Liner O-ring failure

[Truckdriven]

I have a 2017 CM2350 720k mi. that I just purchased and within 2 mo. started losing lots of coolant, turned out to be a failed O-ring on #2 cylinder liner on the exhaust side, Even though all the internals showed very little wear I am doing a full overhaul with all the extra steps this forum teaches. What keeps rolling through my mind is why did the o-ring fail? The abuse history shows the highest coolant temp was 230 for less than 2 minutes so doesn't seem that caused it. If I go all out on a rebuild how can I prevent an early failure putting me back in the same position? It does appear like it had waterless coolant at some point before I had it as the inside of the block looks rusted but is actually a brown film with the texture of dry grease that can be wiped off. Also I had a transmission heat exchanger fail mixing lots of gear oil in the cooling system and I've seen engine oil and coolant mix deteriorate rubber hoses, seals etc but didn't know if gear oil does the same? Also the o-ring looks like it was falling apart long before the trans cooler failure. I will attach pics

         

[tree98]

O-ring probably didn't fail, it's likely you dropped a liner. Make sure you cut and shim your counterbores.

[Mr Hagg]

Interesting for sure. WHen I look at the brass shim here I see either signs of combustion gas or sludge from mixing coolants or something. What does top of pistons look like? What does inside liners look like? You see any heat marks on inside liner? The first few things I look at is friction how was piston and liner looking? Was there heat internal that maybe ECM didnt see? Which would lead to looking at tuning first see what kind of power we trying to make. Look at tops of pistons to see if you see the spray pattern? Was it flashing the liner on top of piston? I wish I could point you into the know but what we have thus far we can only speculate whats going on.. Please post more pictures, top of piston, inside liner, maybe more than one cylinder. Also what do the rest of the liner orings look like?

[Truckdriven]

(06-19-2023 )tree98 Wrote:  O-ring probably didn't fail, it's likely you dropped a liner. Make sure you cut and shim your counterbores.

I had no signs of a dropped liner, no head gasket failure or pressure in the cooling system, when I dropped the pan I didn't even need to pressurize the cooling system to find the leak it was a steady streak running down the outside of the liner, see pic.

[Rawze]

First and foremost, that o-ring will not normally leak unless the liner started dancing in the block. The brass shims will always hold back the coolant unless someone installed the liner with debris on its brass shim, or the liner was dancing in the block. The o-ring is simply a back-up to this.

I.E.> The liner o-ring is a 'back-up' o-ring, and not the primary means that keeps the coolant held back in that area of the engine.

The pictures show that o-ring is deteriorated heavily due to rot alone (oil or some other contaminant in coolant at one point) so badly, that if it were the only thing holding coolant back, it would have failed a long ago. The fact it started letting coolant past it at this point, is the liner moving around .. not the o-ring itself.

The mid-stop in the photo shows that it is also heavily fretted on the thrust side, pointing to this as well.

So all things in the photos so far heavily points towards a liner starting to dance.

Any signs of a head gasket failure too?

How about micro-etching in the bottom side of the head where that liner sat? head is likely fretted too. - This would give it away, even if there were no other visible signs.
an example on how to spot this: http://rawze.com/forums/showthread.php?t...48#pid7648

Also,.. is this the same engine that had the unknown quality ecm program that you sent me back in march to review???.

That file was good ... it had gotten straightened out by the time you purchased the truck ... but what about prior to this?. What about the last owner, and its older history? ...

I just so happen to have the bad delete that used to be in that truck a long time ago. It was back in oct-2021.. before you purchased that truck.

- Here is what was in that bad delete program that eventually got straightened out, here it is at a quick glance...

** The injection timing was ridiculously too high and extremely harmful to the engine. Could cause liner dancing and/or overheating of the cylinders. Can also cause a cracked piston

** turbo was programmed to absolutely destroy that engine with more than 38+ lbs of boost. A CM2350 without EGR can only handle about 33,34 lbs boost before it becomes VERY harmful. - Combine this with the fact that it was set at 2050trq/600HP.. and this alone would have made something eventually come apart in it... + destroy turbochargers due to over-spooling.

** Amonia clamping and other aux. emissions systems were not switched off properly, so this would have screwed with it in negative ways too.

** The fuel pressure tables were jacked way up, making it really hard on the pump + making the cylinders too volatile. This is harmful as well.


-== There are also other issues in the program. Those were just the highlights that might have contributed towards the most likely progressive damage that it suffered in its past. this all before you purchased it. it did have 580,000 miles on the odo when the program was finally straightened out correctly the first time, and who knows how long it ran with that bad delete in it.


============================
This truck is also a decent example of why I always try to warn people about buying into a half million miles old truck with a square nose, combined with big HP, and geared wrong for hauling any freight ... it have been lugged to death its whole life below 1500rpm's, can hardly get out of its own way bobtail, nonetheless can climb a decent hill fully loaded with those garbage tall rear ends.

It being a 600/2050 set engine in a truck with tall 3.36 rears + driven hard (the bad delete file also gives that away too thru the low fuel mileage it had at that time) ... .. I would say it lived a longer than expected enough life if it made it past 750k.

(just for education for other people reading this )...
-= Thus is what a person gets when they buy into a used square-nose truck with 500+k miles + power set to 600HP/2050 .. It tortured and lugged to death because it is geared too tall, and all the rest of the abuse that it had likely suffered to begin with.

.. so 750k on the odo before it gave up the goat? .. i would say that in this case, you got lucky. It should have failed (predicatively) before it got to 650k... yet you got an extra 100k miles use out of it above this.

The question now is ... Did you know already that it was on borrowed time, and was this notion a part of your business plan?. - Because it should have been from the day of purchase.

Can it be made to NOT do this again?... sure, with building it to the specs talked about on the forum here.. 100% to the letter, no shortcuts
ref: http://rawze.com/forums/showthread.php?t...6#pid70606

.. + get rid of those garbage rear ends and put a decent set of 3.90's in it (maybe even 4.11's, as it is a square nose and should not be driven more than 70+ mph .. ever ... any ways) like it belongs. Set the the power to 575/1820trq. This is plenty for a truck with a set of decent 3.90's in it to climb about any hill while lasting that next million+ miles.

[Truckdriven]

Ok I'll try to answer all your questions,
Did I consider and plan for an overhaul this soon? Yes I consider buying any used truck a high risk of needing to do an overhaul very soon, especially in this case and will not be cutting any corners to build it right. Since I am not in the position to buy new trucks this is a risk I took figuring not all is lost if I need to overhaul it since I can build it properly myself and actually have a reliable engine then

And yes this is the same truck I sent the unknown file from back in march, interesting to learn what the history was before

I looked at things closer and Rawze seems to be correct about the dropped liner, but there were no signs of a blown head gasket. I looked closer at the thrust side on the Block and there is definitely fretting there, I'm glad to know that the O-ring is only a backup seal therefore if I counterbore it correctly I won't have to tear it down again for a deteriorated o-ring. I looked at the head and didn't see any steps worn in the head, but when I peeled the gasket off there was a space on each cylinder where the gasket wasn't stuck fast as if it was working at blowing through the seal?? Also while looking at the head closer I noticed every cylinder has cracks in the head between the valves, some have cracks between every valve on the cylinder, a new (not reman) OEM head will be here this week.

According to Rawze when the file was checked it was set at 565/1850 when the file was fixed back in oct.2021

I do not know the condition of the other o-rings yet as I want to measure liner height yet before I take them out, I will post more pics of cylinder walls, piston tops before long.

I am not arguing that it it should have better gearing but I always questioned what the difference is, if I stay down shifted to keep rpms up?? is that much different than having 3.90's or 4.11's and being in a higher gear?

[Truckdriven]

Here are pics of the piston tops

[Truckdriven]

Here are the sleeves

[Truckdriven]

And number 6