip with a bend and cut a section out of it length wise, so that it'll bend and clamp around your 3" tip
  • Ivylog's avatar
    Ivylog
    Explorer III
    Feb 28, 2017
    I would use a tip that does not turn it down as much as all the diffuser does is spread the heat out so when it regenerates you hopefully to not catch the grass on fire or burn the asphalt. Cutting through the old piece and then bending it up and twisting it out is where you'll end up if it's rusted so much as to rust off. Good luck.
  • elhajj33's avatar
    elhajj33
    Explorer
    Feb 28, 2017
    Twomed wrote:


    Lots of penetrating oil... saw a slot, twist it out.

    Hard work but remember you are saving $120 an hour. :) :)


    i wonder how long surgery on my shredded hands will cost per hour :D I just hit it with PBBlaster and will do so again throughout the next day or so.

    Kidding aside, i really don't want to do any sawing (i'm pretty sure the folks in the RV park won't take too kindly to that!)

    Thanks for exhaust parts. I'll see what i find there.
  • Twomed's avatar
    Twomed
    Explorer
    Feb 28, 2017
    Exhaust stuff

    Lots of penetrating oil... saw a slot, twist it out.

    Hard work but remember you are saving $120 an hour. :) :)

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