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Who trusts the 25's with the revamped 6.2l

MTY55
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MTY55 Enthusiast

MTY55

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I'm sitting on the fence looking at 25 AT4 but can't decide on the 6.2 or the babymax. I hear a lot of emission issues with the 3.0. Not liking the reputation of the 6.2's over the past couple years. I have a 23 Denali 5.3 right now, I'd rather get an AT4 this time but no 5.3 offered.

tjonesdfw Enthusiast

tjonesdfw

Posted
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I've been told by an acquaintance who is a GM service manager that they have had 2025 6.2 trucks blow up already as well.  We have several recalled 6.2 trucks and they advised we either buy 5.3s for now, go to another brand, or wait until the 6.2 L87 has been discontinued and replaced by the 6th gen small block.   Time will only tell if the 6th gen likes to eat lifters, cams, and bearings like the current generation though.  

MTY55 Enthusiast

MTY55

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14 hours ago, tjonesdfw said:

I've been told by an acquaintance who is a GM service manager that they have had 2025 6.2 trucks blow up already as well.  We have several recalled 6.2 trucks and they advised we either buy 5.3s for now, go to another brand, or wait until the 6.2 L87 has been discontinued and replaced by the 6th gen small block.   Time will only tell if the 6th gen likes to eat lifters, cams, and bearings like the current generation though.  

Pretty sad GM can't get their act together. I might just bite the bullet give up a couple more MPG and get a 2500 AT4 with a 6.6 gasser

newdude Senior Enthusiast

newdude

Posted
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The only thing "revamped" about the 6.2 in a 2025 is the "added quality control and production enhancements".  AKA they hopefully stopped being stupid in the machining and manufacturing of the parts to build an engine that will run right.  

 

There has been 2025s though that have had these fail already so...keep that in mind to their "enhancements".  Some got built before the changes.  

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Silverado4x4 Senior Enthusiast

Silverado4x4

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Exactly what newdude said some these 25s may still have the motors before the changes were corrected to the engine. Built shipped and gone to the dealers that's why the dealers had to do a stop sale to do the tests in there inventory before sale.

tjonesdfw Enthusiast

tjonesdfw

Posted
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I guess the question is whether you trust what GM says, for example in its statement to GM Authority "A series of crankshaft and connecting rod manufacturing improvements implemented on or before June 1st, 2004, addressed contamination and quality issues.  Model-year 2025 vehicles were built after these improvements and are not included in the recall."  Its probably too soon to tell if the 2025 trucks that have failed are within the normal accepted rate of engine failure for modern vehicles, OR if they are failing in the same way as the recalled motors.  If they are failing in the same way, that tells us GM either doesn't have a clue what is causing the issue yet, or they didn't make any manufacturing changes.  Either way it tells me to stay away from the L87 for the foreseeable future.  

Atlas Senior Enthusiast

Atlas

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I'd think GM is being very careful about what they tell customers at the moment seeing how the 6.2 issue is wrapped up in a recall and class-action.

 

That said, I wanted something a little better on fuel and I like the way the LZ0 turbo-diesel pulls. Emission issues don't scare me, I've owned other modern diesels, and I also don't think issues are widespread with the LZ0...

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MTY55 Enthusiast

MTY55

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4 hours ago, Atlas said:

I'd think GM is being very careful about what they tell customers at the moment seeing how the 6.2 issue is wrapped up in a recall and class-action.

 

That said, I wanted something a little better on fuel and I like the way the LZ0 turbo-diesel pulls. Emission issues don't scare me, I've owned other modern diesels, and I also don't think issues are widespread with the LZ0...

My only concern is my driving is mostly short city drives. I'm sure longer highway drives would be better for the LZO.  The fuel cost in my area, Diesel and premium are pretty close in price. Def just adds more cost to the LZO. My 23 Denali 5.3 is a great vehicle. I should just keep it  but I get bored very easily with my vehicles. I have an oil change due in a couple weeks with too many decisions to make with these engines. This wouldn't be the first time I left for an oil change only to go back to the dealer with my title and a check, then drove home later with a new truck, Decisions decisions.

Bikerjon Enthusiast

Bikerjon

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On 7/14/2025 at 4:27 PM, MTY55 said:

I'm sitting on the fence looking at 25 AT4 but can't decide on the 6.2 or the babymax. I hear a lot of emission issues with the 3.0. Not liking the reputation of the 6.2's over the past couple years. I have a 23 Denali 5.3 right now, I'd rather get an AT4 this time but no 5.3 offered.

I do and I'm driving one right now. The crankshaft/bearing issue has been resolved according to GM. My Service Manager has assured me that there are no further issues and mine is running great. I personally would never own a diesel. I've worked on many diesels and cant stand them. I also think the fuel stinks. If your worried about the 6.2 engine don't test drive one because if you do you will buy it!

 

Good luck on your decision.

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MTY55 Enthusiast

MTY55

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On 7/15/2025 at 11:35 PM, Bikerjon said:

I do and I'm driving one right now. The crankshaft/bearing issue has been resolved according to GM. My Service Manager has assured me that there are no further issues and mine is running great. I personally would never own a diesel. I've worked on many diesels and cant stand them. I also think the fuel stinks. If your worried about the 6.2 engine don't test drive one because if you do you will buy it!

 

Good luck on your decision.

Bikerjon. you are absolutely right I test drove a 25 Denali 6.2 yesterday. Was so impressed I'm picking it up in about an hour. I guess the old guy in me told get the Denali and not the AT4. I like comfort and don't need the offroad capablities

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Z45 Senior Enthusiast

Z45

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According to internet gossip they 6.2L issue revolved around crankshafts that were OUT-SOURCED to a supplier in Mexico, to save $$. Since mid 2024 production shifted back to the GM engine plant in Tonawanda, NY. 

 

 

BIGDOGx Senior Enthusiast

BIGDOGx

Posted
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On 7/30/2025 at 6:08 AM, Z45 said:

According to internet gossip they 6.2L issue revolved around crankshafts that were OUT-SOURCED to a supplier in Mexico, to save $$. Since mid 2024 production shifted back to the GM engine plant in Tonawanda, NY. 

 

 

 

 

Shocker that using 5 dollar per hour Mexican slaves would yield piss poor results.

 

And it's not gossip here is a picture of a brand new engine tear down showing the crank shaft journal looking like it was finished with a coarse metal file. 

1752079328850.png

Z45 Senior Enthusiast

Z45

Posted
Posted (edited)

My brother's been driving a 2025 Sierra SLT CC 6.2L since last fall and its going strong.   I don't believe rumors that cranks made at Tonawanda are just as bad. If that was the case, all the Vette engines, 6.6L and 5.3L cranks they produce would be bad.  That BS is from people with an axe to grind with GM so they make stuff up.  

 

GM was doing everything to reduce the US workforce so the contracted out to foreign companies and it came back in bit in the you know what.  

Edited by Z45
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Jus Cruisin Enthusiast

Jus Cruisin

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At this point I wouldn't be concerned with a 2026 6.2l. But, right now I'm really happy with this 3.0l Duramax. I ran across the state (Michigan) yesterday to check out a street rod and both ways the current trip showed 30+ mpg. Diesel is less than premium and better mpg. Yeah, the 6.2l sounds better, though. 

PunchT37 Enthusiast

PunchT37

Posted
Posted (edited)
On 7/31/2025 at 9:45 AM, BIGDOGx said:

 

 

Shocker that using 5 dollar per hour Mexican slaves would yield piss poor results.

 

And it's not gossip here is a picture of a brand new engine tear down showing the crank shaft journal looking like it was finished with a coarse metal file. 

1752079328850.png

Brand new engine tear down? Wonder why that one was chosen? That engine wouldn`t make it off the assy line and definitely not last the 1`st  PDI test drive. If that pic is real.

Edited by PunchT37

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