Forum Discussion

mxdad777's avatar
mxdad777
Explorer
Jul 16, 2018

Cummins 8.9 ISL problems

I have a 2005 Holiday Rambler Endeavor with a Cummins 8,9 ISL 400hp with an Allison 6 speed transmission with 57,000 miles on it. I bought it new and have always performed the basic routine maintenance on it. Oil change, filters, coolant flush, etc. I have never had any trouble what so ever with drive train until this past trip. While Going up a small grade I heard a loud pop and lost almost all power. I looked down at the gauges and saw I had zero boost. After pulling off to the side of the road, I removed the inspection cover in the bedroom and saw that the clamp on the turbo hump hose had broke and the hump hose had blown off. These clamps and hoses aren’t stocked at your typical auto parts store and so I was left in areal jamb. After some Mcgyver work I was able to baby it to our destination where I inspected further only to find that 3 out of the 4 hoses were ready to fail. These are hump hoses with expansion rings on them. Two of the hoses only had one expansion ring left and one had two. The fourth hose still had all three rings. Needless to say, I replaced all 4 hoses. So my question is........those of you that have the Cummins 8.9 ISL motor, what have you experienced with this motor that I should be looking at? I’m thinking it might be time to replace all the belts and hoses. Just trying to do some preventative maintenance to avoid being left on the side of the road again. And if you have this motor, I would suggest keeping an eye on these hoses and even carrying a couple of spare clamps and a hose too. I’ve attached a pic of one of the hoses I replaced. This one was missing one expansion ring and you can see how it was swelling where the expansion ring was missing.
So let’s here it, what should I be replacing on a 13 year old motor with 57k on it.
  • I lost a clamp on the CAC hose on our Power Stroke going up an incline while pulling the fifth wheel. It scared the bejesus out of us. The clamp came off with such force it put a dent in the hood of the truck. It's amazing the force these turbo put on the hoses.
  • You coach is a 2005 and the chassis might have been built in 2004. That means that the rubber items are all 14 years old.
    It is better to replace those items at your convenience rather than to try to deal with them during a trip.
  • Yes you are due to replace all belts and hoses. Also look for other rubberized gaskets, bushings, etc that may be cracked or rotted. You should also be replacing tires if you haven't already.
  • Ivylog's avatar
    Ivylog
    Explorer III
    I suggested the new owner of my 04 Dynasty should replace all water hoses as they were original. Turbo hoses still looked new with all clamps tight after 88K miles and 15 years. I replaced the serpentine belt at 10 years and kept the old as a spare as it’s easy to replace.

    I only replaced the serpentine belt on my new 10 years old ride as everything else checked good...it did too but it only took 10 minutes to change.
  • Thanks for the responses. Yes, I am going to replace the serpentine belt and the radiator hoses. I was just wondering if there were any other "problem areas" on this motor that I should be aware of. I was told by a truck driver when I bought the coach that they call the Cummins 8.9 ISL the million mile motor because they can run them a million miles before they have to rebuild them. Weather that is true or not, I don't know. However, it did make me feel good. ;)
  • Double check belt #s. My Alt belt is not the size listed in my OM. From pix on here it looks like my Alt is mounted slightly different. The Alt and AC belts are pretty easy to change otherwise.