Cat 3116 lost oil and started knocking

radbad

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Hi guys - I'm trying to figure out the best resolution to a catastrophic failure I recently had on my M1079. The truck is an A0 with a mechanical CAT 3116.


While driving down the highway, the engine had a vibration-fatigue failure on an oil line to the governor. This caused the engine to lose all oil in a hurry, after which it began knocking. We shut it down as soon as we saw the engine oil pressure light come on, but the knock started before we got stopped.


We received advice from a CAT service tech that "the damage is likely already done, but maybe the noise is from the governor and will go away in a few seconds with oil", so we replaced the broken line and filled it up with oil. We ran it for about 10 seconds at idle and were about to shut it down when it clunked to a stop. Currently the truck is parked outside a shop about 200 miles from my home awaiting a decision on how to move forward.


We had the shop take a look, and they advised that the engine isn't fully seized (which means it can be rotated and the trans can be disconnected without having to pull it out with the engine). They gave a quote of $3250-$4250 to swap the engine with one we provide (Used cost is about $3000 with a 6-month warranty from someone in the LMTV community).


I don't know the best way to proceed here... lots of options. Let me know if you have any thoughts/guidance!


- Will an in-frame rebuild kit revive this engine after the seize? Should we drop the pan and pull the head to see if any obvious catastrophic damage has occurred? What should we look for?

- Is our best bet to just do the shop-quoted swap at 6-7K all-in?
- We're considering bringing it back home to work on it, but are currently quoted $2k to tow it the 200 miles home. Any recommendations on transport?

- Nobody seems to love the 3116 engine - should we change to something else (3126, C7, DT466, Cummins 6.7 ISB)? Plumbing for fuel/exhaust/cooling, electrical considerations, engine mounts, and transmission-fitment are all complications that make this seem like a long project.
- Our last option is to abandon the project and sell it as-is, but I'd rather not go this route. If we have to, what's an engine-less M1079 with a fully remodeled cab worth?


Thanks in advance!
Brian
 

frank8003

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Help everybody else too. Exactly which oil line failed?
I ask only as engines are not supposed to fail due to one oil line.
Lots and lots of really good questions her will be answered.
 

coachgeo

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Help everybody else too. Exactly which oil line failed?
I ask only as engines are not supposed to fail due to one oil line.
Lots and lots of really good questions her will be answered.
there is a small line..... squared U shape; on its side, that attaches to the Governor. This is the one. Not first time this has happened. Fellow reported similar recent and others have reported it before too.

Recent thread on this topic also
 

NDT

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Many stories on here of failed LMTV engines due to broken oil lines, which are caused by the way by vibration caused by driveshaft spline wear. If you are not a DIYer it’s a matter of doing the math. Very likely the crank is scored up already, which makes an inframe not an option.
 

tennmogger

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Looking at just the numbers, if your cost to buy this truck initially, plus the new engine, plus the labor (which will probably go up) is much more than the cost of another running truck, then buying another truck wins the contest. Then part out the failed one to recover some bucks. Being so far away from the truck sure makes the decision tougher.

I had a 3116 engine lose oil too (oil pressure sensor blew out, grounded itself, and engine diagnostics never knew it). It burned up the main bearings, the turbo, and other assorted internals, but didn't lock up, so might not have been as bad as yours. It does not take long to trash an engine.

I am replacing the engine. But in my case the truck is home, a replacement engine was available locally (no shipping), and no labor involved except mine.

Tough decision. Good luck.
 

SausageGuy

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Tow price seems way off of reasonable. To bring my 1084 from Louisiana to KC was 2000$ including semi tow trucks at each end to load and unload it.
I would buy another truck to part out like tenmogger said and be money ahead if you have the ability.
 

radbad

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Geopen - you are correct in identifying the oil line that broke.

NDT - What is the recommended correction for the driveshaft vibration? I've heard people balance them, but if the issue is spline wear, that doesn't seem sufficient.

SausageGuy - Any recommendations on how to find a reasonably priced transport option?

Does anyone live in the UT/NV area and have the ability to help flat tow me home?
 

NDT

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If your driveshafts don’t pass the “hinge test” which is basically zero discernible movement up and down at the spline, your best option is to bring them to a drivetrain specialist and have them replace worn components.
 

Reworked LMTV

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We need a special sticky note area "Things to check on your 3116"
there is a small line..... squared U shape; on its side, that attaches to the Governor. This is the one. Not first time this has happened. Fellow reported similar recent and others have reported it before too.

Recent thread on this topic also
 
209
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Fallon, NV
Last year I had my LMTV trucked from Maryland to Colorado for about $3k by United States of Freight, the load was shared with another large vehicle (armored car). They're an advertiser on this forum.
As for drive shafts, I had both of mine rebuilt for about $1200 earlier this year based on suspicion and noises. Both slip joints were badly worn and replaced, along with the U-joints.
When I bought the truck about three years ago, it was already missing the alternator bolts and the bolts on the mount between the air pump and power steering pump.
After having the drive shafts rebuilt, drove the truck pulling a smaller truck (the Zombie Truck in my signature) from Colorado Springs to western Nevada with nary a problem.
No leaks or cracks, knock on wood, smooth running.
There's a place in Fruitland, ID that has a scrapped LMTV with near-new motor - Idaho Motor Pool. I cannot speak to their prices though...
Bum luck with the engine, hope you get it worked out!
 

coachgeo

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....still can't find that post with a shot of a replacement line where Parker? store put a loop in the metal line to reduce vibration issues. Anyone remember that thread?
Found it...... was on facebook. Had remembered wrong. Was not a loop.... just an extra whoopty do to make it little longer to help reduce vibrations and put the line at a straighter shot with the fittings. Biggest issue seems to be assembly. If they two fittings (one on governor and one on block) where oriented during assembly in a path directly in line with the tube.... it would relieve a lot of the issue.

https://www.facebook.com/groups/1607576859556624/permalink/1975366566110983/

Here is quote of it and borrowed picture

facebook Sean Ornduff said:
Had an interesting event the other day. I was in the process of registering my 1078 and they require me to have it weighed. So I am cruising down the local highway goi g to my nearest scales and the lights come on the dash oil and STOP. The oil pressure gauge is bottomed out. I pull off as fast as possible into a safe spot. Shut down the engine and jump out of the truck and their is oil everywhere. Tilt the cab and start inspecting for the culprit. My first hunch was an oil line had blown and I was looking for a fair size line because of the amount of oil. The culprit was a 1/4” hard line coming from the engine block into the injector pump (govern). Fractured right at the nut. Odd in my mind. Called one of my employees for a ride and some tools. Took it back to the shop, tig brazed it with siliconized bronze and headed back to the truck with 8 gallons of oil (not knowing how much I coated the highway with) reinstalled the line and put in 6 gallons of oil. I have my theory of why the line failed. It is made from a hardened steel that does not give and will fracture before it flexes. The fitting on the block is cocked just a tad past 3 o’clock and the fitting on the pump is just a bit off as well. The mounting surface is flat making it a wide point of mounting against an oring. I searched on the web and some tech manuals for a replacement and finally decided it would be faster to just machine up a replacement the way I think it should be to allow some flex with the minor misalignment and the vibration of the engine. New stainless line. DIY.
Has anyone else ever encountered this?
Sorry for the long winded story.

Their are two lines that I believe are problems. One is up a little higher coming off the injector pump and has a non standard fitting that uses an oring on a flat surface for mating. The other is down lower, runs behind the injector pump and is a standard -AN hose. I believe it was either a -3an or -5an. Would need to look at mine to recall. The lower AN line you can easily replace with a flexible hose from summit rates for high pressure and for oil. The upper hose is the one that popped on my truck and has the odd fitting and is the reason I had to machine and make up a new line.

  • I have about 12,000 miles on mine now and it is holding strong (knock on wood). Will look and double check size soon, currently driving towards Wyoming in the truck.
    • One added thing. In the pic you can see the part I had to machine, the nut that holds that on is also an AN fitting (army/navy). It is a -6AN. All available through summit racing

    36337865_1698176806945328_9014906998755426304_n.jpg36324097_1698176826945326_7368174979365470208_n.jpg36296971_1698176943611981_317497825199915008_n.jpg
 
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tennmogger

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Thanks for the effort George. Good info.

BTW, the 3116 is a high vibration engine, IMHO, that does not need assistance from the driveline to shake off parts. Has anyone else had trouble keeping an oil pan in place? One of mine had wear marks around all the bolts where the pan was jittering on the engine, and fatigue cracks around several holes. Had to really glue the repaired pan on.

Increasing idle on the engine as soon as possible really reduces vibration too. It helps to bump the hand throttle up to 1200 or so to keep the engine running smoothly while it's sitting. Whatever speed feels best for your engine.
 

ramdough

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Found it...... was on facebook. Had remembered wrong. Was not a loop.... just an extra whoopty do to make it little longer to help reduce vibrations and put the line at a straighter shot with the fittings. Biggest issue seems to be assembly. If they two fittings (one on governor and one on block) where oriented during assembly in a path directly in line with the tube.... it would relieve a lot of the issue.

https://www.facebook.com/groups/1607576859556624/permalink/1975366566110983/

Here is quote of it and borrowed picture
Anyone know if an after market version exists?

Thanks
Doug


Sent from my iPad using Tapatalk
 

AllenF

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OK before we charge off and make a completely new line perhaps we can/should think about some things.
1) Does anyone know what the oil pressure is in this line?

2) Where is it failing at? Is it in the same place, or all over this tube?
3) Looking at the Face Book post adding in a U at the top adds some more tubing to flex which spreads the vibration over a larger area. That could be enough to fix it. Or not. Remember these engines are 20+ years old and, well, to be fair they have been rode hard and put away wet.... a lot.:rolleyes:
4) Making the tube out of Stainless steel instead of a harder steel could be good IF the oil pressure is OK with this material choice.
5) Could a line be made from braided Hydraulic line? or some other type of flexible hydraulic line?

To be fair I am in no way a diesel or hydraulic mechanic or engineer. I have seen that overbuilding one thing to resolve an issue can lead to the problem moving down the line to appear some place else. For example, tube failure fixed and now the small elbows the tube threads into begin to fail.

Sometimes the solution is to accept that this thing is going to fail so we must change it out BEFORE it fails at a reasonable time interval. With this in mind I would think the tube and both of the elbows should be replaced at the same time. Perhaps once a year or two. My guess is it is not that involved, work wise, and it also looks relatively cheap, cost wise. I know it might not be a bad idea to have an extra one in the tool box for those times we are far from home...2cents
 

Reworked LMTV

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Wonder if your harmonic balancer is shot.

Thanks for the effort George. Good info.

BTW, the 3116 is a high vibration engine, IMHO, that does not need assistance from the driveline to shake off parts. Has anyone else had trouble keeping an oil pan in place? One of mine had wear marks around all the bolts where the pan was jittering on the engine, and fatigue cracks around several holes. Had to really glue the repaired pan on.

Increasing idle on the engine as soon as possible really reduces vibration too. It helps to bump the hand throttle up to 1200 or so to keep the engine running smoothly while it's sitting. Whatever speed feels best for your engine.
 
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