Yet another, cm2350 overheating

[Vengeance]

Hello everyone, thanks for letting me be a part of the group! Over the years this has become the first place I look when troubleshooting.

First off I've been driving for a little over 12 years. After leasing several trucks off and on, I finally developeded that brain injury some of us are familiar with, or possibly some undiagnosed metal health issue, and decided to just buy my own truck last summer. I actually love my truck, took forever to find anything close to what I wanted, felt like I paid too much, then 2022 and it's worth double what I paid, go figure.

I do all the work I can physically do myself. I'm self/internet taught, so that means Cummins and English don't always translate well.

This has turned into a long term nightmare, I've read so many posts all over the internet that they all blur together.

I'll try to be as precise as I can, I have talked to mechanics at Cummins, Kenworth, and everywhere else I run into someone that might have an idea. I won't let anyone throw parts at it, or diagnose me into bankruptcy.

Forgive me, this will be VERY long.

Truck is a 2015 Kenworth W900, Cummins ISX 15 X101 CM2350, purchased with 633125 miles, currently has 794689 miles and 26553 hours. Hasn't given me any more issues than any other used truck, not deleted, not modified (my thanks to Rawze for his post on the dangers of modifying these engines)

A few months ago driving in Utah, stiff headwind long grades, outside temp around 75, the CEL came on, noticed coolant temperature was 230, oil 245. Coolant never would come down much past 200-210. Oil 220-245. Even at idle coolant was 205-210 with the fan off and on constantly. And yes it blows the right direction, hard enough to blow my hat off if I get too close. Temps verified with my temperature gun.

Did some research, got it home to Alabama, decided it was time to do the whole EGR tune up bit while I was there, clean the DPF etc. I had some cash to spare, had been saving up for a clutch I knew was coming....

Replaced: coolant thermostat, coolant temperature sensor, oil thermostat.

Cleaned out the half plugged EGR cooler. (BTW Rawze, Amazon feeding tube cleaners, which are 3 foot long wire brushes are the perfect size for this)

Cleaned and Checked out the oil cooler while I was there, don't have any oil/coolant cross contamination so not concerned.

Turbo had some soot, but not coated, caked, or even completely covering the vanes. Spun quietly and smoothly.

Put it all back together, next run hauling ass up I-29 in Iowa, outside temp is 101, coolant around 190 oil 225. Fan comes on occasionally. Everything just as it should be.

That lasted a week. Then right back to overheating. I have no idea if something I did fixed it or if it was just coincidence. I really haven't wanted to take everything off that half of the engine again, mostly because it doesn't make sense. It's a coolant temperature issue not an oil temperature issue, right?

Headed up to Billings MT, middle of the night, nice and cool out, I'm west of Broadus MT climbing the hill, and it derates, too hot again. Few miles down the road the clutch I once had the money saved up for gives out. So I take it in to MotorPower in Billings on a Saturday, and they start on it that Monday. I just can't do the clutch myself, without a proper shop and equipment. Needed a new rear seal too. I do actually recommend this place, they have reasonable rates for a dealership and try to keep the costs down. They couldn't see any obvious reason for it to be running hot, and even reasonable dealership labor is expensive. And without an obvious cause I knew it would be a game of throw-a-part. IF I HAD ONLY KNOWN THEN WHAT I KNOW NOW!

So trucks gotta run, bills have to be paid by this point. I'm out the door with my nice new clutch.

I know someone is gonna give me a hard time about it, but I was getting by with running the fan, and driving it a little easier. Problem managed while I try to figure out the cause and solution. I agree that band-aid fixes are bad, but needs must. I made it 135 miles, then boom top radiator hose blew, middle of nowhere between WY and NE. Those damn fancy metal rings they use to make them stronger rubbed right thru it. So nice guy at O'Reillys runs out to me with 4 gallons of coolant and the second most expensive hose I've ever bought. While I'm waiting and since the coolant is already drained enough, I replaced the thermostat again, I had already picked one up thinking maybe I just got a bad one. Problem fixed, but still overheating.

So I'm driving and thinking, and I decide to stop and replace the coolant filter. I pull the old one off, and I find two small strips of plastic in the top of the filter. I wish I had taken a picture, but the closest description I can give is like someone squirted two half inch lines of Elmer's glue out and let them dry, then peeled them up. So right then I pulled the dremel out and cut the old filter open. Nothing.

Made it maybe another 75 miles and I hear a belt squeal. Opened the hood and I thought the whole damn engine had blown apart. Oil everywhere, dripping off everything, so I thought that's it! In frame time! A little bit later, and with calmer nerves I start looking, and I notice the rubber plug covering where you bar the engine over is missing. That little trickle of oil plus the fan made a huge mess. Then I notice the coolant is low, I had just topped it off when I changed the filter. I look more and I see coolant bubbling from the exhaust pipe on the EGR cooler intake. Then I started putting it together, leaking EGR cooler, increased pressure in the cooling system caused a hose to blow, and explains the overheating!

So I found a reasonable tow company, yet another I'll recommend, Little Tornado, somewhere around Ogalla NE. Got the truck towed to MHC in Cheyenne. Three days later I've got a new EGR cooler, and I bobtail back to where I left my loaded trailer in NE. I'm thinking, Finally! Fixed! And for the first time that extended warranty covered something, or at least half of something.

Get hooked up and rolling, and guess what, damn thing is still overheating, really I should say running hot, it hasn't reached a point where it's hot like pull over now. But right on the edge of that.

So at this point I'm thinking it's got to be coolant flow or heat exchange. I remember reading about some of these engines having plastic for parts of the water pump. So stop by fleetpride and grab a new water pump. By now I'm becoming more willing to throw parts at it, with at least some educated guessing. A few hours in the dirt at the truck stop and I've replaced the water pump, twice because the new O-ring wouldn't seal. Still not fixed.


On top of that another of its long term issues, random off and on again low fuel rail pressure, is acting up. Never been a huge thing, once a month or maybe for several days in a row every few months the truck would just die after stopping when it's been running hard. Or maybe at the bottom of a long hill it would hesitate, like it was starved of fuel. But not enough to give that dreaded 559 code or whatever it is. Had the fuel pump head done right after I got it, so those crappy ceramic things are gone!

Well to end this short novel, I start thinking low fuel rail pressure, Cummins talks about leaking injectors in the troubleshooting steps. So why not, I order an injector. Don't really have the money to get all the stuff to do it all by the book, so I'll swap it in and out and see is one injector is bad. While I'm there I found a good price on new fuel ports so I'll replace all of them, just to feel like I'm following the book a little.

Anyone ever have the fun of working on an engine after someone less capable, or knowledgeable worked on it before? So I end up replacing 4 injectors because some moron had already over torqued the terminals on most of them, and before I even started getting them snug, they snap. So much for the full core charge!

Still not fixed. Still runs hot. Makes no sense, no signs of a head gasket problem. Coolant is already too hot before the oil thermostat opens, once that happens it's down hill from there.

I am going to try the radiator flush routine when I get home, but fact that one day it was fine, next day it was running hot, then the week it was fine, then hit ever since does not leave Mr with much confidence. I've also pressure washed the radiator back to front. I remember reading a post from Rawze saying in general there should be like a 20°- 40° temperature difference between the coolant and oil.

Top it all off, it just made it to the top of the steep grade on I-90 in Montana without a hard derate. But this is the first actual cool almost cold weather I've been in since it started. 45° outside at the top of the mountain, and at idle the coolant is almost 210, oil 220.

The last few months with down time, parts, related and unrelated repairs, I probably owe my carrier close to $30k, and I've gone from money in the bank to struggling to buy groceries to take with me in the truck. Partly my fialt for not wanting to pay the crap ton of money on labor and random parts early on, but at this point, it's either fix it and file bankruptcy, or fix it and refinance the truck to get back on my feet. I only financed for 3 years in the first place, it's paid off in less than 2. My plan was to trade in for a new truck, but even finding a new truck for sale right now it would cost more than a small fleet a couple of years ago.

Might be the longest post I've seen on here. But I'm hoping by telling the whole story something in it might give a hint or that small bit of info that points to a solution.

Any more info, temperature readings, just ask. I have my temperature gun, and a copy of insite that works when it wants to, usually can't really run tests well, or monitor anything more than a quick reading. I think it has some compatiblity issues with the Drewlinq interface I have. Worked fine with DDDS, but not great with insite.

Thanks for your time! And in advance for the help!