Thinking of selling my new 6.2L Denali...

[2024 White Tahoe]

They would have to prove that the oil caused the issue (links to the federal trade commission's and USCode government websites regarding the Magnuson-Moss warranty act are below,,, or you can google the Cliff notes version of the Magnuson-Moss act that says in a nut shell that to deny a warranty , they have to prove the fault).

And if the engine fails (which is kind of a thing with the 6.2 right now) , nowhere does it tell the mouth breathing computer screen reader dealership tech that's diagnosing the issue to check the oil weight. They do ONLY what the screen tells them to,,, and the screen tells them to visually look for metal in the oil, not send the oil out for analysis.

The recommendation of 0W-20 oil is purely for CAFE reasons. I'd rather have my engine live a healthy life, and still be around past the warranty period, rather than just barley get out of the warranty period with a clapped out engine because of some irrational fear of warranty denial.

Magnuson Moss Warranty-Federal Trade Commission Improvements Act

Title I of this Act authorizes the Federal Trade Commission to develop regulations for written warranties.

www.ftc.gov

https://uscode.house.gov/view.xhtml?req=granuleid%3AUSC-prelim-title15-chapter50&edition=prelim

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If an authorized dealer denies warranty coverage due to owner non compliance with maintenance or modification, they flag the computer for the vehicle so all other dealers know.

Then, YOU must sue them to enforce the warranty. You may eventually win, but it will take time and money - while your vehicle is not repaired (and may be not drivable).

Modify a vehicle under the new-car warranty or using non-specified maintenance items (such as oil, engine “tunes”, etc.) is asking for problems.

 

[Antonm]

Guess they got the sheepeople good and scared.

Its still free country, run all the CAFE recommended crap you want I suppose.
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[Blueinterceptor]

I might be in the minority here, but I can’t afford the loss of a hundred thousand truck or to replace an 8,000$ engine. Or pay for a lawsuit against a mega corporation like gm.

 

[Antonm]

I might be in the minority here, but I can’t afford the loss of a hundred thousand truck or to replace an 8,000$ engine. Or pay for a lawsuit against a mega corporation like gm.

One owner is small potatoes to GM. The 6.2 has a known issue (complete with its own NHTSA investigation). They know it has issues and unfortunately , its all to common they go boom. Its not worth their time to deny a warranty when they know there is an issue.

But lets say for some strange reason they try to, one letter from a blood sucking lawyer and they'll pay, not because they want to do the right thing, but because its cheaper for them to pay than fight it for one unit.

You're more in danger of losing $100K because of some random pedestrian jumping on your hood, then claiming you hit them and sue, then you are of having GM deny a warranty claim on a 21+ model year 6.2. But I'd bet you still drive in the city with pedestrians walking around.
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[jfoj]

The dealer will never take an oil sample for analysis, it takes time (approximately 10-14 days for mail transit time and lab time) and money. If they sample out fuel diluted oil, if you were running 5W30 or 0W40 it will probably look like 0W20 anyway at best, but if you are running something heavier than 0W20, I would bet your engine would not have failed if you are doing other things like running Premium fuel as well. I am surprised the dealers do not at drain the oil on failed engines and measure the oil volume in the crankcase, many of the engine failures are likely running close to 2 quarts low on oil due to oil consumption of fuel diluted oil. The dealer could possibly deny warranty coverage for the engine being run low on oil as well.

I am convinced base on some data gathering a majority of the 6.2l engine failures are caused by the use of 0W20 engine oil, yes this is the spec oil, but not likely useful for real world conditions. At 0 miles on the oil, 0W20 is probably borderline adequate. As the oil has miles put on it, the oil starts to get diluted with fuel. Once the oil becomes fuel diluted, the viscosity and oil film protection is compromised. Once the oil viscosity has been compromised and reduced, it cannot protect the bearing surface due to the high torque loading at low RPM that the 6.2l regularly operates at. Add to this all the engine knock instances that are occuring due to Direct Injection, Low RPM/High Torque load operation. Run Regular, lower octane fuel, again, a death sentance for these engines. 11.5:1 compression ration, Low RPM/High Torque loading under normal operation is not an ideal combination for long term durability. Tow with these 6.2l's or load up the vehicles with a lot of weight, good luck, you are already dealing with 6000 lbs to start with. This all adds up to a Low Speed Pre Igntion (LSPI) party that will take out best and strongest engines over time.

At this point, I only have data for ambient temps up to around 45F, but it takes 30+ minutes of driving, in a more rural environment, not sitting idling in traffic or at traffic lights for the engine oil to reach close to the engine operating temperature. It takes at least 15 minutes of additional highway driving for the oil to reach a reasonable level where the oil temps are reasonable enough to start to cook off water vapor and fuel out of the crankcase. So depending on the driving conditons, close to 45 minutes in the cooler months to get the oil up to reasonable temperature so it have a chance at dealing with fuel and water vapor in the crankcase.

Part of this longer oil warm up time is due to the approximately 11 quarts of oil the engine, oil lines and oil cooler hold. The AFM and Auto Stop/Start do not help the oil warm up and also contribute to fuel contamination in the crankcase. Along with people starting the engine either with the keyfob Remote Start, the App or entering the vehcile to start the engine to either warm up or cool off the cabin. Allowing the engine to idle for warm up takes longer than driving. Make many short 15 minute trips in the colder months to drop kids at school, run errands, short trips to work and so forth, instant death sentance.

The transmission control module (TCM) for the 6.2l is set up for these trucks for crazy High Torque loading on the highway on a regular and reoccuing basis. Not sure why the perfect storm came together with the later model vehicles, maybe DFM at times with only 1 cylinder is then turning the entire rotating mass of the engine, and 7 cylinders are just compressing air may be part of the problem as well. I do not think there is enough overall understanding of what loading the DFM system puts on the rod bearings. With thinned out 0W20, these engines do not have a fighting chance.

 

[91RS]

Truth hurts sometimes, dealership techs are nothing more than parts changers anymore.

They plug in the computer, and replace whatever part the screen says to replace, hence why so many people are having to take their vehicles in four and five times for the same issue.

There is no troubleshooting, no understanding of what's going on, and virtually no thoughts in their head other than " rush through this task and beat book time so I can get paid more".

I've met/ hung out with a lot of dealership techs over the years as my sister was the service department manager of a Ford dealer for a little over decade. Good guys to drink with at the party for sure, but pretty much any enthusiast knows more about their cars than the dealership techs do.

Those guy are there to get paid, and its easy to justify billable hours by reading the screen and only doing exactly what it says. Even in those off-chance circumstances where they know its wrong and won't fix the problem, they'll do it anyway if that's what the screen says just to get the billable hours. In the words of the classic Metallica song it's "Sad but true".
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You are so wrong, it isn’t even funny. I have never wasted so much time reading so much incorrect information in one place as I have on your posts in this thread. I can guarantee you that you have next to no clue how these vehicles actually work. The fact that you think oil grade is determined by CAFE tells me all I need to know. You probably still think they use the Tech 2, like so many on this forum. There’s a reason the cars go to the dealer after no one else can fix them. You really think independent and chain shops (and literally every other business) don’t exist to make money? You are quite special.

 

[Antonm]

You are so wrong, it isn’t even funny. I have never wasted so much time reading so much incorrect information in one place as I have on your posts in this thread. I can guarantee you that you have next to no clue how these vehicles actually work. The fact that you think oil grade is determined by CAFE tells me all I need to know. You probably still think they use the Tech 2, like so many on this forum. There’s a reason the cars go to the dealer after no one else can fix them. You really think independent and chain shops (and literally every other business) don’t exist to make money? You are quite special.

Corporations like GM (and John Deere) make it very hard to access the vehicles computer system for a reason, and that reason is money. So often times it takes the aftermarket a few years to figure out/ reverse engineer the systems such that they can get in, and that is the one and only reason that dealers have any advantage over the independent whatsoever.

And yes , all business are in businesses for only one reason,,, to make money. And the pay structure for the mouth breathing morons at the dealerships absolutely encourages them to rush and take any and all shortcuts they can.

In case any other readers were wondering how the pay structure for dealer techs works it goes something like this.
- Each tech has an hourly rate.
- Each job has a number of billable hours assigned to it, otherwise known as "book time".
-When a tech completes job, he (or she) gets paid however many hours of their daily rate the book time called for regardless of the actual time taken.

So, if a tech gets a job with a book time of eight hours done in fours hours, they still get paid for eight hours. If they can get two of those jobs done in one day, ,,,bam,, they just got 16 hours worth of pay in one eight hour work day.

This pay structure actively encourages them to rush, take short cuts, use impact guns on everything and basically do a half-*** job because their pay literally depends on it. So its no real wonder they don't bother to actually stop and think about what's going one, because that would impact how fast they can get done and on to the next.

Is it the tech's fault,,, is it the dealership managements fault,,,, is it GM corporate's fault,,, I guess pick whichever one you want to blame, but that's the crappy system as it is. No one troubleshoots, no one thinks, and doing so would actually cause them to make less money, so they just read the screen and do what it says as fast as they possibly can.

And we wonder why it takes five trips and six months to fix anything.
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[91RS]

Oh, no! Name calling! I’m so upset now. You must be so smart. As I said, you couldn’t be more wrong about literally everything in your post.

Honest people are honest, dishonest people are dishonest. The “pay structure” (it’s called flat rate, by the way) doesn’t change that. Dealers aren’t the only ones that use flat rate anyway. Many shops do as well. All shops use impact guns. All shops want to get the most work done in one day they can.

Next.

 

[viven44]

@Antonm has a lot of truths in there however I must admit "not all techs" are probably that way. It would be very depressing if so, I would expect the early career professional to be genuinely interested in problem solving and then seasoned veterans who are just good at it and likely bored and frustated with their jobs (just like I am in my job!!!). A good manager can manage employee satisfaction, so there so many variables and hard to generalize. (his frustration in the initial post is probably from a lot of personal experience and not to be taken personally.) In my experience, the strength in going to a dealership is to address repeat issues, and if the vehicle is under warranty anyone is best advised to do that. (Even Car Wizard on YouTube doesn't work on vehicles under warranty.)

 

[viven44]

As the oil has miles put on it, the oil starts to get diluted with fuel.

Man you seem like the person I could have a friendly chat / argument so maybe I'll argue some with a different perspective. Everything I know is from wrenching on carbureted old trucks with no computer so my perspective might be different. Diagnosis using basic senses (smell, sound, sight). I have a nice scanner etc to read codes maybe do some charting and what not to see if the cats and emissions are working well and such, but in my experience I'm not good at getting to root cause that way. And I was going to chart the trans shifting for you, but my 2018 circa scanner doesn't recognize our 2024 and wants a software update.

Most recently, I helped my friend change oil on his DI engine with an excessive fuel dilution problem. 2018 Honda 1.5L which uses 0W-20 oil as well. When we drained the crankcase the oil level was a good 1" over the top and I must have drained 1-2 quarts extra. Even with that level of dilution the engine wasn't burning off the oil. If oil is simply diluted and burnt at that rate from slipping past the rings, the plugs should be fouled and there should be excessive blow-by or smoking at the tailpipe. Even if a couple of quarts are lost its shouldn't be the end of the world as the oil pickup lies low and should be plenty in the sump to prevent a catastrophic event (And oil temp would increase as well as there is less to cool and we should reach an equilibrium where the system is happy). And this I know from personal experience, I still daily and long distance drive my carbureted big blocks that really burn some oil or have leaky rear main seals, and we are talking 10W-40 oil and I have been low on oil on a consistent basis from long trips (burning a quart or 2 in a 600 mile trip on a 6 quart sump, haha!)

And why does the 6.2L have fuel dilution when the 5.3L doesn't ? Assuming they have similar high pressure DI injection pumps. Is there anything specific to the 6.2L that makes it more likely to dilute oil excessively. To me the only real difference is the call for premium fuel, maybe higher compression leading to pinging on lugging scenarios, but overall it just doesn't make sense enough yet why the engine failure reporting is higher on a 6.2L.