BREAKING: GM is officially recalling the L87

[viven44]

Millions of current gen 5.3's are out there without these issues running on 0W20. This is not an oil issue, but a manufacturing defect. 0W40 looks to be nothing more than a holy grail fix to marginal engines. Corvettes use 0W40 because of the high rpm's and possible track use.

This post by @blanchard7684 is a very good read and says higher rpms would favor lower viscosity and higher loads would favor higher viscosity...

A 6-sigma manufacturing defect over the course of 3-4 years ? Possible but on the sloppy side of things certainly for a manufacturer that has been building internal combustion engines for over 100 years. Be easier to reconcile as a poor design specification that put the "target" too darn close to the spec limits and the smallest of manufacturing variation would create a "defect" ?

For what its worth I did some Rockauto look-up on 2021s and found that most of the oil viscosity dimension specifying bottom-end components below are shared between the Corvette and the Truck 6.2s

Rod bearings
Rod bolts
Main bearings
Main bolts
Pistons
Piston rings

Crankshafts are different so its possible they messed that up on the trucks

Corvette - GM GENUINE 12705121
Truck - GM GENUINE 12710954

Be real nice if GM can do it like the old days where the oil type wasn't specified as just 1 option and a chart was provided based on ambient and use conditions and "when Trucks were used as Trucks"

 

[Silverado4x4]

Millions of current gen 5.3's are out there without these issues running on 0W20. This is not an oil issue, but a manufacturing defect. 0W40 looks to be nothing more than a holy grail fix to marginal engines. Corvettes use 0W40 because of the high rpm's and possible track use.

Exactly, 0W40 is just pushing out the inevitable. Oil is not going to fix that issue.

 

[2024 White Tahoe]

This post by @blanchard7684 is a very good read and says higher rpms would favor lower viscosity and higher loads would favor higher viscosity...

A 6-sigma manufacturing defect over the course of 3-4 years ? Possible but on the sloppy side of things certainly for a manufacturer that has been building internal combustion engines for over 100 years. Be easier to reconcile as a poor design specification that put the "target" too darn close to the spec limits and the smallest of manufacturing variation would create a "defect" ?

For what its worth I did some Rockauto look-up on 2021s and found that most of the oil viscosity dimension specifying bottom-end components below are shared between the Corvette and the Truck 6.2s

Rod bearings
Rod bolts
Main bearings
Main bolts
Pistons
Piston rings

Crankshafts are different so its possible they messed that up on the trucks

Corvette - GM GENUINE 12705121
Truck - GM GENUINE 12710954

Be real nice if GM can do it like the old days where the oil type wasn't specified as just 1 option and a chart was provided based on ambient and use conditions and "when Trucks were used as Trucks"

When I started my first job while in school in 1968 at the local “filling station” (full-service gas station), there were two oils sold for gasoline vehicles and light trucks: 30-weight and 40-weight.

It was common for gasoline engines to use oil and we checked the level with each gas purchase. We sold many quarts of oil due to low engine oil level.

 

[vcode]

This post by @blanchard7684 is a very good read and says higher rpms would favor lower viscosity and higher loads would favor higher viscosity...

A 6-sigma manufacturing defect over the course of 3-4 years ? Possible but on the sloppy side of things certainly for a manufacturer that has been building internal combustion engines for over 100 years. Be easier to reconcile as a poor design specification that put the "target" too darn close to the spec limits and the smallest of manufacturing variation would create a "defect" ?

For what its worth I did some Rockauto look-up on 2021s and found that most of the oil viscosity dimension specifying bottom-end components below are shared between the Corvette and the Truck 6.2s

Rod bearings
Rod bolts
Main bearings
Main bolts
Pistons
Piston rings

Crankshafts are different so its possible they messed that up on the trucks

Corvette - GM GENUINE 12705121
Truck - GM GENUINE 12710954

Be real nice if GM can do it like the old days where the oil type wasn't specified as just 1 option and a chart was provided based on ambient and use conditions and "when Trucks were used as Trucks"

The Corvette track prep guide allows for 15W-50 to be used during the track, but must be changed back to 0W-40 afterwards. Soooo... Again this is a mfg problem, not an oil problem.

 

[viven44]

The Corvette track prep guide allows for 15W-50 to be used during the track, but must be changed back to 0W-40 afterwards. Soooo... Again this is a mfg problem, not an oil problem.

MFG Problem because it was manufactured for 0W-40 usage ? If that Reddit post is true, then virtually every 6.2L manufactured for trucks between 2021-2024 is going to be replaced !! Manufacturing problems are seldom that gross but design problems can be.

Sorry I'm not trying to argue with you or anything, just don't have the facts from GM yet. I wish I could grab a crank from the 6.2L from the Trucks and Corvettes from that time period and plastigage both with the same bearings and see if there are clearance differences....

Where I am wanting to go with this is... if they did apply a fix that altered clearances after June 2024, and truly re-specified the 6.2L crank journals for 0W-20, then folks like @jfoj should be mindful of that before applying 0W-40.

 

[DuraYuk]

You would think so, its a double edged sword and I must admit the very best of us could wait until the last moment to see if we can get lucky... recall too early and you can risk brand reputation over something really small, and recall too late and you can risk brand reputation as well.... here this time, I'd say it was a bit too late for GM's own good.

"On January 16, 2025, GM opened a product investigation following notification from NHTSA of its investigation into alleged engine failures in GM vehicles equipped with the L87 V8 engine. GM closed three prior investigations into this condition in February 2022, June 2023, and July 2024 based on the available safety field information."

"A series of crankshaft and connecting rod manufacturing improvements implemented on or before June 1, 2024, addressed contamination and quality issues."

GM knew something was wrong since about 2022, but they likely waited it out to see if the "early field failures" already happened and if the "intrinsic failure rate" would be low enough to just warranty as needed... but it does look like they found a 'fix' and still chose to be quiet.... but when the NHTSA investigation opened up the cat was out of the bag.

This isn't like most other recalls as it took them 4 different investigations to close on the root cause, and to be honest do we really think they have actually fixed the problem now?

The FAQs on this recall said the 0W-40 oil will offer an "increased further level of protection"... and given that no one has explained to me yet why the 6.2s on the truck can live with 0W-20 when the C7 corvettes need the 0W-40, I am still very perplexed. Are the bearing clearances different ? A truck weighs twice as much as a corvette so the engine is more likely to be lugged. The only differences I know of between the truck and the corvette 6.2s is in the top end (intake manifold, maybe cam, lifters, valve springs).

Just stop man.
A corvette motor and the truck engine is different. It's that simple.

You have been parading about the oil for forever. Were you the guy saying you need to overfill the oil by a whole quart? Sheesh

You are thinking too much.

 

[viven44]

You have been parading about the oil for forever. Were you the guy saying you need to overfill the oil by a whole quart? Sheesh

Thats not me... in fact I have been advocating against that. You seem to have trouble following who said what.

Thinking too much ? Yes that has been a curse for some of us in the 'spectrum' but I try to keep things as simple as possible personally else life would be difficult... I am still quite happy driving my 78 and 84 pickup. No computers, well proven technology. If everyone in my family would still drive the old trucks we wouldn't be involved in all this BS.

A corvette motor and the truck engine is different. It's that simple.

Yes in the top end, at least for this engine model, but the bottom end is the same. And trucks are not the trucks they used to be... have you seen at what RPM said truck engine makes peak torque ? Sorry man but some of us are wired in a manner where "in god we trust, all others must bring data".

 

[vcode]

MFG Problem because it was manufactured for 0W-40 usage ? If that Reddit post is true, then virtually every 6.2L manufactured for trucks between 2021-2024 is going to be replaced !! Manufacturing problems are seldom that gross but design problems can be.

Sorry I'm not trying to argue with you or anything, just don't have the facts from GM yet. I wish I could grab a crank from the 6.2L from the Trucks and Corvettes from that time period and plastigage both with the same bearings and see if there are clearance differences....

Where I am wanting to go with this is... if they did apply a fix that altered clearances after June 2024, and truly re-specified the 6.2L crank journals for 0W-20, then folks like @jfoj should be mindful of that before applying 0W-40.

From GM Authority..... The investigation uncovered two main culprits behind the failures – first, there was evidence of rod-bearing damage resulting from sediment contamination in the crankshaft oil galleries and connecting rods. Second, some crankshafts produced during this period exhibited out-of-spec dimensions and inadequate surface finishes. These combined flaws can lead to accelerated bearing wear, which in turn may cause severe engine damage or outright failure....... Again, these are mfg problems. Debris in the oil galleries and out of spec cranks can ruin any engine no matter what oil is used. I think 0W20 is just fine for an engine with good parts, evidenced by the lack of issues with the 5.3's. I doubt they altered any clearances. I just think they are ensuring that crappy parts are not being used. My 2 cents.

 

[Marky Dissod]

Corvette "motor" and truck "engine"? Yes they are clearly different ... and if you remember from the 60s, the 2 have shared engines many times.
Just go back in time and see how many times the oil specifications have diverged.

Actually tried comparing the specifications of the LT1 vs the L87 on several different websites,
like

LT1 6.2L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

Learn all about the Gen 5 6.2L LT1 engine, including LT1 horsepower, LT1 engine specs, history and much more!

www.onallcylinders.com

L86 6.2L EcoTec3 Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More - OnAllCylinders

The L86 is a Gen. 5, 6.2L, small-block engine powering 2014-present GM trucks and SUVs. They are known as the EcoTec3 6.2L engines. These engines use a longer intake runner than its …

www.onallcylinders.com

So far, only differences I can find are:
6600 vs 6000 redline (which can be as simple as a difference in the GM OE tune)
different intake manifolds for 'vette vs trucks / SUVs

To be clear: I can't find any other differences in the hardware specs.
Nearly everything is the same, including the pistons, cam, heads, valvetrain,
static (and thus dynamic) compression (again, possible differences in the GM OE tunes)

The good news IS the bad news here, I guess?:
An L87 IS an LT1, except with a different intake manifold and a slightly lower redline.

 

[DuraYuk]

Thats not me... in fact I have been advocating against that. You seem to have trouble following who said what.

Thinking too much ? Yes that has been a curse for some of us in the 'spectrum' but I try to keep things as simple as possible personally else life would be difficult... I am still quite happy driving my 78 and 84 pickup. No computers, well proven technology. If everyone in my family would still drive the old trucks we wouldn't be involved in all this BS.



Yes in the top end, at least for this engine model, but the bottom end is the same. And trucks are not the trucks they used to be... have you seen at what RPM where said truck engine makes peak torque ? Sorry man but some of us are wired in a manner where "in god we trust, all others must bring data".

Yeah its 43 pages of nonsense. In the beginning we said it wasn't oil and here we are 40 pages later lmao.