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9/21/2026 5:03:34 PM EDT
[Last Edit: Alacrity][Edited] [#1]
Quote History
Originally Posted By Foxtrot08:



100% a cover. You know this more than me lol.
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Quote History
Originally Posted By Foxtrot08:
Originally Posted By Alacrity:
Originally Posted By Foxtrot08:
Originally Posted By jough43:
So potentially GM determined the wrong root cause?



No.  


GM issued the wrong fix for the issue.

The root cause stayed the same.
Was it a remedy, or was it cover?





100% a cover. You know this more than me lol.
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.


Tertium non datur
9/21/2026 5:07:30 PM EDT
[Last Edit: Alacrity][Edited] [#2]
Quote History
Originally Posted By xd341:
I wasn't either. It was bullshit to get NHTSA off their back for a while.

So I guess that falls under "cover"

You are in this industry....how in the blue fuck do you make millions of the same part, a part you've been making in some form, for 75 years...and fuck it up his bad?   Surface finish and profile tolerances aren't a new thing.
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Originally Posted By xd341:
Originally Posted By Alacrity:
Was it a remedy, or was it cover?


I wasn't either. It was bullshit to get NHTSA off their back for a while.

So I guess that falls under "cover"

You are in this industry....how in the blue fuck do you make millions of the same part, a part you've been making in some form, for 75 years...and fuck it up his bad?   Surface finish and profile tolerances aren't a new thing.
Si! Tho I think it was a strategic move as was Ford's availing themselves of almost the full administrative process for the valves which were ground without proper temp controls.  You could say GMs 3+ years of reports and subsequent investigations, surely was strategic as well. I know of two L87 that have seized first hand, so this isn't entirely removed from me like the Toyota, Nissan, Jeep, and Ford situations were.

I do a very good  job not speculating. So I'm not going to here with no concrete, direct knowledge. But we can all guess what happened given what's been reported at the supplier, GMs arc recently, and the general issues in supply chain that manifested during COViD which still resonates.


Tertium non datur
9/21/2026 5:11:51 PM EDT
[#3]
Quote History
Originally Posted By mancat:
Friend of mine bought and "built" a big ass jacked up Sierra Denali a few years ago. He is now in the process of offloading it before SHTF.

I'm seeing more and more of these trucks (and Tahoes/Suburbans) with the little Duramax. If I was buying a GMC truck I'd be looking at that engine and nothing else.

Problem is you can't get a good transmission with any of the options.
View Quote


lol don’t look up the baby max issues then
9/21/2026 5:14:48 PM EDT
[#4]
Quote History
Originally Posted By xd341:
Everybody has had production issues. Make millions of something the cheapest way possible and you're going to have a some leakers.  This was literally hundreds of thousands to a million pcs that are no good.
View Quote


It's that bad, and it was that discoverable.
Tertium non datur
9/21/2026 5:29:31 PM EDT
[#5]
Quote History
Originally Posted By Karankawa:
The old TBI engines were the most durable I’ve ever seen. They don’t make enough power to hurt themselves. They did have bad valve seals that would leak after shutdown. Checking for blue tailpipe smoke after sitting a few hours.

I don’t know much about other engines but have big respect for the old boring TBI small block.
View Quote



My '87 Silverado 350 did that. It would give a puff of smoke after startup. I kept the oil checked regularly.
9/21/2026 5:46:20 PM EDT
[#6]
Quote History
Originally Posted By xd341:
A bright GM engineer identified the problem early on, then spent a year trying to explain it to retards in management, then after the retards in management realized just how big of a cluster fuck it was they spent a year trying to come up with a financially palatable solution.  

They never did.

So they designed a new engine and started the financial engineering required to hide the loss in the EV program.

All of this caused by a desire to save 10% on crank machining.


I just pulled all of that out of my ass, but if it happened exactly like that I wouldn't be shocked.
View Quote


Being fair, cranks are not easy to fixture and grind. Not that it’s an excuse for a company that has been doing it well for a decade but resonance over a part that long is a real thing.
Never make another person a priority when they merely see you as an option...

"Some People Are Like Slinkies. They're Not Really Good For Anything, But They Bring a Smile To Your Face When Pushed Down The Stairs."
9/21/2026 6:05:11 PM EDT
[Last Edit: xd341][Edited] [#7]
Quote History
The new LS series was on it's way I'm sure. The LTs are a dozen years old now, they went about as long as the Gen IV "LS".  But I'm sure that played a part in the poor decision making.  Just had to white knuckle it until the LS6.   It's sad because the various versions of the LT are otherwise really nice engines. It was really just the L87 that ate shit.

I'm involved in a big project in the after market taking the now abundant and cheap LT heads, which are excellent and adapting them to other things.  Re-purposing the DI ports for cooling, little weld, little machining...nice light weight block....a slide valve ITB..180 degree headers..and drop it in a 997 GT3.

You'd be surprised how little it takes to bolt Ford stuff to GM stuff....everyone just keeps reusing ideas.
9/21/2026 6:15:08 PM EDT
[#8]
Quote History
Originally Posted By xd341:
The new LS series was on it's way I'm sure. The LTs are a dozen years old now, they went about as long as the Gen IV "LS".  But I'm sure that played a part in the poor decision making.  Just had to white knuckle it until the LS6.   It's sad because the various versions of the LT are otherwise really nice engines. It was really just the L87 that ate shit.

I'm involved in a big project in the after market taking the now abundant and cheap LT heads, which are excellent and adapting them to other things.  Re-purposing the DI ports for cooling, little weld, little machining...nice light weight block....a slide valve ITB..180 degree headers..and drop it in a 997 GT3.

You'd be surprised how little it takes to bolt Ford stuff to GM stuff....everyone just keeps reusing ideas.
View Quote
You make sprint decisions and if the supplier cut right instead of left by inches (or fractions thereof) touch down. But fumbled on the 5.

Love that Bolded.
Tertium non datur
9/21/2026 6:21:13 PM EDT
[#9]
Quote History
Originally Posted By GoGo:
Mexico, not China.

ETA- it's kind of unfair to say, but being involved in powertrain operations in the automotive industry, I have to say sometimes Mexico does OK compared to the US.  For GM, it's the people at General Motors Global Propulsion Systems that was the problem.
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Quote History
Originally Posted By GoGo:
Originally Posted By Lieh-tzu:

How many made-in-China parts in the engine?
Mexico, not China.

ETA- it's kind of unfair to say, but being involved in powertrain operations in the automotive industry, I have to say sometimes Mexico does OK compared to the US.  For GM, it's the people at General Motors Global Propulsion Systems that was the problem.


Having worked in Manufacturing Engineering for a couple of Tier 1 suppliers, I have to disagree.  The Mexico operations I dealt with had a few good engineers and techs, but as a whole they were way short on technical horsepower.  And they don't seem to learn from experience because they never leave anyone with any skills in the same competency long enough to really learn the ropes.  They also tended to be pretty arrogant, which is a bad trait to combine with incompetence.
9/21/2026 6:24:29 PM EDT
[#10]
Quote History
Originally Posted By TheOtherDave:


Being fair, cranks are not easy to fixture and grind. Not that it's an excuse for a company that has been doing it well for a decade but resonance over a part that long is a real thing.
View Quote
Have you seen the dedicated crank machining machines?  They are wild coming from more universal machine tools like lathes or cylindrical grinder.   The old school cam driven crank grinders are pretty cool though.

Not sure what a production process looks like.  Machine, grind, polish?  Or maybe just machine and polish if you've got your shit together?

Mastering the Art of Crankshaft Machining




The errors that are showing up strike me like a machining process gone bad and the polish step (if there was one)  just made them into shiny....shit.  Nobody actually checked anything any better than a set of mics could do. Supposedly they had cranks with over sized journal radii.   Those are the motors that didn't make to their first oil change.

I mean c'mon.
9/21/2026 6:51:33 PM EDT
[#11]
i spend time looking at youtube videos about cars and motors. its scary. the toyota twin turbo supposedly is a horror story. this gm motor has issues. then you look at videos where mechanics get a car that has a misfiring issue and the engine has to be removed from the car to check for just about everything.

and i just watched an old video done by PCA with a experienced porsche mechanic. listening to him describe all the computers, and how you have to connect to porsche to diagnose and how even porsche knows there is a problem with a subsystem but dont know the root cause so they end up replacing parts. was an older vid but the mechanic was talking about a 360 camera system and the cameras would start flaking out and couldnt determine the root cause and just started replacing parts, including re-wiring cable runs and not replacing wiring looms because replacing the looms cost as much as the car. and one of the fixes was to simply run new wires to problematic cameras (just the wire).

the diagnostics on new cars is like something from a f35 jet.

sheese. in the past i had a 240z and an datsun 510. i rebuilt both motors. i could diagnose problems easily and reach things in the engine bay easily. i wish things like that, but modernized would come back but they never will. between the EPA and CAFE the days of easy-to-work-on-cars is long gone unless you have and older car and then finding parts can be an issue.

9/21/2026 6:57:52 PM EDT
[#12]
Quote History
Originally Posted By heavy260:
Probably trace it back to bad surface finishes or poor assembly, I’m going with bad surface finishes. Changing viscosity was never going to fix it.
View Quote





proudly union made, union quality?
My Sister....."Damn girl, get over it, we have all had to get on our knees and suck a dick to get what we wanted."

Great Aunt Florence..."Life is too short to drink cheap booze"
9/21/2026 6:58:56 PM EDT
[#13]
GM and Chevy and Ford as well all have issues, a lot of it brought on by the f'ing government and climate BS.   Take the 5.3 and others that shift from 8 cylinder to only run on 4 at different times to save f'ing emissions.   Throw in bad lifters that fail, cams and shitty transmissions.  

 FWIW I have a 2021 GMC Elevation with the 10 speed transmission.   At 52,000 now with no issues so will see.   I do oil changes every 3 to 4000 not 10,000 which was recommended by GMC and probably Chevy.
9/21/2026 7:05:21 PM EDT
[#14]
I remember when GM expected the dealerships to weld (or bring in a welder) to repair their shitty weld jobs on the roof.  That company will do ANYTHING to avoid accountability.
9/21/2026 7:10:13 PM EDT
[Last Edit: Bloviator][Edited] [#15]
Quote History
Originally Posted By Alacrity:
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.


View Quote


Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.
9/21/2026 7:17:27 PM EDT
[#16]
Quote History
Originally Posted By Kubota3430:





proudly union made, union quality?
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Quote History
Originally Posted By Kubota3430:
Originally Posted By heavy260:
Probably trace it back to bad surface finishes or poor assembly, I’m going with bad surface finishes. Changing viscosity was never going to fix it.





proudly union made, union quality?



At Questum Macimex in Mexico?
9/21/2026 7:34:35 PM EDT
[#17]
Quote History
Originally Posted By Bloviator:


Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.
View Quote
Block stability is a bigger issue than it gets credit for, especially in higher cylinder pressure applications, like forced induction.


9/21/2026 7:57:59 PM EDT
[#18]
Quote History
Originally Posted By jough43:


Never seen a bad head casting?  It was a thing on 2004 5.3 Chevys.  I had one.  Cracks allowing coolant into oil.  Was a certain casting number.  Aluminum heads.
View Quote

I had to pay to replace my 2005 Chevy 5.3 engine for this reason. Coolant finally worked it's way into my crankcase.
9/21/2026 8:20:37 PM EDT
[#19]
I thought this was pretty well known all along and that the viscosity change was a bandaid.
9/21/2026 8:27:14 PM EDT
[#20]
Quote History
Originally Posted By tortilla-flats:
indeed
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Originally Posted By tortilla-flats:
Originally Posted By TaxPayer77:
Pre-AFM/DOD LS engines will outlive us all.
indeed

The best engines ever designed and built. Never again will an engine be this good.
Carpe diem - Seize the day
Carpe per diem - Seize the expense check
9/21/2026 8:36:24 PM EDT
[#21]
Quote History
Originally Posted By staringback05:
The pursuit of perfect is the enemy of good enough

They made great engines 20 years ago....now we have this trash
View Quote

About the time they adopted lean six sigma
9/21/2026 8:38:40 PM EDT
[#22]
To drop $90k on a truck and the engine fails anything short of 250k miles, let alone a few thousand. Scorched fucking earth.
9/21/2026 8:47:30 PM EDT
[#23]
Quote History
Originally Posted By Alacrity:
Better or worse than 2 iterations of ignition switches  under the same part number?


View Quote
Hey, that only killed one guy (well 13 total) and got his fiance prosecuted and sent to prison for negligent homicide.  

But none of them were GM execs, so . . .

"I assure you, Mr. Mowry, that I am quite serious when I ask you to oblige by walking bow-legged."
9/21/2026 8:53:31 PM EDT
[#24]
Quote History
Originally Posted By mancat:
Friend of mine bought and "built" a big ass jacked up Sierra Denali a few years ago. He is now in the process of offloading it before SHTF.

I'm seeing more and more of these trucks (and Tahoes/Suburbans) with the little Duramax. If I was buying a GMC truck I'd be looking at that engine and nothing else.

Problem is you can't get a good transmission with any of the options.
View Quote


If you make it to 100,000 with less than three turbos it’ll be a miracle.
9/21/2026 8:56:09 PM EDT
[#25]
Quote History
Originally Posted By jough43:
So potentially GM determined the wrong root cause?
View Quote


Oh they probably knew.  They just didn't want to replace engines, and they also didn't want to look like they were doing nothing about it, so they changed the oil as either a last-ditch effort or just a stall tactic.
9/21/2026 9:04:15 PM EDT
[Last Edit: jsnappa][Edited] [#26]
Quote History
Originally Posted By Spartan16:
To drop $90k on a truck and the engine fails anything short of 250k miles, let alone a few thousand. Scorched fucking earth.
View Quote

If someone wants to pay $90k for a $60k truck, they don’t seem like the kind of person who thinks that far ahead.
9/21/2026 9:06:20 PM EDT
[#27]
Quote History
Originally Posted By dangerranger61007:
I thought this was pretty well known all along and that the viscosity change was a bandaid.
View Quote


I thought it was pretty well known that GM turns out garbage.
9/21/2026 9:10:29 PM EDT
[#28]
The change in viscosity was just to get vehicles past the warranty period. That is such a cynical solution that the management that came up with it must be slimebags.
9/21/2026 9:17:52 PM EDT
[#29]
Quote History
Originally Posted By DevilsEggAdvocate:
The change in viscosity was just to get vehicles past the warranty period. That is such a cynical solution that the management that came up with it must be slimebags.
View Quote
wait til you hear about the ford/gm 10 speed.
9/21/2026 9:18:21 PM EDT
[Last Edit: gtfoxy][Edited] [#30]
Saw that the other day.

Just as the non-OEM side starts to present enough evidence of the real root cause GM moves to a different engine.

They did admit the cranks will be from a 3rd party vendor.

It would be great if the vette bottom end holds together for me. It’s rare, but there have been some to let go.

I’m also sending in oil samples from the V35A starting this week to keep an eye on that shit show of an engine.

Originally Posted By st0newall:
i spend time looking at youtube videos about cars and motors. its scary. the toyota twin turbo supposedly is a horror story. this gm motor has issues. then you look at videos where mechanics get a car that has a misfiring issue and the engine has to be removed from the car to check for just about everything.

and i just watched an old video done by PCA with a experienced porsche mechanic. listening to him describe all the computers, and how you have to connect to porsche to diagnose and how even porsche knows there is a problem with a subsystem but dont know the root cause so they end up replacing parts. was an older vid but the mechanic was talking about a 360 camera system and the cameras would start flaking out and couldnt determine the root cause and just started replacing parts, including re-wiring cable runs and not replacing wiring looms because replacing the looms cost as much as the car. and one of the fixes was to simply run new wires to problematic cameras (just the wire).

the diagnostics on new cars is like something from a f35 jet.

sheese. in the past i had a 240z and an datsun 510. i rebuilt both motors. i could diagnose problems easily and reach things in the engine bay easily. i wish things like that, but modernized would come back but they never will. between the EPA and CAFE the days of easy-to-work-on-cars is long gone unless you have and older car and then finding parts can be an issue.

View Quote


I believed the Toyota BS of “It’s all been taken care of.” Meanwhile engines replaced this year are still taking shits. Were they built during the time before they were supposedly fixed? I’d like to think they haven’t become that shitty of a company, but my faith is almost completely used up.

I’m just sending in oil samples & making a paper trail in the event the motor starts showing issues.




9/21/2026 9:21:26 PM EDT
[#31]
Quote History
Originally Posted By DevilsEggAdvocate:
The change in viscosity was just to get vehicles past the warranty period. That is such a cynical solution that the management that came up with it must be slimebags.
View Quote


They also extended the warranty to 10 years / 150,000 miles….
Seriously... unTex the Mex..
9/21/2026 9:31:29 PM EDT
[#32]
Quote History
Originally Posted By NwG:


They also extended the warranty to 10 years / 150,000 miles….
View Quote


Maybe they felt forced to extend the warranty because everyone looked at the requirement to switch to 0w-40 as a dick move to get the affected engines past the warranty period.
9/21/2026 9:34:39 PM EDT
[#33]
Quote History
Originally Posted By NwG:


They also extended the warranty to 10 years / 150,000 miles….
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Quote History
Originally Posted By NwG:
Originally Posted By DevilsEggAdvocate:
The change in viscosity was just to get vehicles past the warranty period. That is such a cynical solution that the management that came up with it must be slimebags.


They also extended the warranty to 10 years / 150,000 miles….


Their solution probably was the best available option for that shitshow.
9/21/2026 9:36:06 PM EDT
[Last Edit: gtfoxy][Edited] [#34]
Quote History
Originally Posted By Bloviator:


Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.
View Quote View All Quotes
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Quote History
Originally Posted By Bloviator:
Originally Posted By Alacrity:
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.




Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.

It really is one of the biggest let-downs in bottom end designs I’ve seen since the LS showed how it was supposed to be done.

Not even a 360 thrust bearing…. Wish I would have known before buying one.

The power of the iForce Max is impressive in a 6k lb truck, but fuck me they made a shit engine.
9/21/2026 9:40:20 PM EDT
[#35]
Quote History
Originally Posted By gtfoxy:
Saw that the other day.

Just as the non-OEM side starts to present enough evidence of the real root cause GM moves to a different engine.

They did admit the cranks will be from a 3rd party vendor.

It would be great if the vette bottom end holds together for me. It’s rare, but there have been some to let go.

I’m also sending in oil samples from the V35A starting this week to keep an eye on that shit show of an engine.



I believed the Toyota BS of “It’s all been taken care of.” Meanwhile engines replaced this year are still taking shits. Were they built during the time before they were supposedly fixed? I’d like to think they haven’t become that shitty of a company, but my faith is almost completely used up.

I’m just sending in oil samples & making a paper trail in the event the motor starts showing issues.

View Quote View All Quotes
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Quote History
Originally Posted By gtfoxy:
Saw that the other day.

Just as the non-OEM side starts to present enough evidence of the real root cause GM moves to a different engine.

They did admit the cranks will be from a 3rd party vendor.

It would be great if the vette bottom end holds together for me. It’s rare, but there have been some to let go.

I’m also sending in oil samples from the V35A starting this week to keep an eye on that shit show of an engine.

Originally Posted By st0newall:
i spend time looking at youtube videos about cars and motors. its scary. the toyota twin turbo supposedly is a horror story. this gm motor has issues. then you look at videos where mechanics get a car that has a misfiring issue and the engine has to be removed from the car to check for just about everything.

and i just watched an old video done by PCA with a experienced porsche mechanic. listening to him describe all the computers, and how you have to connect to porsche to diagnose and how even porsche knows there is a problem with a subsystem but dont know the root cause so they end up replacing parts. was an older vid but the mechanic was talking about a 360 camera system and the cameras would start flaking out and couldnt determine the root cause and just started replacing parts, including re-wiring cable runs and not replacing wiring looms because replacing the looms cost as much as the car. and one of the fixes was to simply run new wires to problematic cameras (just the wire).

the diagnostics on new cars is like something from a f35 jet.

sheese. in the past i had a 240z and an datsun 510. i rebuilt both motors. i could diagnose problems easily and reach things in the engine bay easily. i wish things like that, but modernized would come back but they never will. between the EPA and CAFE the days of easy-to-work-on-cars is long gone unless you have and older car and then finding parts can be an issue.



I believed the Toyota BS of “It’s all been taken care of.” Meanwhile engines replaced this year are still taking shits. Were they built during the time before they were supposedly fixed? I’d like to think they haven’t become that shitty of a company, but my faith is almost completely used up.

I’m just sending in oil samples & making a paper trail in the event the motor starts showing issues.



I Do Cars on youtube just did a teardown on a failed engine with 2026 date codes....

WAS TOYOTA RIGHT? I Dive DEEP Into a Failed 2026 Replacement Tundra V35A Twin Turbo V6 Engine!

9/21/2026 9:40:56 PM EDT
[#36]
Quote History
Originally Posted By ExtraHardTaco:


I thought it was pretty well known that GM turns out garbage.
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Quote History
Originally Posted By ExtraHardTaco:
Originally Posted By dangerranger61007:
I thought this was pretty well known all along and that the viscosity change was a bandaid.


I thought it was pretty well known that GM turns out garbage.


There's that too, but it seems all the major automakers have had issues in recent years.
9/21/2026 10:20:25 PM EDT
[#37]
GM just announced the new 8.3L “mongoose” Duramax. (Mongoose being a shot at the Ford “scorpion” 6.7 powerstroke.)

So let’s see if it holds up.  Kinda interesting since they just ended their medium duty line up of trucks.  I wonder if they plan to start producing medium duty in house again.
Direction, not intention, determines destination.

Integrity is the essence of everything successful.
9/21/2026 10:32:08 PM EDT
[#38]
Quote History
Originally Posted By Bloviator:


I Do Cars on youtube just did a teardown on a failed engine with 2026 date codes....

https://www.youtube.com/watch?v=b-EJBxTm9Jc
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Quote History
Originally Posted By Bloviator:
Originally Posted By gtfoxy:
Saw that the other day.

Just as the non-OEM side starts to present enough evidence of the real root cause GM moves to a different engine.

They did admit the cranks will be from a 3rd party vendor.

It would be great if the vette bottom end holds together for me. It’s rare, but there have been some to let go.

I’m also sending in oil samples from the V35A starting this week to keep an eye on that shit show of an engine.

Originally Posted By st0newall:
i spend time looking at youtube videos about cars and motors. its scary. the toyota twin turbo supposedly is a horror story. this gm motor has issues. then you look at videos where mechanics get a car that has a misfiring issue and the engine has to be removed from the car to check for just about everything.

and i just watched an old video done by PCA with a experienced porsche mechanic. listening to him describe all the computers, and how you have to connect to porsche to diagnose and how even porsche knows there is a problem with a subsystem but dont know the root cause so they end up replacing parts. was an older vid but the mechanic was talking about a 360 camera system and the cameras would start flaking out and couldnt determine the root cause and just started replacing parts, including re-wiring cable runs and not replacing wiring looms because replacing the looms cost as much as the car. and one of the fixes was to simply run new wires to problematic cameras (just the wire).

the diagnostics on new cars is like something from a f35 jet.

sheese. in the past i had a 240z and an datsun 510. i rebuilt both motors. i could diagnose problems easily and reach things in the engine bay easily. i wish things like that, but modernized would come back but they never will. between the EPA and CAFE the days of easy-to-work-on-cars is long gone unless you have and older car and then finding parts can be an issue.



I believed the Toyota BS of “It’s all been taken care of.” Meanwhile engines replaced this year are still taking shits. Were they built during the time before they were supposedly fixed? I’d like to think they haven’t become that shitty of a company, but my faith is almost completely used up.

I’m just sending in oil samples & making a paper trail in the event the motor starts showing issues.



I Do Cars on youtube just did a teardown on a failed engine with 2026 date codes....

https://www.youtube.com/watch?v=b-EJBxTm9Jc

Yep, that’s what I was referring to.

Flat out criminal if Toyota lied about the oil filter. Evidence seems to point to they did.
9/21/2026 10:48:53 PM EDT
[Last Edit: gunhand1][Edited] [#39]
Quote History
Originally Posted By xd341:
Have you seen the dedicated crank machining machines?  They are wild coming from more universal machine tools like lathes or cylindrical grinder.   The old school cam driven crank grinders are pretty cool though.

Not sure what a production process looks like.  Machine, grind, polish?  Or maybe just machine and polish if you've got your shit together?

https://www.youtube.com/watch?v=vIDrH0ayrww



The errors that are showing up strike me like a machining process gone bad and the polish step (if there was one)  just made them into shiny....shit.  Nobody actually checked anything any better than a set of mics could do. Supposedly they had cranks with over sized journal radii.   Those are the motors that didn't make to their first oil change.

I mean c'mon.
View Quote
It's done in various ways, even within the same manufacturer. But it usually goes something like:  turn > rough grind > induction harden > finish grind. Then it will go through balancing and journal/pin measurement and stamping for bearing sizes.

Eta: got to throw in drilling passages for rod oiling in there as well
9/21/2026 10:56:03 PM EDT
[#40]
Quote History
Originally Posted By Foxtrot08:
GM just announced the new 8.3L "mongoose" Duramax. (Mongoose being a shot at the Ford "scorpion" 6.7 powerstroke.)

So let's see if it holds up.  Kinda interesting since they just ended their medium duty line up of trucks.  I wonder if they plan to start producing medium duty in house again.
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they've been testing that thing for years now.  The only real systemic problems GM has had with the dmax has been fuel system stuff.  All Bosch.  Be interesting to see if they stick with Denso for the new one. my guess is that they do.  None of the crank bs has been an issue for the diesels.

Cummins I think has a 7.2 in the works as well.  I know for a fact none of these engines are all that close to their mechanical limits, the 6.7 Ford is probably the rubber band stretched the tightest. It does have a CGI block and chunky rods but nothing crazy really.

my guess is 1200 lb/ft will be about it from 6.6 ish sized diesels.  They are all going bigger for some reason..limit of cheap materials or emissions maybe?
9/21/2026 11:08:46 PM EDT
[#41]
Quote History
Originally Posted By xd341:
they've been testing that thing for years now.  The only real systemic problems GM has had with the dmax has been fuel system stuff.  All Bosch.  Be interesting to see if they stick with Denso for the new one. my guess is that they do.  None of the crank bs has been an issue for the diesels.

Cummins I think has a 7.2 in the works as well.  I know for a fact none of these engines are all that close to their mechanical limits, the 6.7 Ford is probably the rubber band stretched the tightest. It does have a CGI block and chunky rods but nothing crazy really.

my guess is 1200 lb/ft will be about it from 6.6 ish sized diesels.  They are all going bigger for some reason..limit of cheap materials or emissions maybe?
View Quote View All Quotes
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Quote History
Originally Posted By xd341:
Originally Posted By Foxtrot08:
GM just announced the new 8.3L "mongoose" Duramax. (Mongoose being a shot at the Ford "scorpion" 6.7 powerstroke.)

So let's see if it holds up.  Kinda interesting since they just ended their medium duty line up of trucks.  I wonder if they plan to start producing medium duty in house again.
they've been testing that thing for years now.  The only real systemic problems GM has had with the dmax has been fuel system stuff.  All Bosch.  Be interesting to see if they stick with Denso for the new one. my guess is that they do.  None of the crank bs has been an issue for the diesels.

Cummins I think has a 7.2 in the works as well.  I know for a fact none of these engines are all that close to their mechanical limits, the 6.7 Ford is probably the rubber band stretched the tightest. It does have a CGI block and chunky rods but nothing crazy really.

my guess is 1200 lb/ft will be about it from 6.6 ish sized diesels.  They are all going bigger for some reason..limit of cheap materials or emissions maybe?



I don’t see the point in the more power / bigger engine in a light to small medium duty truck.

It’s gotta be an emissions thing for 2027.
Direction, not intention, determines destination.

Integrity is the essence of everything successful.
Yesterday 6:21:13 AM EDT
[#42]
Quote History
Originally Posted By gtfoxy:

It really is one of the biggest let-downs in bottom end designs I’ve seen since the LS showed how it was supposed to be done.

Not even a 360 thrust bearing…. Wish I would have known before buying one.

The power of the iForce Max is impressive in a 6k lb truck, but fuck me they made a shit engine.
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Quote History
Originally Posted By gtfoxy:
Originally Posted By Bloviator:
Originally Posted By Alacrity:
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.




Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.

It really is one of the biggest let-downs in bottom end designs I’ve seen since the LS showed how it was supposed to be done.

Not even a 360 thrust bearing…. Wish I would have known before buying one.

The power of the iForce Max is impressive in a 6k lb truck, but fuck me they made a shit engine.

I watched a new video from IDoCARS, he received a letter from Toyota stating his assessment was wrong on the motor he tore down.

He sorta put it back together and did another review, and based on the oil flow path and what Toyota 'said' went wrong, it sounds like Toyota wasn't telling the truth.  

He wasn't able to find the cause but the 180 degree thrust bearing got a lot of attention, plus the fact it was on #3 cyl if I recall.  There were a few other ??s unable to be answered.

We havn't heard the final answer form Toyota, I feel like we have the answer from GM.  

Did you also hear Lake's comments on the 10sp trans, slowing the RPM and not hitting the correct part of he Stribeck Curve?
Yesterday 6:39:32 AM EDT
[#43]
Quote History
Originally Posted By Bloviator:


Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By Bloviator:
Originally Posted By Alacrity:
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.




Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.
Since I'm not speculating  about causation or process with GM. So I sure won't with TMNA/TMC.  In both cases we have NHSTA documentation indicating  mfg explanation.

I'll point out it's easy to think things. To know things is the trick. Prove things - well that's money.

At some point there may be a Meckstroth and Gamble. But Toyota grew from that experience. The Vermont case filed for Tundra owner damages, sole class action, filed in '24, ended with voluntary plaintiff dismissal just about a year ago. GM is contending with multiple actions with a number of large, experienced, capable firms.  DiCello Levitt, Hagens Bermans, etc on the L87 crankshaft /con-rod issues. Capstone is pursuing a separate action targeting AFM. There's others.





Tertium non datur
Yesterday 6:41:40 AM EDT
[Last Edit: Alacrity][Edited] [#44]
Quote History
Originally Posted By DevilsEggAdvocate:
The change in viscosity was just to get vehicles past the warranty period. That is such a cynical solution that the management that came up with it must be slimebags.
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@DevilsEggAdvocate

Do you think that warranty period isn't adequate beyond timing?

All these decisions are strategic and insulative.  


Tertium non datur
Yesterday 6:44:41 AM EDT
[#45]
Did they ask Ford’s thoughts?
Yesterday 7:26:50 AM EDT
[Last Edit: Alacrity][Edited] [#46]
Quote History
Originally Posted By bmarshall1:

I watched a new video from IDoCARS, he received a letter from Toyota stating his assessment was wrong on the motor he tore down.

He sorta put it back together and did another review, and based on the oil flow path and what Toyota 'said' went wrong, it sounds like Toyota wasn't telling the truth.  

He wasn't able to find the cause but the 180 degree thrust bearing got a lot of attention, plus the fact it was on #3 cyl if I recall.  There were a few other ??s unable to be answered.

We havn't heard the final answer form Toyota, I feel like we have the answer from GM.  

Did you also hear Lake's comments on the 10sp trans, slowing the RPM and not hitting the correct part of he Stribeck Curve?
View Quote View All Quotes
View All Quotes
Quote History
Originally Posted By bmarshall1:
Originally Posted By gtfoxy:
Originally Posted By Bloviator:
Originally Posted By Alacrity:
Not entirely rhetorical.  Im curious how people who know shit (read: you ) see it as well.

What's a shame is 500 new posts to cover ground previous and rehash all the shit in about 20 different previous threads covered comprehensively.

It was incredibly unlikely mitigating dilution, increasing film thickness (IIRC the X-axis of the Stribeck curved but fuck me I don't want to consider the math) and whatever Micro-EHL behavior? they were hoping for wasn't going to solve issue related to poor finishing. See I almost paid attention in those threads

But what it did do was buy time for intermediate cases and create both a legal remedy path, while delaying a portion of failures to the future. The outcomes were pretty well predictable and no one should have believed this was an entirely effective remedy. But I beleive a number said that in those threads. So none should be surprised there's further failures. Given the nature of the testing. What we'll never know is the interval of extension nor the number of intermediate cases delayed. Maybe some significantly - tho doubtful permanently.

I hope Toyota exercises their BONK test in a sufficiently useful fashion and correctly diagnoses engines failing. I'm very disappointed to see them go from 'Every engine will be replaced' to an intermediate solution backed by a conditional testing result.




Toyota's problem is much bigger in my opinion.  I think either the main bearings are undersized, or the block itself has stability issues under load (the Lexus SUVs apparently have a much lower failure rate?).  If so, the architecture of the engine itself is so compact there's really no way to fix it short of a redesign.

It really is one of the biggest let-downs in bottom end designs I've seen since the LS showed how it was supposed to be done.

Not even a 360 thrust bearing . Wish I would have known before buying one.

The power of the iForce Max is impressive in a 6k lb truck, but fuck me they made a shit engine.

I watched a new video from IDoCARS, he received a letter from Toyota stating his assessment was wrong on the motor he tore down.

He sorta put it back together and did another review, and based on the oil flow path and what Toyota 'said' went wrong, it sounds like Toyota wasn't telling the truth.  

He wasn't able to find the cause but the 180 degree thrust bearing got a lot of attention, plus the fact it was on #3 cyl if I recall.  There were a few other ??s unable to be answered.

We havn't heard the final answer form Toyota, I feel like we have the answer from GM.  

Did you also hear Lake's comments on the 10sp trans, slowing the RPM and not hitting the correct part of he Stribeck Curve?
If they aren't, and if they knew or should have known, then we're off. Since we aren't, and there's serious money to be made, that's an indication. Of what's not entirely  clear. But it likely means there's  no clear path to causation and liability. In other similar cases, outside Jeep, the actions were early and often.

You have active cases - GM mentioned, 2.7L EB Barkus v Ford, those mfgs also have 1.2L LIH and 2.3L EB cases proceeding, Nissan VC Turbo Becker v Nissan. Jeep and Toyota debris as of yet, do not.

Fair to note the firms involved in GMs current are peeps that had good (at least large, including fees for themselves) resolutions in the LC9 ring and other successful C.A. litigation against large mfgs. In GMs case, those that weren't obviated by the BK.

So tho there's a good deal of speculative conclusions, which generates YouTube clicks and reputational harm, but the lack of movement from civil litigation firm is an element worth  being aware of.

Tertium non datur
Yesterday 7:38:32 AM EDT
[Last Edit: Alacrity][Edited] [#47]
Quote History
Originally Posted By kozaki:
Hey, that only killed one guy (well 13 total) and got his fiance prosecuted and sent to prison for negligent homicide.  

But none of them were GM execs, so . . .

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Quote History
Originally Posted By kozaki:
Originally Posted By Alacrity:
Better or worse than 2 iterations of ignition switches  under the same part number?


Hey, that only killed one guy (well 13 total) and got his fiance prosecuted and sent to prison for negligent homicide.  

But none of them were GM execs, so . . .

124 deaths were compensated, 275 serious injuries. Pretty shit deal when you look at details.

Candice (Candace?) Anderson. GMs knowledge there and the situation surrounding that one, well peeps get exercised about the shit that impacts personally  I suppose.

Tertium non datur
Yesterday 8:16:23 AM EDT
[#48]
Quote History
Originally Posted By xd341:
Have you seen the dedicated crank machining machines?  They are wild coming from more universal machine tools like lathes or cylindrical grinder.   The old school cam driven crank grinders are pretty cool though.

Not sure what a production process looks like.  Machine, grind, polish?  Or maybe just machine and polish if you've got your shit together?

https://www.youtube.com/watch?v=vIDrH0ayrww



The errors that are showing up strike me like a machining process gone bad and the polish step (if there was one)  just made them into shiny....shit.  Nobody actually checked anything any better than a set of mics could do. Supposedly they had cranks with over sized journal radii.   Those are the motors that didn't make to their first oil change.

I mean c'mon.
View Quote View All Quotes
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Quote History
Originally Posted By xd341:
Originally Posted By TheOtherDave:


Being fair, cranks are not easy to fixture and grind. Not that it's an excuse for a company that has been doing it well for a decade but resonance over a part that long is a real thing.
Have you seen the dedicated crank machining machines?  They are wild coming from more universal machine tools like lathes or cylindrical grinder.   The old school cam driven crank grinders are pretty cool though.

Not sure what a production process looks like.  Machine, grind, polish?  Or maybe just machine and polish if you've got your shit together?

https://www.youtube.com/watch?v=vIDrH0ayrww



The errors that are showing up strike me like a machining process gone bad and the polish step (if there was one)  just made them into shiny....shit.  Nobody actually checked anything any better than a set of mics could do. Supposedly they had cranks with over sized journal radii.   Those are the motors that didn't make to their first oil change.

I mean c'mon.


You know how heavy those old machines were, maybe the same stability is not present in the new machines. Going from cams to linear motors or drives running on smaller bearing surfaces creates an environment for unwanted harmonics to develop. Maybe it's not as much a GM problem as it is a machine tool builder problem. Of course demand may be pushing the production schedule beyond designed capacity as well.
Life's battles don't always go to the stronger or faster man. In the end, the one who wins is the one who thinks he can! - SCI, NRA
Team Ranstad
Yesterday 8:21:21 AM EDT
[#49]
Typical Garage Mechanics Companion CYA. Build junk. Fix(no fix)with different oil. Saw similar shit with their Garbage in the '90's/early 00's. If they'd spend the same money on building good stuff as they do on their Kool Aid, they might have a sellable product.
Yesterday 8:25:48 AM EDT
[#50]
There’s more than one issue. Some are poor machining, some are bad casting, some are bad heat treat.

I’ve seen them take everything apart, chuck the blocks, and put everything back into a new blocks. I don’t mean once here and there. I mean batches of trucks.

I’ve always seen it as GM are prone to electrical issues, Ford is suspension and turbos, and Chrysler is everything. But GM is just racking up a bad history here.

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