BREAKING: GM is officially recalling the L87

[blanchard7684]

In the lugging regime where many perils exist (high loading, pinging), lets say 1500~2000 RPM, the 6.2L isn't particularly any torque monster by usual big block standards nor is it that much of a delta over 5.3L... especially not if its not running on all cylinders.. I have plotted the torque curves below. Its just that the smart guys who thought DFM was even worth releasing didn't realize it is really BAD to be lugging and also be not operating on all cylinders. (Random guess - Some high up in the R&D team had this cool idea so it made it out..)

View attachment 455882

Along with what @jfoj has indicated with shifting programming unloading the 5.3 to a greater degree, I've also seen that the DFM system on 5.3 in my 24 Suburban doesn't spend much time engaged and when it does it is only going to 7 or 6 cylinders. Any slight incline or wind and it downshifts and knocks it out of DFM. It takes very little applied load to disengage DFM.

So imagine that load on fewer and fewer cylinders...

Here is a plot I made from a freeway run. I engage and disengage DFM via L10/L9. L9 rpm is about 1800 rpm and l10 rpm is about 1660 rpm. This is with cruise on. You can see some small hills the throttle opens alot. this is a good reference for load. From experience I can see that if the 5.3 is at a sustained throttle percentage of 55% for greater than a few seconds it comands a downshift. So these small hills were on verge of a downshift.

You can see the moderate hill got a downshift and hit 2300 rpm (L8). Also a huge spike in throttle. I've run the same route with a decent headwind and hit L7 (2600+ RPM).

The hills I'm talking about I don't have an inclinometer reference but they are laughably small probably to what most would consider a hill.

Similar plot I've seen from a 6.2 in similar vehicle look remarkably different. Downshifting is minimal to non existent which infers a high load at low rpm. If i'm not mistaken I recall repeated instances of 100% load with no downshifting in rpm ranges at or below 1600 rpm.

Essentially what I've learned is that although the 5.3 is a heavily laden engine in a huge vehicle like the Suburban, the load seems to be "better managed" than the 6.2.

Thus the 5.3 can "get away" with running a 0w20.

(also note how many instances of a sub 14.7 afr is being recorded at constant speed of 78 mph)

 

[Vladimir2306]

The 5.3l is not put under the stress the 6.2l is by the TCM causing very high Torque loading up to 100% at 1500-1700 when cruising on the highway pulling slight to medium grades. I have not towed with my truck yet or put the vehicle in Tow mode and monitored the Torque loading yet, but I assume in Tow mode the TCM will use more engine RPM overall, i.e. downshift more frequently and into lower gears to use RPM to its advantage.

You are mistaken, the 5.3 is under even greater load than the 6.2 because it has less volume and power, thereby working with greater efficiency than the 6.2

 

[Vladimir2306]

Along with what @jfoj has indicated with shifting programming unloading the 5.3 to a greater degree, I've also seen that the DFM system on 5.3 in my 24 Suburban doesn't spend much time engaged and when it does it is only going to 7 or 6 cylinders. Any slight incline or wind and it downshifts and knocks it out of DFM. It takes very little applied load to disengage DFM.

So imagine that load on fewer and fewer cylinders...

Here is a plot I made from a freeway run. I engage and disengage DFM via L10/L9. L9 rpm is about 1800 rpm and l10 rpm is about 1660 rpm. This is with cruise on. You can see some small hills the throttle opens alot. this is a good reference for load. From experience I can see that if the 5.3 is at a sustained throttle percentage of 55% for greater than a few seconds it comands a downshift. So these small hills were on verge of a downshift.

You can see the moderate hill got a downshift and hit 2300 rpm (L8). Also a huge spike in throttle. I've run the same route with a decent headwind and hit L7 (2600+ RPM).

The hills I'm talking about I don't have an inclinometer reference but they are laughably small probably to what most would consider a hill.

View attachment 455924

Similar plot I've seen from a 6.2 in similar vehicle look remarkably different. Downshifting is minimal to non existent which infers a high load at low rpm. If i'm not mistaken I recall repeated instances of 100% load with no downshifting in rpm ranges at or below 1600 rpm.

Essentially what I've learned is that although the 5.3 is a heavily laden engine in a huge vehicle like the Suburban, the load seems to be "better managed" than the 6.2.

Thus the 5.3 can "get away" with running a 0w20.

(also note how many instances of a sub 14.7 afr is being recorded at constant speed of 78 mph)

The 6.2 engine also rarely rides the L10 on the highway, or rather, it goes at 60-70 mph. But as soon as there is a slope or headwind, the automatic transmission switches to 9th gear, or even 8th

 

[22BlackDenali]

Mine is on the list. Got the notice in the app.

Has anyone taken his truck in for this “inspection” yet? (I’m assuming it’s too soon after the notice.) Looking forward to hearing what transpired.

I called for an appointment yesterday, my dealer said they are not ready to start executing this inspection/recall because they still don't have clarity from GM of what the steps are if inspection fails.

 

[blanchard7684]

The 6.2 engine also rarely rides the L10 on the highway, or rather, it goes at 60-70 mph. But as soon as there is a slope or headwind, the automatic transmission switches to 9th gear, or even 8th

...And the data logging I have is starting from L9.

 

[Slstorch]

I am literally sitting in my 2022 Tahoe with my flashers on at a stoplight and a failed engine. I just was googling about this and found that the truck was recalled two days ago. The tow truck is on its way. I sure hope GM is going to replace this engine for free!

 

[KMeloney]

I am literally sitting in my 2022 Tahoe with my flashers on at a stoplight and a failed engine. I just was googling about this and found that the truck was recalled two days ago. The tow truck is on its way. I sure hope GM is going to replace this engine for free!

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

 

[Slstorch]

Do you know for sure

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

that it’s the engine and not the fuel unit? (Either way, sorry man!)

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

It won’t even crank with a jumper on it. It died on a slow decel. Tried to crank it and it cranked real slow and then froze. So my next question is, for people that had to replace the engine out of warranty. Is GM going to pay them back?

 

[Slstorch]

Do you know for sure

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

that it’s the engine and not the fuel unit? (Either way, sorry man!)

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

It won’t even crank with a jumper on it. It died on a slow decel. Tried to crank it and it cranked real slow and then froze. So my next question is, for people that had to replace the engine out of warranty. Is GM going to pay them back?

Do you know for sure that it’s the engine and not the fuel unit? (Either way, sorry man!)

 

[viven44]

@blanchard7684 really good info, thanks!

@Slstorch what a timing, so sorry you have to put up with this BS from GM

 

[jfoj]

The 6.2 engine also rarely rides the L10 on the highway, or rather, it goes at 60-70 mph. But as soon as there is a slope or headwind, the automatic transmission switches to 9th gear, or even 8th

My 6.2l rides on the highway in L10 ALL the time until I come to a slight grade or try to get around other vehicles. The majority of the time it will drop down to L9 unless the grade is too steep or I am heavy on the throttle to get around someone. After about 55 MPH the transmission typically shift to L10, it could shift to L10 before 55 MPH but it depends on the engine load.

This is just a random Log file that shows Engine Load and Gear, this was mostly highway driving. One note the vehicle speed was probably between 70-75 MPH for the majority of the highway cruising. Note the overall Engine Load, it is CRAZY high, this is the way the TCM is configured so the vehicle will get decent highway fuel economy. I also included just the Load graph because for some reason when I add the Transmission Gear on the graph it appears the Engine Load is shown a bit reduced. The RPM vs Load should be eye opening! Last graph is just the Current Gear.

 

[Aggie76]

This is a great thread. Like others I called my dealer and they aren't informed yet but took down my name since I had the recall notice on the app.

Dang, had a 2015 XL Denali with the 6.2L that had 180k on it that we sold/gave to our son and his family when they had their 3rd child. Loved that engine. Essentially same LS3 that is in my 2013 Corvette. Really debated between an Expedition or another XL Denali with the 6.2 when we bought our 2024 last August.

Did an oil/filter change about a month ago, wondering if I should do another change and put the 0W40 in now for peace of mind as its my wife's ride and we live pretty remote in Northern MN.

Thoughts???

 

[jfoj]

It won’t even crank with a jumper on it. It died on a slow decel. Tried to crank it and it cranked real slow and then froze. So my next question is, for people that had to replace the engine out of warranty. Is GM going to pay them back?

If the FPCM (Fuel Pump Control Module) fails the engine will crank.

If the engine locks up or spins a bearing and the engine is slow to crank and you do not almost immediately press the Start button to cancel the cranking, the starter fuse will blow, then the engine will not crank any more.

How many miles on your truck?

Make sure you fill out a NHTSA complaint even though the "Recall" if only for higher viscosity oil. At least then NHTSA starts to get a better count on how many failures are occurring.

NHTSA Vehicle Complaint Form

Sorry for your failure, good luck moving forward, I believe engines are a longer lead item at the moment, but hopefully easier to get than transmission valve bodies!

 

[Marky Dissod]

Any (GroupIV fully synthetic) 0W30 5W30 0W40 or 5W40 that's good enough for a 6.6L L8T
or a 'vette 6.2L (LT1 / LT2 / LT4 / LT5), should be good enough for an L87,
especially if you change it more frequently than the OLM says.

 

[Slstorch]

If the FPCM (Fuel Pump Control Module) fails the engine will crank.

If the engine locks up or spins a bearing and the engine is slow to crank and you do not almost immediately press the Start button to cancel the cranking, the starter fuse will blow, then the engine will not crank any more.

How many miles on your truck?

Make sure you fill out a NHTSA complaint even though the "Recall" if only for higher viscosity oil. At least then NHTSA starts to get a better count on how many failures are occurring.

NHTSA Vehicle Complaint Form

Sorry for your failure, good luck moving forward, I believe engines are a longer lead item at the moment, but hopefully easier to get than transmission valve bodies!

About 85K miles. Almost all of that highway, not towing.

 

[jfoj]

Bottom line if you want your 6.2l to live a long life, I recommend these things.

1. Run only Premium fuel, preferable Top Tier fuel or BP/Amoco with Invigorate
2. Regularly run something like Techron Total Fuel System Cleaner in the fuel tank, I run it at 50% strength full time at the moment.
3. If you have a 2024 or older model, get a Range DFM disabler
4. Run in L9 around town up to 55 MPH
5. Install a catch can and empty is every 2000-2500 miles
6. DO NOT run 0W20 engine oil, seems GM want 0W40, I run Pennzoil Ultra Platinum 0W40, it is NOT Dexos Approved, but it likely would pass Dexos testing with flying colors. Pennzoil does not want to give GM the oil formulation which is a REQUIREMENT for Dexos approval. There are other vendors that do not want to give GM their oil formulation for their higher end oils. Low Sodium is one of the major requirements of Dexos approval and Pennzoil Ultra Platinum meets this requirement.
7. Change your oil every 3000-4500 miles depending on driving conditions. Consider watching the OLM and see what 50% is in mileage and maybe you can use 50% of the OLM as the reference.
8. DO NOT drive the vehicle less than 30 minutes when the temps are below 45F. You really need to drive these vehicles a minimum of 20 minutes almost every trip. Even at 80F it take 20 minute of driving to get the engine oil up to 200F.
9. DO NOT start and allow the engine to idle for warm ups, start the engine, allow the RPM to drop to 700-800 RPM, then drive the vehicle. The oil warms up far faster when driving vs idle.
10. Check your oil every at least other fill up, which is about 1000 miles depending on how the vehicle is driven. DO NOT wait until the low oil light comes on.
11. Keep your oil level at the TOP of the dipstick hash marks. I run 9 quarts at oil change, these engines take more than 8 quarts of oil with filter, check your oil when you put 8 quarts in, you will see the oil level will be about 2/3 down the hash marks on the dipstick.
12. Get a magnetic oil drain plug and install it. It can be a good reference for iron in the crankcase, it may not solve many problems, but GM cheaped out and did away with these. My 2005 6.0l has one and it has been useful to track what is going on in the engine. my 2005 6.0l has 275,000 miles, I hope I can get at least 1/2 of this with the 6.2l??

Everyone has opinions, I have done a lot of research and data logging on my truck and I know what is going on, so the above rule are what I follow. My oil has been changed 3 times in the first 6,000 miles. I have performed oil analysis on every oil drain.

Do what you want and fell is right, but

 

[jfoj]

About 85K miles. Almost all of that highway, not towing.

It will be interesting to see if the engine failed if GM will cover it based on the current Recall for running 0W40 oil. Let us know what happens.

I keep checking the Recall status on my 2024 and still nothing. I guess when you have to process close to 1,000,000 VIN's things take some time? But I was ahead of GM on my truck after 500 miles!

 

[djnice]

In the USA, bound by CAFE MpG regulations, yes.
However:
What is the motor oil spec for L87 equipped vehicles OUTSIDE the USA (not subject to CAFE MpG testing)?
What is the motor oil spec for Corvettes with LT1, LT2, LT4, LT5?
What is the motor oil spec for L8T equipped vehicles?CAFE MpG testing very strongly induces GM to program upshifts to happen as early as possible, and to delay downshifts.
Given identical axle(s) gearing, with identical 10L80s, GM would very likely upshift the 6.2L before the 5.3L,
effectively lugging the 6.2L compared to the 5.3L in identically 'conservative' driving conditions.

Not crazy enough to suggest that the simple fix is to drive with the Tow / Haul shift schedule enabled,
even though it would lug the 6.2L less than the Normal shift schedule.

Too bad it's so hard to tune L87 vehicles ...

18 Z06 LT4 called for M1 5-30 but on track use 15-50. Then 19 LT4 said 0-40 because they just came out with that oil. It also said you could still use 5-30 and 15-50 if 0-40 is not available. They also said 18's could use 0-40. The supposed advantage was 0-40 could be street and track. I had both years Z06 and used them on the track. Point is, under higher loads, heat, etc use thicker oil. Also 21+ Z06 use the same 0-40.

 

[Scarey]

I have a 2024 mid year build and have not heard anything. I may have just jingexd it.

 

[jfoj]

Mine is a late 2024 build, 8/2024. I figure in the next few weeks it may show up as recalled. But this is really a lame recall as some of the damage may already have been done to these engines, just look at the guy that with he 2022 with 85k that likely just lost his engine today. Will be interesting to see how GM addresses his situation.

Not so worried as I am not going to let the dealer change my oil, they won't put what I want or what I am running in the crankcase. I may just piss them off and hold out on the recall so they can try and have the dealer chase me down!