ISM Cracked exhaust pictures

[a k]

Is this OK to do?

[SX_RVing]

a k,

Nice job...... Looks all too familiar

[Chickadee]

a k: Thanks for the outstanding description and pics re: install of the turbo to exhaust flex fix for this problem. We drive an 08, 4502 EX (500 Cummins) and though I've tried checking this, I also had Randy at Nappanee check and so far all looks o.k......BUT, because of your fabulous pics and description, even THIS inept mechanic might tackle such a change out if needed.

Thanks again. Steve

[a k]

It's not IF it cracks, it's WHEN.

There is no give between the Turbo Charger and the Clamp on the back of the motor.

Heat up, cool off, heat up, cool off=expansion and contraction.

They put the flex originally on the end of the exhaust pipe when it shoud of been after the Turbo to begin with. The only thing holding the pipe on after it cracks all the way around is the 5" muffler clamp in the back.As you can see , mine was hanging on by a thread. Again, if it breaks away, the exhaust will shoot straight at the back of the closet. If you don't think your exhaust is hot, look at this picture and tell me what caused this.

A K

P S: can anybody take a poll to see how manys been replaced and at what milage?
Found it strange when calling for part, first thing they asked how many miles on it.

["007"]

Thanks ak will post in Quick Tips. They should have sent you a new mud flap.

[a k]

Nah, it's my fault. Have a hydra-lift welded on back and had moved the mud flap rearward. If you go above a certain speed the wind raises it up and the exhaust blows down on it. I moved it up , but damage done.

["007"]

Nice job ak
Looking at your last picture it looks like a battery or Gen ground cable connection gone bad, if it is I would place new bolt and nut and clean up frame connection may save some headaches later.

[a k]

I saw it, that's what two weeks on the Fla coast does to metal

[Doc Mark]

Mine failed at 17,000

Mark

Quote:

Originally Posted by a k It's not IF it cracks, it's WHEN. There is no give between the Turbo Charger and the Clamp on the back of the motor. Heat up, cool off, heat up, cool off=expansion and contraction. They put the flex originally on the end of the exhaust pipe when it shoud of been after the Turbo to begin with. The only thing holding the pipe on after it cracks all the way around is the 5" muffler clamp in the back.As you can see , mine was hanging on by a thread. Again, if it breaks away, the exhaust will shoot straight at the back of the closet. If you don't think your exhaust is hot, look at this picture and tell me what caused this. A K P S: can anybody take a poll to see how manys been replaced and at what milage? Found it strange when calling for part, first thing they asked how many miles on it.

[SX_RVing]

I noticed mine at about 29,000 miles

[a k]

I think if it isn't broke you could sawzall it and add the flex to the original pipe.

Mine was 23,000 miles

[94-Newmar]

I guess this design problem hasn't been resolved since at least 1994

Here is a pic of my 1994 Newmar Kountry Star, Spartan/Cummins 8.3/300hp exhaust setup which I just had to replace. This has a PAC brake further to the right which you can barely see. Next time it breaks I'll be replacing the inline PAC brake with a turbo pedestal mounted brake to avoid that silly little length of tubing between them.

[Chickadee]

a.k.:

We run an 08 model, 4502 Ex, with the ISM 500 (Date of Manuf. 05/07/2007) and consequently I've added this to my "worry about" list ever since I first picked up on discussions about it last year. Even had Randy, the Cummins rep. at Nappanee check for cracked fitting when we were at Newmar last June. He didn't comment much about it other than to assure me it was o.k.

Since this appears to be a matter of "when" it cracks, and not "if" it cracks, have you been able to determine a reason Cummins doesn't undertake a change out "campaign" (recall) for this problem, particularly since, as 94-Newmar mentioned in reply post #12 (above), it may have been a problem since 1994?

I agree about the "poll" you suggested. How can we proceed?

Steve

[RVDude]

Just to clarify a few points to keep us all on the same page.

1) The cracking exhaust pipe is NOT a Cummins issue, it is a coach builder (i,.e. Newmar) induced issue in that the coach builders do not properly locate (or move) the U-Clamp holding that pipe to the chassis and thus induces the torque to crack it. It is tangentially a Spartan chassis issue in that the chassis builder (Spartan) supplies the exhaust and (allegedly) correctly locates that clamp prior to shipping, however, when the coach is added on top of the chassis the clamp is often "adjusted" by the coach builder.

2) Randy at Newmar is a Newmar employee who happens to be exceedingly well versed and highly trained in Spartan chassis repair. He's one of the "A" team at Newmar. Really a super guy....

3) It really isn't a "when" issue, it truly is an "if." "If" the clamping location was altered by the coach builder or somehow was not originally performed correctly at Spartan then you "might" get a crack. This issue does not have the infamous ISM/K2 fan drive issue characteristics.

4) The following info may have changed or still be in flux, but, my last info of early summer 2009 is that after figuring out the cause of the cracking, the "fix" is to ensure the U-clamp is properly located - some xx distance from some fixed point - and use the solid exhaust tube. Randy as I understand it, was a principal in figuring out this cause and fix. The flex pipe solution, again as I understood it in early summer 2009, was a temporary fix until they found the real cause. Personally, I am a fan of the flex pipe solution.

5) My understanding is this issue is limited to ISM powered K2's delivered to all coach builders (not just Newmar) - again, it is the coach builders who are moving or playing with that clamping location to fit the coach.

6) Again, to be fair, my understanding is that 94-newmar's experience is an anomaly and though similar in perhaps cause and effect (same cracking) is not an indication of a long pending issue on multiple chassis/engine configurations.

Just an FYI, you can even fix this problem with hose clamps and aluminum foil. (The point being it's really not that severe) My repair lasted some 2,000 heavy mountain miles before I got it "properly" fixed and it still had not leaked a poof of soot when they pulled it.