manders
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M923A0 coolant in oil ... it's rebuild time for me!
- Thread starter manders
- Start date
Manders, I found this video for us "visual learners." It's our engine and the fellow states it's from a 5 ton, but not sure if it's an 809 or 900 series truck.
https://www.youtube.com/watch?v=nUns_d4rayY
https://www.youtube.com/watch?v=nUns_d4rayY
He is a member here Acme66. We wont discuss why those engines were being rebuilt though
manders
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Same story for me!
It is pretty simple process.. no different than building a V8 everything is just bigger.
I can send you a take out motor that is known good for what you are gonna spend on a rebuild kit. Only takes 3hrs to have an engine out and another 3 or so to have it back in and running on a 939 series truck. The hardest part is screwing with the hood. everything else is cake.
I can send you a take out motor that is known good for what you are gonna spend on a rebuild kit. Only takes 3hrs to have an engine out and another 3 or so to have it back in and running on a 939 series truck. The hardest part is screwing with the hood. everything else is cake.
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Use a propane torch to lightly heat the pistons instead of freezing the pin, water from condensation can attack the upper wrist pin bushing, BC rods work well in SC engines, they have a much smaller failure rate and with the oil hole moved off center, better oiling.
Trouble shoot it first.....
Trouble shoot it first.....
manders
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More info, some good, some confusing ...
We got the pan dropped and there is nothing but near-microscopic metal particles, i.e., no big chunks of liner material, o-rings, etc., just some small pieces of silicone gasket sealer, which I didn't think too much of, seeing as it was used to join the sections of the oil pan gasket.
A visual inspection of the bottom end didn't show much, and a pressure test didn't provoke a Niagara Falls, so we then started taking apart the top.
With every "layer" we peeled apart, my mechanic helper (remember: he knows more about these engines than I do!
) keeps saying "these parts are brand new!!!". 
We got the heads off and all the pistons look just fine, no apparent cracks on the sleeves, and a "fingernail test" on the liners didn't detect any scoring.
When we lifted the head gasket off, my friend was very surprised when he saw a not-insignificant amount of gasket sealer/maker.
While he is relatively new to the field, he was pretty sure that it was not "normal" to put anything between a metal gasket and the metal block. He called his old boss, buckets more experience, years on-the-job, etc., and he agreed, speculating that maybe somebody thought the block was warped and they figured that putting silly-cone down would make a better seal.
(We also took the oil cooler apart, and found some more of this material trapped in the element, meaning that it circulated pretty much all over the place.)
So now the $64K question is whether this is the root-cause of the underlying problem, or just a symptom of a problem we haven't yet discovered.
While he took a little trip to the local tool supply to get a mechanic's edge so we can see if there is any ***obvious*** warping ... I figured I'd upload some pics and ask for a bit more of the "wisdom of the crowd".
As usual, any and all guidance is greatly appreciated.
MAnders.
We got the pan dropped and there is nothing but near-microscopic metal particles, i.e., no big chunks of liner material, o-rings, etc., just some small pieces of silicone gasket sealer, which I didn't think too much of, seeing as it was used to join the sections of the oil pan gasket.
A visual inspection of the bottom end didn't show much, and a pressure test didn't provoke a Niagara Falls, so we then started taking apart the top.
With every "layer" we peeled apart, my mechanic helper (remember: he knows more about these engines than I do!
) keeps saying "these parts are brand new!!!". We got the heads off and all the pistons look just fine, no apparent cracks on the sleeves, and a "fingernail test" on the liners didn't detect any scoring.
When we lifted the head gasket off, my friend was very surprised when he saw a not-insignificant amount of gasket sealer/maker.
While he is relatively new to the field, he was pretty sure that it was not "normal" to put anything between a metal gasket and the metal block. He called his old boss, buckets more experience, years on-the-job, etc., and he agreed, speculating that maybe somebody thought the block was warped and they figured that putting silly-cone down would make a better seal.
(We also took the oil cooler apart, and found some more of this material trapped in the element, meaning that it circulated pretty much all over the place.)
So now the $64K question is whether this is the root-cause of the underlying problem, or just a symptom of a problem we haven't yet discovered.
While he took a little trip to the local tool supply to get a mechanic's edge so we can see if there is any ***obvious*** warping ... I figured I'd upload some pics and ask for a bit more of the "wisdom of the crowd".
As usual, any and all guidance is greatly appreciated.
MAnders.
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The head gaskets do not seal on the deck. They only seal at the liner, the thin bead around it, BE CAREFUL when cleaning the block so you do not remove/knick the fire ring....and at the coolant grommets...the little white rings that are stuck to the deck, and the oil passage rubbers. See those fiber white rings? One of the things to look for when a head gasket is thought to be a problem, is to look at those grommets AFTER you pull a head. The grommets SHOULD stick to both the head and the deck, the grommet rips in half when the head/gasket is removed. Those were not sealing. No type of sealant should be put anywhere on the head gaskets or surfaces....for that matter on ANY cummins supplied gasket...NO SEALANT, except for puzzle piece pan and gear cover gaskets, only a silicone based adhesive on the joints of the gasket.
Was what was in the oil coolant or plain water? I ask because if the engine has antifreeze in it and the liquid that made the oil milky isn't antifreeze, that means it is water most likely introduced by a loose/missing oil filler cap, dipstick or by contaminated oil. When in doubt, taste the condensation. Sweet = antifreeze, unless it is red antifreeze, then it is bitter. No taste, tastes like oil = water.
Was what was in the oil coolant or plain water? I ask because if the engine has antifreeze in it and the liquid that made the oil milky isn't antifreeze, that means it is water most likely introduced by a loose/missing oil filler cap, dipstick or by contaminated oil. When in doubt, taste the condensation. Sweet = antifreeze, unless it is red antifreeze, then it is bitter. No taste, tastes like oil = water.
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Use a small wire brush to clean the deck around the liners so you don't f-up the fire ring. Clean and dry, that does not mean shiny, stained blocks are normal.
manders
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A little more history of my ownership ...
I purchased this vehicle from the JBLM branch of GovLiq in Fall 2013, and it came from W8BA UTES of the Oregon National Guard. It showed 24035 miles when I bought it, and 24370 now. (Like the proverbial little old lady ... I only drive it to the market once a week ...
)It drove off the lot at JBLM about two miles away to a local mechanic for a quick once-over where it was pronounced road-worthy for the 50 mile drive to my home. About three months later, it developed a coolant leak while out for a leisurely Saturday stroll. I had it towed to another mechanic nearer my home for a complete stem-to-stern review, including changing of all fluids, and it passed with flying colors.
After that, I did short monthly trips for a couple of years, mostly Cub Scout-related local outings, and then work intruded on my hobby and it spent way too much time unattended and gathering dust.
In April of this year I took it to yet another mechanic for yet another stem-to-stern, in preparation for a long drive eastward to Spokane. That's when all the current issue was discovered.
Here is the most-recent mechanics' diagnosis:
I was billed for 9 gallons of oil, which is just about what came out. I didn't see the original waste oil, but here's what I drained this time around:
I dug out my 3x reading glasses and found that 12 grommets showed obvious indications of being ripped, but the remainder were left seated in the block and looked to have a pretty smooth top surface. (I don't know if it's relevant, but the 5/6 head had more ripped grommets than the 1/2 or 3/4 head, which also appear to have less sealant present.)
How prominent should the fire ring be, and is it at the outer edge of the block or closer to the pistons? I ask because I took a soft cloth and cleaned up the least grubby area of the block and could not feel any distinct line.
So ... did someone mistakenly put sealant between the block and the gasket, or am ***I*** mistaken in thinking that this rubbery orangish/reddish stuff is gasket maker/sealant?
The net/net is that I am very eager to understand whether the mere presence of this ... gunk ... floating around the inner-workings of this engine is its' proverbial death sentence, i.e., would swapping in a different engine be cheaper than pulling this block, yanking everything else, then getting everything 'sonic-cleaned, etc.?
Or should I just button everything up, replace all the fluids, spin 'er up and do a "hearty" 30 minute shakedown tour, and then drain the oil and see what surprises I find?
(BTW ... we pulled one bearing to check for scoring and it looks/feels pretty clean, and we'll do the same for the others just to make sure that they didn't suffer too badly as well.)
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There is some srt of sealant on the deck in your pictures, I am color blind, but it looks like it could be copper coat, a spray on copper coating, I think Permatex makes it. Whatever, it shouldn't be there.
The fire ring is on the liner, about half way between the outer edge and the raised part that is the top of the cylinder.
The report says that water was added and it went into the pan, piston debris in the filter media. The mechanic suspects melted liner packing and scored cylinder....that will melt the packing. You pressurized the system and found nothing dripping on the ground. If/when a cylinder scores bad enough to transfer piston material to the liner, there is usually a very noticeable knock that you can short out by shorting the injector and, it creates smoke in the crankcase, this can be seen when the engine is still cool, coming up from the push tube cavity of the failed cylinder, if the engine warms, the smoke is everywhere. As it sits now, troubleshooting is out of the question, you need to look carefully at things.
Since the guy at the shop thinks it is melted liner packing due to scored piston and found pieces parts in the filter, that is an easy inspection since the heads are off. All of the liners should appear to be shiny grey color and you will see honing cross hatch in them. There should be no grooves top to bottom and they will be smooth as glass. A scored cylinder will be rough, have wavy lines top to bottom, they usually are around 2 inches below the ring land area of the piston because the skirt swells and not the crown of the piston, you will need to bar the engine around to get each cylinder at BTC to get a good look at the liner.
What bearing did you inspect? Rod bearings determine the condition of the mains, the lower shell will show no wear, only the upper. The bearings in the 855 are a lead/tin overlay, the coolant attacks the overlay and pits it. SOME pitting is OK for reuse, some not. I think I still have a reuse guideline book around here, let me look.
The fire ring is on the liner, about half way between the outer edge and the raised part that is the top of the cylinder.
The report says that water was added and it went into the pan, piston debris in the filter media. The mechanic suspects melted liner packing and scored cylinder....that will melt the packing. You pressurized the system and found nothing dripping on the ground. If/when a cylinder scores bad enough to transfer piston material to the liner, there is usually a very noticeable knock that you can short out by shorting the injector and, it creates smoke in the crankcase, this can be seen when the engine is still cool, coming up from the push tube cavity of the failed cylinder, if the engine warms, the smoke is everywhere. As it sits now, troubleshooting is out of the question, you need to look carefully at things.
Since the guy at the shop thinks it is melted liner packing due to scored piston and found pieces parts in the filter, that is an easy inspection since the heads are off. All of the liners should appear to be shiny grey color and you will see honing cross hatch in them. There should be no grooves top to bottom and they will be smooth as glass. A scored cylinder will be rough, have wavy lines top to bottom, they usually are around 2 inches below the ring land area of the piston because the skirt swells and not the crown of the piston, you will need to bar the engine around to get each cylinder at BTC to get a good look at the liner.
What bearing did you inspect? Rod bearings determine the condition of the mains, the lower shell will show no wear, only the upper. The bearings in the 855 are a lead/tin overlay, the coolant attacks the overlay and pits it. SOME pitting is OK for reuse, some not. I think I still have a reuse guideline book around here, let me look.
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Look at 3, see in the picture how the liner is wavy and 4 is smooth? It starts just below the ring reversal area.
manders
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Hi Will,
As usual ... great info! I owe you a steak dinner!!!
After you pointed it out, I do feel a slight difference between #3 and #4. I'm gonna do some more digging, I'll let you know what we find.
Thanks.
MAnders.
As usual ... great info! I owe you a steak dinner!!!
After you pointed it out, I do feel a slight difference between #3 and #4. I'm gonna do some more digging, I'll let you know what we find.
Thanks.
MAnders.
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Mr Wagner you are a real gentleman its always nice to have a subject matter expert around to help folks out. I don't have any cummins to pick the brain of I usually use the book. but I do have a few buddys at Cat to pick up tech support when necessary. those of you that share info only received from working at a dealer are a real help to those of us who are stuck in the field working on every thing.
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Thanks, I like to help out, it is nice to see things get fixed and driving again. Talking is easier than typing, PM me and we can connect via phone if you need help. I looked, no failure analysis book for bearings/cylinders, reuse guidelines, musta gave that one to one of the guys when I left. I did find a fracture analysis book tho, I forgot about that one.