Working on diagram of Cat 3116 common failure points

[Awesomeness]

I think this approach is great. As has been mentioned, there is a great deal of excellent information here. But it is all over the place and requires a long and involved search to find it. I was thinking more along the lines of something like Fuel System, Coolant System, CTIS System, Electrical System etc. After each system is listed then have a brake down list of each component for this system and then all of the info there to resolve every known issue including TSM's and after market part numbers and places to get them from. This could be done for the 3116, 3126 and C7. Each needs it own place to better focus on only one and not all 3. Yes this will present some common things being posted three times but it will be complete for each type. There could also be sections for issues unique to the different versions such as M 1078, 1083, ect. Also A0,A1 ect. A unified format would also be needed to eliminate confusion and simplify searching.
I know a ton of work but in the end it could make every ones life a lot better. Most likely this would become a new section with factual info only unlike the forum threads with a lot of unnecessary applause and chit chat. Which I love but is in the way of having a faster way to get what is needed to solve our issues. My

Are you aware of the TMs (Technical Manuals)? This is a fairly close description of the TMs themselves, which are complete with individual instructions on how to repair/replace most individual components, toubleshooting guides, wiring diagrams, etc. Also worth pointing out is that the full set of TMs is several thousand pages long in order to cover all that content.

 

[AllenF]

Yes I have downloaded all of them. I have not read all of them as IMO that would in itself be an undertaking I am not prepared for. I may be wrong here but the original poster was looking to find out and create a most likely to fail list for the engine. I think in particular the items that would cause the greatest damage. Once compiled/ identified add the solutions. While the TM's have how to trouble shoot and fix, they don't include the data of over time these areas we now know to be weak parts to check. We here are the ones who are trying to stop/check before they catastrophically fail. Also IMO TM's don't have part numbers and part sources to same items at lower cost or even available other than the U S Government. We all know how difficult and expensive this can be.

 

[AllenF]

Just to add the TM's are great to have but in my very limited experience difficult to actually dig through to find what is needed. Perhaps it is my actual limited understanding of their lay out but short of printing them and creating a book searching through them on a device is very very slow

 

[Coffey1]

My recommendation is to remove that rubber on fan immediately! It can fail at any time.
There are holes on fan blade that match perfectly with holes on hub I have bolted blade to hub on every truck I've owned! Absolutely zero issues.
Small bolts with lock nuts.

 

[Reworked LMTV]

Thanks for your input. Would you happen to know the newer fan part number? Or wait, are you saying you can mod the basic fan?

My recommendation is to remove that rubber on fan immediately! It can fail at any time.
There are holes on fan blade that match perfectly with holes on hub I have bolted blade to hub on every truck I've owned! Absolutely zero issues.
Small bolts with lock nuts.

 

[Reworked LMTV]

They are set up that way so that the enemy gives up trying to figure out our stuff

Just to add the TM's are great to have but in my very limited experience difficult to actually dig through to find what is needed. Perhaps it is my actual limited understanding of their lay out but short of printing them and creating a book searching through them on a device is very very slow

 

[Reworked LMTV]

check the small bolts that hold the shoes in on fan clutch

Shortly after purchased my m1088, I had it running and heard several clinks. Nothing major I thought. I found the several pieces of clutch lying in my driveway. The fan could not engage, and thus would overheat if it was driven slow. Check the small bolts that hold the plates that hold these in. Loctite them.

 

[Awesomeness]

Thanks for your input. Would you happen to know the newer fan part number? Or wait, are you saying you can mod the basic fan?

It's in the TMs. Anywhere the TM talks about removing the fan (including for other unrelated reasons, like during an engine swap), it has a note that says something about discarding the old fan and clutch, and using the new part numbers. You have to change them both, by the way, as the new fan does not fit the old clutch.

I disagree with Coffey's assertion that it needs to be changed immediately just because it could "fail at any time". That's technically true of everything, and there are a lot of "several hundred dollar" projects that each of our trucks needs, and making this too high a priority could deprioritize something else that could have even worse consequences... you'll have to decide for yourself. I've only seen a couple posts about it failing - it's not like we're seeing them with any frequency. It's all a matter of whether your rubber ring is in good shape, or has deteriorated. If it's good, you'll get years of use out of it. To replace the clutch and fan costs several hundred dollars, and potentially saves you replacing a radiator (also several hundred dollars). Checking the ring for deterioration and slop is quick and free, and significantly reduces the [already small] risk.

We don't know what the long term ramifications are of the suggestion to just remove the rubber ring and bolt the fan to the clutch. The engineers put the rubber ring in there for a reason, and completely switched both the fan and clutch to new models several years later. Never did they make the suggestion to Army mechanics to just remove the rubber ring, so either they just didn't think of it, or they did think of it and there was a good reason to not do it that way and swap to totally different fan and clutch. Taking that suggestion could be just as much of a gamble than leaving the rubber ring in there. Maybe they had to switch the clutch because the original clutch couldn't handle the vibration without the ring in there? A better idea, than just removing it, would be to make a replacement rubber ring, which could be done several different ways (e.g. cut a ring from a heavy rubber horse stall mat, make a mold and cast one, etc.).

 

[Reworked LMTV]

Do you have a source for the clutch ? I was thinking closer to $600-1000 for the clutch (new retail)

It's in the TMs. Anywhere the TM talks about removing the fan (including for other unrelated reasons, like during an engine swap), it has a note that says something about discarding the old fan and clutch, and using the new part numbers. You have to change them both, by the way, as the new fan does not fit the old clutch.

I disagree with Coffey's assertion that it needs to be changed immediately just because it could "fail at any time". That's technically true of everything, and there are a lot of "several hundred dollar" projects that each of our trucks needs, and making this too high a priority could deprioritize something else that could have even worse consequences... you'll have to decide for yourself. I've only seen a couple posts about it failing - it's not like we're seeing them with any frequency. It's all a matter of whether your rubber ring is in good shape, or has deteriorated. If it's good, you'll get years of use out of it. To replace the clutch and fan costs several hundred dollars, and potentially saves you replacing a radiator (also several hundred dollars). Checking the ring for deterioration and slop is quick and free, and significantly reduces the [already small] risk.

We don't know what the long term ramifications are of the suggestion to just remove the rubber ring and bolt the fan to the clutch. The engineers put the rubber ring in there for a reason, and completely switched both the fan and clutch to new models several years later. Never did they make the suggestion to Army mechanics to just remove the rubber ring, so either they just didn't think of it, or they did think of it and there was a good reason to not do it that way and swap to totally different fan and clutch. Taking that suggestion could be just as much of a gamble than leaving the rubber ring in there. Maybe they had to switch the clutch because the original clutch couldn't handle the vibration without the ring in there? A better idea, than just removing it, would be to make a replacement rubber ring, which could be done several different ways (e.g. cut a ring from a heavy rubber horse stall mat, make a mold and cast one, etc.).

 

[Reworked LMTV]

I think I recall someone saying their fan caught the small air hose too. Is that right? I know it is rare, but that one is a cheap, but PITA fix.

 

[Awesomeness]

Do you have a source for the clutch ? I was thinking closer to $600-1000 for the clutch (new retail)

It's a standard commercial part, I think. My old clutch had stopped turning off (stuck on), so I replaced it. I bought it new online somewhere for about $375 or $475. I tried to put the old fan back on it, found it didn't fit, and bought a NOS of the new fan type from eBay for about $100.

The part number for the new clutch is in my part number spreadsheet, here in my signature. If you mouse over the "fan clutch" cell, you'll also see I added a comment with the exact wording of the replacement notes from the TM, and the new fan's part number.

I think I recall someone saying their fan caught the small air hose too. Is that right? I know it is rare, but that one is a cheap, but PITA fix.

I remember that post, maybe about 6 months ago. I think that's the only one I've seen on the subject. It's not difficult to replace (<10 minutes). You would have to find one, or probably just have one made (would be easier).

 

[Coffey1]

Yes all you have to do is take fan off
Throw rubber away bolt fan to hub.

 

[Reworked LMTV]

Nice job on those links. Lots of good info. I will link to your Google info sheet.

It's a standard commercial part, I think. My old clutch had stopped turning off (stuck on), so I replaced it. I bought it new online somewhere for about $375 or $475. I tried to put the old fan back on it, found it didn't fit, and bought a NOS of the new fan type from eBay for about $100.

The part number for the new clutch is in my part number spreadsheet, here in my signature. If you mouse over the "fan clutch" cell, you'll also see I added a comment with the exact wording of the replacement notes from the TM, and the new fan's part number.


I remember that post, maybe about 6 months ago. I think that's the only one I've seen on the subject. It's not difficult to replace (<10 minutes). You would have to find one, or probably just have one made (would be easier).

 

[Coffey1]

If the solenoid under fuse panel behind kick plate is not working it won't let air off of clutch to engage fan.
That solenoid is junk I replace with better one.

If ever out on road and fan won't come on take hose off at top of shroud and kink over and tape or wire tie and fan should come on and stay on.

 

[Reworked LMTV]

Excellent input. Do you have an upgraded solenoid model number by chance?

If the solenoid under fuse panel behind kick plate is not working it won't let air off of clutch to engage fan.
That solenoid is junk I replace with better one.

If ever out on road and fan won't come on take hose off at top of shroud and kink over and tape or wire tie and fan should come on and stay on.

 

[Reworked LMTV]

Me thinks a Magnflux plastic penetrant, maybe every 5k miles, to look for stress cracks?

Magnflux
[h=1]ZL-4C[/h][h=2]Water-Based Fluorescent Penetrant[/h]

Yes all you have to do is take fan off
Throw rubber away bolt fan to hub.

 

[jkcondrey]

I think I recall someone saying their fan caught the small air hose too. Is that right? I know it is rare, but that one is a cheap, but PITA fix.

That was my truck, with the previous owner. It had the front cover issue and the fan got ahold of the air hose. All resolved at the moment lol.

 

[Reworked LMTV]

Do you mean the shroud?

That was my truck, with the previous owner. It had the front cover issue and the fan got ahold of the air hose. All resolved at the moment lol.

 

[Coffey1]

The new and improved clutch also requires a new blade.

 

[jkcondrey]

Do you mean the shroud?

No, it had a leaking front cover due to vibration as well. It was repaired and then after reassembly, the hose must have been in wrong position and got chewed up by the fan at a later date.