Lost the 6.2 (was: May have Lost the 6.2)

[KMeloney]

Is the date code viewable when the engine is installed? Ie if I was buying a used vehicle with a 6.2 could I easily see the date code?

Yes, you can still view it once the engine is installed. As I recall (from posts here) you have to get under your truck to see it, but... Apparently you CAN see it.

 

[Boston]

I have wondered (with no proof) how many dealers did NOT perform the PICO test, but changed the oil, filter and cap, and then charged GM for the test under the recall and sent the customer on their way?

The dealer knows that if the engine fails, GM has extended the engine warranty coverage, so the owner would be covered (and if the engine failed, there could not be a PICO test done).

The dealer doesn’t determine pico test pass/fail., GM does
The results are sent to a special team at GM while your vehicle sits at the dealership They only release it after a Pass ok from GM

 

[KMeloney]

The dealer doesn’t determine pico test pass/fail., GM does
The results are sent to a special team at GM while your vehicle sits at the dealership They only release it after a Pass ok from GM

Pretty sure I've made it through every 6.2 recall/replacement thread here without knowing that. Interesting...

 

[vcode]

Pretty sure I've made it through every 6.2 recall/replacement thread here without knowing that. Interesting...

Never heard that. Guess it makes sense.

 

[WalleyeMikeIII]

The dealer doesn’t determine pico test pass/fail., GM does
The results are sent to a special team at GM while your vehicle sits at the dealership They only release it after a Pass ok from GM

GM programmed their service software to analyze the output of the knock sensor attached to the picoscope , and give a Pass/Fail to the service tech.

Here is one of several YouTube videos of it.

 

[zbad55]

Glad you have your vehicle back now and with a brand new engine, this is the best outcome you could ask for. I would stick with the GM recommended 0w-20 oil as to not void any warranty.

 

[adventurenali92]

Glad you have your vehicle back now and with a brand new engine, this is the best outcome you could ask for. I would stick with the GM recommended 0w-20 oil as to not void any warranty.

So genuine inquiry based on how my curiosity works. Not trying to argue one way or another or offend anyone just asking. Let’s say OP runs thicker non 0W20 oil, whatever weight that may be, in his new replacement engine going forward. Would a dealer tech be able to know just by seeing oil coming out the drain plug from the pan while doing an oil change, and automatically know that it’s not the recommended 0W20? In which case they’d have justification to void the warranty on his new engine? Is a dealer tech going to test the oil on the spot to verify the weight? Not that I’m saying he should or shouldn’t run different weight oil, but unless the dealer tech physically sees him putting different weight oil into the engine, how would the dealer tech know?

 

[JayceeP]

GM programmed their service software to analyze the output of the knock sensor attached to the picoscope , and give a Pass/Fail to the service tech.

Here is one of several YouTube videos of it.

Interesting. The tech was clearly suspicious with the engine noise, and surprised when it passed. lol.

 

[Vladimir2306]

So genuine inquiry based on how my curiosity works. Not trying to argue one way or another or offend anyone just asking. Let’s say OP runs thicker non 0W20 oil, whatever weight that may be, in his new replacement engine going forward. Would a dealer tech be able to know just by seeing oil coming out the drain plug from the pan while doing an oil change, and automatically know that it’s not the recommended 0W20? In which case they’d have justification to void the warranty on his new engine? Is a dealer tech going to test the oil on the spot to verify the weight? Not that I’m saying he should or shouldn’t run different weight oil, but unless the dealer tech physically sees him putting different weight oil into the engine, how would the dealer tech know?

No, of course, no one will study what it is when changing the oil. But for this you have to change it at the dealer to 0-20, and then change it to 0-40 in another place, it's like too much money to maintain the car. But if the engine dies, then the oil will most likely be taken for analysis.

 

[WalleyeMikeIII]

So genuine inquiry based on how my curiosity works. Not trying to argue one way or another or offend anyone just asking. Let’s say OP runs thicker non 0W20 oil, whatever weight that may be, in his new replacement engine going forward. Would a dealer tech be able to know just by seeing oil coming out the drain plug from the pan while doing an oil change, and automatically know that it’s not the recommended 0W20? In which case they’d have justification to void the warranty on his new engine? Is a dealer tech going to test the oil on the spot to verify the weight? Not that I’m saying he should or shouldn’t run different weight oil, but unless the dealer tech physically sees him putting different weight oil into the engine, how would the dealer tech know?

I could probably get away with it at the moment. I had the recall and passed on my original motor, and thus had a 0W40 oil fill cap. The tech did not change it back to a 0W20 cap at the engine swap…so, seems like I’m green lighted by the fill cap

 

[zbad55]

I could probably get away with it at the moment. I had the recall and passed on my original motor, and thus had a 0W40 oil fill cap. The tech did not change it back to a 0W20 cap at the engine swap…so, seems like I’m green lighted by the fill cap

Ya for sure, I wonder what the cost difference at your dealer would be. I would think that the service tech that writes up the oil change order may catch it at some time or another. I don't think GM has a bulletin out for case like yours to remove the 0W-40 cap and replace with a 0W-20 cap and also update the manual in the vehicle.

 

[Stbentoak]

The replacement engine wouldn't come with a new oil cap already installed?

 

[WalleyeMikeIII]

The replacement engine wouldn't come with a new oil cap already installed?

No, oil fill tube us moved over from old engine. Replacement is just the long block

 

[Scarey]

I suspect that using 0w40 would be fine. They would have to prove that using 0w40 was the cause of the failure. That would be a tough argument when part of the fix for suspect motors is using 0w40.

 

[Marky Dissod]

So genuine inquiry based on how my curiosity works. Not trying to argue one way or another or offend anyone just asking.
Let’s say OP runs thicker non 0W20 oil, whatever weight that may be, in his new replacement engine going forward.
Would a dealer tech be able to know just by seeing oil coming out the drain plug from the pan while doing an oil change,
and automatically know that it’s not the recommended 0W20? In which case they’d have justification to void the warranty on his new engine?
Is a dealer tech going to test the oil on the spot to verify the weight?

ANY motor oil that is good enough for the 6.6L L8T (5w30 dexos) and/or the 6.2L LT1 & LT2 (0w40 dexos) is good enough for the L86 & L87.
Actually, with so many similarities between the LT1/LT2 & L86/L87, it's surprising that most arguments in this forum ever favored 0W20 vs 5w30 or 0w40 at all.

ANYWAY

As motor oil ages by use, the 'w' number goes up, and the other number goes down, so 0w40 ages with use to move closer to becoming 5w30.
This does vary by user, by the way - more fuel dilution over time, more uses under 30min, more viscosity breakdown.
(UNused motor oil ages differently. Motor oil is a solution AND also a suspension, given time, things actually settle to the bottom of unused motor oil bottles -
so shake before use, or some of your motor oil's ingredients might literally be laying on the floor of the bottle!)
Long story short, IFF GM were to have motor oil analyzed - they certainly don't have this ability AT the dealership mech bay, so very likely they'd farm it out to Lake Speed Jr's or another boutique oil analysis firm - the older the 0w40, the more fuel dilution, the greater the viscosity breakdown.
So, I guess they'd be able to tell, is the point - except that they'd be able to tell other things about the motor oil's composition as well.
Don't know if they could literally identify the motor oil's 'make and model', unless very recently changed and had not been used up enough.

Whether or not GM would be willing to hold it against anyone, that they used 'vette LT1-spec motor oil in their mere L87 that callED for 0W20 ...
in this particular situation, very highly doubt that GM would be able to legally hold a user 'at fault' / 'to blame' / 'materially responsible'
for using a SUPERIOR-protecting product, especially if it were also a dexos motor oil.

 

[adventurenali92]

I could probably get away with it at the moment. I had the recall and passed on my original motor, and thus had a 0W40 oil fill cap. The tech did not change it back to a 0W20 cap at the engine swap…so, seems like I’m green lighted by the fill cap

I like your line of thinking!

 

[adventurenali92]

No, of course, no one will study what it is when changing the oil. But for this you have to change it at the dealer to 0-20, and then change it to 0-40 in another place, it's like too much money to maintain the car. But if the engine dies, then the oil will most likely be taken for analysis.

Yeah definitely agreed too much work if you’re not changing your own oil and having to take it to the dealer for oil changes for warranty purposes.

 

[Rick10Tahoe]

@WalleyeMikeIII , did you report to NHTSA?

 

[WalleyeMikeIII]

@WalleyeMikeIII , did you report to NHTSA?

Have not done that...in a bit of a holding pattern while I wait to see if GM offers up any goodwill.

 

[WalleyeMikeIII]

Hi Folks; after my engine replacement, I did some Q&A w/ GM Customer Assistance Center regarding the replacement engine. Specifically, I asked them if they could tell me what, if any changes, have been made to the engine that serves as my replacement, so I could have some confidence that it may be more reliable than the one that failed. After a little nudging, and a wait, I did receive information from my contact saying he had been in contact with the brand quality team, and that the new engine has a different design on the connecting rod bearings. This is some good news if true, and I have no reason to doubt it; but am treating it with appropriate suspicion.

I did a little research this afternoon. The P/N of the engine I received was 12740076, which replaces two prior engine P/N's (although I do not know which one I originally had, those are 12705510, and 12716401). Date of manufacture was Nov 13, 2025.
I further looked into the rod bearings and noticed the latest P/N for them is 12735504, which replaced 12683811, which replaced 12763962.

Again, I have no way to know which bearing p/n was in my original engine built in 2022, but suspect my replacement engine has 12735504, consistent with what I have been told by the customer assistance center. No online parts data says when these became the part number of choice.

What these design differences are, I have no way to know. Would probably take some materials engineering work, or some inside information to know for sure.