ISX 650 cummins - Printable Version

+- Newell Gurus (https://newellgurus.com)
+-- Forum: General and or Other Stuff (https://newellgurus.com/forumdisplay.php?fid=16)
+--- Forum: Discussion about what to consider on buying a used Newell (https://newellgurus.com/forumdisplay.php?fid=80)
+--- Thread: ISX 650 cummins (/showthread.php?tid=8766)

---

ISX 650 cummins - Figs - 11-25-2025

I’m looking at a 2012 with ISX 650 Cummins. I’m hesitant because of the 650. Your thoughts?? Thank you

---

RE: ISX 650 cummins - encantotom - 11-26-2025

i can only speak to a 2013 isx15 rated at 500hp on a cascadia super c weighing all in at 38k lbs. it has 45k miles on it, with a eaton 13 speed ultrashift. pulls like a freight train. doesnt slow down going up hills. got 8mpg on a 9k mile trip this summer. the 650hp i am sure has different injectors,, maybe cam and not sure what else.

i have several buddies who manage fleet truck repair centers and they love the isx. i had zero issues on my last trip.

compared to the series 60 in my 53k lb newell, the isx pulls stronger, but the newell weighs alot more.

my two cents worth

tom

---

RE: ISX 650 cummins - Richard - 11-26-2025

Has the head been replaced

This is MY opinion. If the head has been replaced I would be comfortable. If has not, I would subtract 50k from the price, buy the coach, and immediately have the head work done.

---

RE: ISX 650 cummins - Figs - 11-26-2025

Thank you for the responses!!

---

RE: ISX 650 cummins - Little - 12-03-2025

You can take the coach to a Cummins approved shop. They can scan the ecm for anything and everything since the engine was installed. Cummins had issues with the 650. I never worked on one but did see more than one that self destructed.
Cummins never really dealt with this as far as I know, but they did warranty some. Lots of my peers have ideas as to the reason, but as Richard said once the head was done the problems appear to be gone.

---