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brianreed

Cummins ISL 400hp

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I took delivery of my 2006 Newmar Mountain Aire with a  Cummins 400 ISL engine.  I have not driven a big turbo diesel before other than the single day lesson that I received from the dealer I bought it from.  When I was taking it to my storage place I was going up a slight hill and was at about 55mph when there was a loud pop and I lost most power.  At the top of the hill I was going 30mph and I immediately thought the turbo was not working right.  When I pulled over on the top of the engine at the intake pipe it can separated at the clamp.  Easy fix, but I am thinking this may have been my fault.

Like I said I have not driven a big turbo diesel and I think I was driving like my regular gas engine.  Perhaps I was giving it too much throttle and then backing off as I was hitting the incline.  Could it be that I forced the turbo to spool up then let off too fast and caused some back pressure?  During my lesson the instructor said something about allowing the turbo to spool up and easing the throttle. Like I said an easy fix, but wanted to understand if I was the cause.

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Brian, not your fault, sounds like the clamp failed. Pretty common, if you bring the clamp and bellows to a truck parts store replace both clamps and the bellows. You should immediately notice the replacement clamps are much more robust that what it came with from the factory.

I usually wipe the inside of the rubber bellows and outside of the tube with a rag and with brake cleaner on it, helps it to stay put. 

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In a pinch, you can buy larger hose clamps from a hardware store or other source and gang them together to get the make shift clamp around boost side of the turbo plumbing failure. Even helped a fellow heavy hauler do that one night when he did not want to bothered by a set of Kansas scales on I-70. Bought the clamps at a Kmart, and away we went. 

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Thank you all and you are correct.  It was a bad clamp that someone tried to "repair" rather than replace.  it was just a matter of time before the other one was broken as well.  I could see small cracks on the edges of the bracket.   I went to Cummins and purchased two new stainless clamps and a third as a spare and trashed the old two.  

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