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NHTSA Preliminary Investigation into Crankshaft failures

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#61 ·
NavyCuda said:
I’m not trying to make excuses for them, but they’re going to fight this tooth and nail.
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Yes, I agree, but they have limited recourse if the NHTSA orders a recall or some form of remediation for safety purposes. The NHTSA is not really interested in how much money Cummins and Nissan lost, or how expensive it is to repair this engine or if the consumer got a raw deal from either--not any of that. It is only the safety implications of sudden engine failure. If there is a large enough statistical risk that this can happen to many engines, they will act. I think you are right...the failures are nuanced and varied. Some seem to be sudden catastrophic crankshaft failure not related to spun bearing. Those are the most compelling from a safety perspective. Spun bearings that allow you to drive for a while--bad engineering and damn bad luck perhaps, but not as big of a safety issue.

So it will all come down to the data and what the numbers really say. I love that they (NHTSA) are also going after and WILL GET all the internal emails/communication and such. That kind of stuff is invaluable. It could show that both Nissan and Cummins were aware of all of this and had no idea why and just pressed ahead with a couple of parts changes or vendor changes. Do they even KNOW what to do to fix this. I really hope there is a detailed report at the end of the line that goes through it all regardless of if they end up ordering action or not. It is pretty easy to use the Freedom of Information Act (FOIA) to make a request for something like a report/conclusions if it doesn't get posted.

It s going to take a while for sure for this to play out which is also no help to those whose engines break in the meantime.
 
Discussion starter · #62 ·
The issue is that the nature of the failure is such that the blame can be passed off onto the consumer.

Look at the acceptable oil consumption rates for our engine. We use post fuel, we we have have oil thinning issues. The crankshaft failures, at least every picture I’ve seen is a nearly clear cut failure due to flexing the crank well outside of concentric with the bearings. The fracture position suggests it’s breaking during the combustion event.

I think that Cummins and Nissan will be able to argue that the crankshaft failure is a symptom of end user neglect.

Things like, not dealing with a clogged egr valve, changes effective timing, adds more heat to the oil.

There is a lot more interesting tid bits I can’t cover in an authorative way, but it appears there are multiple failure modes that end in crankshaft failure. Too many of them could be argued as a failure of the end user to adequatey maintain the engine. That won’t be the case for everyone, but it might be enough for them to squeak out of it.
 
#63 ·
NavyCuda said:
Too many of them could be argued as a failure of the end user to adequatey maintain the engine. That won’t be the case for everyone, but it might be enough for them to squeak out of it.
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Good point. That would indeed provide a way out. Unless they also uncover emails and the like that refute that...which is possible. That would be like Boeing with 737 Max 8/9 crashes. The NTSB got emails from Boeing's two chief test pilot for the MAX talking about the MCAS flight control software and how one of them was planning to "...use the Force..." on the FAA guys when dealing with the certification. They knew of the problems but kept forging ahead so they wouldn't have to require additional training for the MCAS system. It would have been funny if it wasn't so tragic and pathetic

That would be a smoking gun, but there may not be anything like that here...
 
#64 ·
NavyCuda said:
The fracture position suggests it’s breaking during the combustion event.
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That suggests either a bad batch of forgings, faulty machining, or simply and under-designed part for the application. It is this catepory that really gets--and worries--me as the owner of a 2016. No matter how well you maintain the truck it can be a ticking time bomb for one of these reasons. But like you said, are there enough of these to matter statistically?
 
Discussion starter · #66 ·
Vann5 said:
That suggests either a bad batch of forgings, faulty machining, or simply and under-designed part for the application. It is this catepory that really gets--and worries--me as the owner of a 2016. No matter how well you maintain the truck it can be a ticking time bomb for one of these reasons. But like you said, are there enough of these to matter statistically?
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I think the most important thing is watch oil pressure and temperature. If the oil pressure falls or some other means of the bearing clearance getting too generous, the crank can flex and then break.
 
#67 ·
Guess Im Walking said:
Nah no tuning involved,platinum reserve 4x4 2016. It had nothing but problems from the start,in and out of the dealer several times for multiple issues. Bummer tho this is the 5th Nissan truck that I’ve owned and all the others were great trucks,contacted nissan about all the problems cuz it was still under warranty when it started but they told me that it was not eligible for a buyback.So now I’m contemplating an engine swap.
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I have the same 2016 platinum reserve truck. Was doing 50 and lost all power, found out it was the motor. Truck had 70k miles on it and needed a new motor
 
#69 ·
NavyCuda said:
It’s almost certainly not the harness. I’m convinced he said that to sound smart and drive sales. Listen to him long enough and you’ll realize he knows about as much about this engine as the sales people at Nissan do.
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Yeah I watched another video of a guy with a failed crankshaft and he meticulously checked the wiring harness and that wasn't the issue.
 
#70 ·
thegreatbasinrockies said:
I wonder how long it takes to complete these investigations
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Their inquiry was a preliminary evaluation. The NHTSA website says they shoot for a deadline of 8 months, and it has now been 16 months already. The request for information from Nissan has a deadline of March 11th. Sounds like they are only getting started.

From the letter sent to Nissan, the following language was submitted:
Due Date
Nissan’s response to this letter must be submitted to this office by March 11, 2024. If Nissan
finds that it is unable to provide all of the information requested within the time allotted, Nissan
must request an extension from me at (202) 366-6938 no later than five business days before the
response due date. If Nissan is unable to provide all of the information requested by the original
deadline, it must submit a partial response by the original deadline with whatever information
Nissan then has available, even if an extension has been granted.
If you have any technical questions concerning this matter, please call...
 
#71 ·
NavyCuda said:
I think the most important thing is watch oil pressure and temperature. If the oil pressure falls or some other means of the bearing clearance getting too generous, the crank can flex and then break.
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What do you mean by the bearing clearance getting too generous? Also, is the oil pressure dropping something that could get caught in time with real time monitoring? It sounds like a lot of people are saying it just happened out of no where. It would be great if there was a warning sign. I drive under 70 at all times and I try not to rev the engine very much, but it worries me that any time it could give.
 
Discussion starter · #72 ·
thegreatbasinrockies said:
What do you mean by the bearing clearance getting too generous? Also, is the oil pressure dropping something that could get caught in time with real time monitoring? It sounds like a lot of people are saying it just happened out of no where. It would be great if there was a warning sign. I drive under 70 at all times and I try not to rev the engine very much, but it worries me that any time it could give.
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Well if the oil pressure falls off and is not properly supporting the crankshaft then the crankshaft can start to deform under load or even come in contact with the bearings. Once the crankshaft comes into contact with the bearings, things start accellerating.

Actually, getting into rpm is better for the engine but not always fuel consumption. The faster the crankshaft spins, the more
it wants to stay concentric to the bearings. Also, the faster the crankshaft is spinning, the more degrees of rotation it takes for the combustion pressures to act on the crankshaft. At idle, it might only take say, 50 degrees of rotation to complete combustion but might take 70 or 80 degrees at wide open.

Oil pressure drop would be one of those things where you get used to the engine and see where the pressure and temperature sit at normal operating conditions. Then you can see when something is out of the ordinary and start looking for possibilites.

It’s going to be a pretty substantial change too.

I think one of the reasons the crankshafts go without warning is how smooth these engines naturally are. By the time they really start making noise it’s far too late, unless you’re really in tune with your engine.

Getting a real oil pressure gauge in the truck should be considered mandatory for anyone who wants to get some warning. It might not be a lot of warning, but it might be enough to save the engine, maybe the crank.
 
#77 · (Edited)
Looks like there is movement on the investigation. They are heavily redacted so it is hard to interpret, but there are several new uploaded documents. In the first image, it's a list of vehicles by date sold, and the parts they have as it relates to the engine block, crankshaft, bearings, and bearing cap bolt. The second image shows changes to engine parts over time, which based on parts numbers, are associated with the crankshaft and the cylinder block and with an explanation as to why the changes were made.
It's too bad we can't see the reasoning, as this would be helpful for many while the investigation plays out. It should shed light on their knowledge of the problems, if these different part numbers corrected the breakage issues, and if this is a tractable issue with crankshaft modifications or if it is some other systems issue that is the cause.

Image


Image
 
#78 ·
anyone notice any updates on the investigation? I saw on the Facebook forum that one owner had Nissan customer service step in and offer half of engine/turbo parts but not labor. Maybe that’s signs of them realizing something? Wouldn’t be so bad if you could have Nissan repair it for 10-13k (I’m almost at 100k miles) but with a good warranty on the rebuild.
Still leaving mine stock in hopes of something.
 
#79 ·
forgivenjhn316 said:
Question:
Has anyone on here who has had the come apart issue already replaced their motor? If so would ya point me in the right direction as to where you purchased from?? Thanks!
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i have replaced mine, it had 72000 on it and the motor blew going down the road. I found a company online that had a rebuilt motor for around 20k
 
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Vann5
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