830k miles ISX cm2350 on borrowed time?

engine_900 · May 27, 2025

Yup, speed capped at 64mph and can't be pushed over 1400rpm at 8-low shift which bothered me sometimes. Programmed by KW with password can't even been cleared by Cummins Inline thus can only be undone by KW dealers. Visited them once in 2022 and they did nothing other than dumping data and would call me when they could do that which never happened, so I never bothered to try again since I ran I-5 and Rocky mountains mostly and I can live with that. On the other hand it does help keeping the engine less stressful.

201 said: ↑

Really, 1 gal for 17K almost sounds like something wrong the other way. Heck, I remember that old KWhopper with the SC350, we added 2 gallons of oil at every fuel stop! Matter of fact, I drove plenty of trucks with old Detroits where the boss said, "and take some oil with you",,
Click to expand...

engine_900 · May 27, 2025

D.Tibbitt said: ↑

Is this truck demandated ? If it still has an active egr cooler these can leak and cause sludge. They are known to spring leaks after draining and refilling coolant if not refilled back under vacuum. The excess air in the system that gets trapped can cause the cooler to leak. Maybe could be a good place to start. That a.ount of coolant usage is about what a egr cooler leak would use. Can pop the clamp off the back side of the cooler and check if it's wet with sludge. Will also be in your crossover tube as well
Click to expand...

Kinda yes to all. Will check that for sure!

Brandonpdx · Jun 2, 2025

Oil consumption sounds normal but the coolant consumption doesn’t. something’s up there I bet. Turbo, EGR cooler, head gasket…I drove a T800 company truck with a Cummins a decade ago that had a lot of disappearing coolant and it turned out to be the turbo. (thought for sure it would have been the EGR cooler…)

the powdered dishwasher detergent is what you want to use, not liquid dish soap to clean a cooling system.

RunningAces · Jun 8, 2025

engine_900 said: ↑

The oil cooler was replaced in January 2025 after oil buildup in coolant reservoir since Nov/Dec 2024.

Black oil sludge kept building after the repair. I thought the repair shop didn't flush completely since they spend like 8 hrs to finish the oil cooler repair and I had the truck back at end of the day while they were still flushing the engine. So the oil could still reside everywhere in the coolant system.

At end of April I did another 13 hrs flush myself... 6 cycles with Dawn and 4 cycles with clean water. From Saturday till Sunday afternoon and the truck had to leave for a delivery job.

Right now it still produces some oil sludge, not black anymore but white/greyish color. I'm not sure whether it's from active oil leakage somewhere else like compressor/head or residual sludge from heater core/radiator. I also spotted some whitish oil sludge at oil filler tube first time this week, but nothing on dipstick yet.

Coolant consumption has been 1 gal/4days since Feb/March, could be coming out of oily coolant pipes eating by oil sludge still in coolant system? Pending full replacement if/after the oil sludge issue could be fully repaired.

The engine treats me well since I bought it at 595k miles in 2021. Still burning 'only' 1gal oil for 17k miles range and 6.5mpg for a 45k load. Oil cooler is the only engine part that has been repaired so far. I have been keeping turbo working below 25psi all the time to prolong engine life as long as I can.
.
It seems to be a bitter time to do inframe considering the rate, the economy trend and used truck price. I'm also thinking of buying another used truck vs. swap another ISX/CAT engine, since my truck frame is not perfect and has some rust I cleaned/repainted in October 2022 and due again this year before winter. Truck frame is a 2016 T680. Its my first truck so abit sad to let it go, but when coming to money/business decision its a different story.

Any comments are greatly appreciated!
Click to expand...

I just posted a thread about oil in my coolant reservoir and I also have a cm2350. Did it looks like this on yours?

engine_900 · Jun 12, 2025

RunningAces said: ↑

I just posted a thread about oil in my coolant reservoir and I also have a cm2350. Did it looks like this on yours?
Click to expand...

Yours looks much better than mine, it is like mine coolant tank in early December 2024. Right now my coolant tank is greyish milky again....keep running until coolant consumption surge to 1 gallon/day or oil becomes milky.

Log in or Sign up

Forums

Find Trucking Jobs

830k miles ISX cm2350 on borrowed time?

engine_900 Bobtail Member

Trucking Jobs in 30 seconds

Wait, employers can't reach you!

engine_900 Bobtail Member

Brandonpdx Road Train Member

RunningAces Road Train Member

Attached Files:

20250605_052456.jpg

engine_900 Bobtail Member

Trucking Jobs in 30 seconds

Wait, employers can't reach you!

Log in or Sign up

Useful Searches

Find Trucking Jobs

830k miles ISX cm2350 on borrowed time?

engine_900 Bobtail Member

Wait, employers can't reach you!

engine_900 Bobtail Member

Brandonpdx Road Train Member

RunningAces Road Train Member

Attached Files:

20250605_052456.jpg

engine_900 Bobtail Member

Wait, employers can't reach you!