GM recalls 721K trucks with 6.2L engine

[sd455dan]

The most important part of this video is around 8 minutes. How much money are we actually saving and environmental damage are we actually preventing with current EPA applications? It seems like we are stepping over a dollar to pick up a nickel.

Great video! Spot on.

 

[Hay Dude]

Everyone knew this. IMO, it’s virtue signaling.
I can see some common sense methods to reducing air pollution, and we have made unbelievable strides in the last 50 years.
However, when you get to the point of destroying the buyer’s engine to make it run cleaner, common sense is lost.

I really like the looks of the Cummins 6.7 gasser. Could be a big hit

 

[sd455dan]

Bob the Oil guy update on the test procedure and GM changing oil recommendation to 0W-40 on All new 6.2 engines as well which gets a new filler cap. This applies to new inventory vehicles on the lots as well.
Stupid 0W-20 oil... Good riddance. Will keep running the Shell T-6 5W-40 in almost everything

.

Mr. teardown ( I do Cars) just tore down another one with under 50K miles. He also owns a 6.2 in one of his vehicles.

At least GM was smart enough to run the oil pump directly off the crankshaft no submerged belts.

Only real obvious damage was one overheated main bearing, bearing shells and lots of rod bearing wear and suspect head gasket leakage. Also see what is highlighted below.
Block was rebuildable.

Interesting comment by a GM tech that has worked on many of these 6.2's and noticed a head gasket was installed Upside down...

"I work as a GM mechanic and have fixed a ton of these engines. What I know for certain is the driver's side head had previously been off and whoever reinstalled it put the head gasket on upside down. If this was done for a lifter replacement the camshaft may have been previously replaced as well. That would explain the front cover and pan having previously been off as well as the overtorqued T40 cam retainer bolts. At 13:41 there is a tab visible by the second lower head bolt from the rear of the engine. That tab should be next to the second head bolt from the front of the engine with the head gasket on correctly.

You can also see the word "front" imprinted onto the surface of the head next to the rear cylinder once you take the head off. It will run with the head gasket upside down but it blocks coolant passages to the head and leads to the head overheating badly and blowing the head gasket.

That's also why it was so badly varnished even with such a complete service history. The last one of these I fixed that had an upside down head gasket got so hot it melted the intake and warped the head 0.007". It was also getting the oil so hot it was setting oil pressure control solenoid performance codes. If this one was driven long enough the thinned out oil may have lead to the spun bearings. I've never personally seen a 2019 or 2020 L87 spin a bearing. Replaced MANY of the 2021+ engines though."

 

[ruffdog]

Well I think you need to tell us the real story now, lol.

It sounds like all the affected engines came from only one plant. The problem is how the parts were machined and the finish. The fail rate for the affected units is at 3%. I'm thinking that the problem is the surface finish on the crankshaft. Maybe some of the parts were ground in the wrong direction which leaves microscopic burrs. It would then make sense that a thicker oil may fix some engines.

"Metal removal tends to raise burrs. This is true of nearly all metal removal processes. Different processes create different types of burrs. Grinding and polishing produces burrs that are so small that we can't see or feel them but they are there and can damage bearings if the shaft surface is not generated in the proper way. Rather than "burrs", let's call what results from grinding and polishing "microscopic fuzz." This better describes what is left by these processes. This microscopic fuzz has a grain or lay to it like the hair on a dog's back. Figure 1 is an illustration depicting the lay of this fuzz on a journal. (Note: All figures are viewed from nose end of crankshaft.)"

MAHLE Aftermarket North America | MAHLE Aftermarket Inc. | Crankshaft grinding and polishing

 

[deezler]

It sounds like all the affected engines came from only one plant. The problem is how the parts were machined and the finish. The fail rate for the affected units is at 3%. I'm thinking that the problem is the surface finish on the crankshaft. Maybe some of the parts were ground in the wrong direction which leaves microscopic burrs. It would then make sense that a thicker oil may fix some engines.

Yeah I see consensus forming on crankshaft surface finish as the primary culprit here.

What I don't understand is why the surface finish on such a critical component is not measured, verified and documented. Not saying you need to measure every single piece, but at least some pieces from a particular machining batch/setup should be measured every time.
GM surely has a detailed surface finish specification for the rod and main journals on the crankshaft.

Their supplier really screwed the pooch here. I can't find who that supplier is, but GM will surely be suing them for financial recovery soon. But GM also dropped the ball on verifying Q/A.

 

[Blue Mule]

Ford specs 5W20 in the 5.0 V8 cars....UNLESS you order the "track pack" in which case they spec'd 5W50 on the exact same engine. Hmmm.... heat and stress need better viscosity? You don't say...

Ram slowly decreased viscosity on the 5.7 V8 as the years went on to appease the EPA, and it didn't take long for cam and lifter issues to start popping up.

Now GM is going to 0W40 on the 6.2 to try and save the bearings.

I've said it for years. 20 weight doesn't belong in a V8 engine.

 

[Renze]

Ram slowly decreased viscosity on the 5.7 V8 as the years went on to appease the EPA, and it didn't take long for cam and lifter issues to start popping up.

My Volvo V70 diesel was prescribed 0w/30 low friction oil from 2006 onwards. From 2007 onwards they improved cam and lifter hardening because they got cam and lifter issues within a year.
Mine is a 2007 but i run 5w/40 heavy duty anti-wear oil in it.

I've said it for years. 20 weight doesn't belong in a V8 engine.

It doesnt belong in any engine.

 

[Jstpssng]

When I was pumping gas in 1979, Gulf Oil was selling synthetic oil which leaked through the metal oil cans they had back then. I believe that it was 5-20. It sold for $3.95/ quart: a whopping amount 47 years ago.
The only car I remember using it was a Volkswagen Sciracco, which needed a quart relatively often. The owner claimed that he saved the money in gas. At 63 cents per gallon I found that hard to believe but it was his money.

 

[Snobdds]

My Toyota Land Cruiser calls for 0W-20. It's a 5.7 V8 engine. It's fine. The 5.7 is known for being bulletproof.

It's not the oil, it's the internals. The thicker oil is just a band-aid.

Again, this motor has been in GM cars and trucks for over 20 years. Roller lifter engines are not holding up to the old design of flat tappet engines. That is not the oils fault.

 

[deezler]

My Toyota Land Cruiser calls for 0W-20. It's a 5.7 V8 engine. It's fine. The 5.7 is known for being bulletproof.

It's not the oil, it's the internals. The thicker oil is just a band-aid.

Again, this motor has been in GM cars and trucks for over 20 years. Roller lifter engines are not holding up to the old design of flat tappet engines. That is not the oils fault.

No, it's not the oil's fault. But the 20W oil is making everything riskier, just a fact. OEMs are risking these kind of engine issues en masse just to try to save 0.1mpg across the fleet. Ultimately we can blame the EPA.

Frankly, getting the dimensions (bearing diameters/widths), clearances, profiles (nothing is actually flat or round), surface finishes and material compositions right for every sliding and rotating interface within an internal combustion engine is just very, very difficult. Increasing power, higher temperatures, light-weighting/downsizing, and accelerated development timelines are all conspiring to make things even more difficult.

Literally every new prototype engine program from all manufacturers right now is going through similar issues - the trick is just to catch it in time during pre-production validation testing and apply a definitive fix.

In this case, I surmise that GM passed all testing with 0W20 oil and the L87 6.2L was good to go. Then their supplier borked the surface finish on wayyyy too many crankshafts before anyone discovered the issue. There's certainly a chance the issue would not have arisen to anywhere near this level if GM spec'd 5w30 oil from the start.

 

[sd455dan]

My Toyota Land Cruiser calls for 0W-20. It's a 5.7 V8 engine. It's fine. The 5.7 is known for being bulletproof.

It's not the oil, it's the internals. The thicker oil is just a band-aid.

Again, this motor has been in GM cars and trucks for over 20 years. Roller lifter engines are not holding up to the old design of flat tappet engines. That is not the oils fault.

like much of the above GM had reports the cranks bearing surfaces were not finished to a quality finish. A micro polished crank is almost as reflective as a mirror.

Roller cams should actually hold up better minus having such a high number of roller bearing pins that can actually fail. They pulled the ZDDP out of oils and that has damaged, shortened the life of or killed many flat tappet cams and lifters of older engines. Going to thin oil was not about wear protection, it was done to eek out another % or two of MPG for Corporate fuel mileage standards and not also slowly kill Catalytic converters. Of Course jmo.

Chrysler Stellantis specced that thin weight oil for many of their engines. my sisters V6 wrangler started using a quart in 500 miles with that 5W-20 oil @ all of 36000 total miles. About ten years ago we all decided to just switch it to 5W-40 T-6 and everything improved instantly. MPG, oil use dropped to under a quart, between oil changes, and the engine runs quieter as well. More than a decade of 5W40 use and it runs great.

The Ford F 150 i picked up recently started to rattle when fully warmed up on hot days at low idle in reverse. ( $1K -not complaining) Cam phaser rattle. We dumped the factory water viscosity oil out and put in just 10W-30. Noise gone and hasn't come back. I despise that thin oil. If it was minus 40* out everyday I would probably be singing it's praises.

 

[Jstpssng]

sisters V6 wrangler started using a quart in 500 miles

They had one V6 (3.8?) which was junk, and started using oil as you describe; too often, just after the warranty ran out.

 

[Hay Dude]

They had one V6 (3.8?) which was junk, and started using oil as you describe; too often, just after the warranty ran out.

We vbought a Wrangler Rubicon new in 2020 and were advised to buy the V6. The other option was the turbo 2L. Nearly everyone told us the 2L was “crap/junk” and the V-6 was a proven reliable engine. Even a TBN member wrote a 3 paragraph warning anyone who bought the 2L turbo was a fool and the 3.8L V-6 was “bulletproof”…..
I went against conventional thinking and went with the turbo 2L. 70,000 miles later it runs like a top. Never any issues with it and it’s a spunky little bugger. It’ll hold its own with a car.
Conventional thinking and going with the crowd usually results in dissatisfaction.

 

[Dan Hunter]

Engine factory debris? Baloney.
Manufacturing debris is caught in the oil filter with the first few hundred oil passes, which happens before you even take possession from a dealer.
I read there’s a manufacturing defect in the rods, and or crankshaft.
Funny thing is, the engine code they will fail for, is , crankshaft-camshaft mis-synchronous, which isn’t a camshaft, crankshaft responsibility.

In any case, specifying a higher viscosity oil on engines not flagging crank-cam sync issues, is certainly not a fix, and it’s not a “fix” for engines not built from faulty rods, or crankshafts.
It only speaks for GM trying to band-aid, an engine design flaw, by masking it with requiring thicker oil at temperature

I saw a video from a guy that's had a few of these engines apart and what he found was the material on the piston that secures the circlip for the piston pin had broken free. I've never hear of such a thing.

 

[deezler]

I saw a video from a guy that's had a few of these engines apart and what he found was the material on the piston that secures the circlip for the piston pin had broken free. I've never hear of such a thing.

That dude is wrong though, IMO. After an engine grenades, you can imagine up many different initiation points as the cause. When a rod bearing seizes and throws the rod through the block, the piston and wrist pin suffer a lot of damage. The rod goes all catty wampus (sp?) and the circlip (wirst pin retainer) can easily get pounded out. Very, very rarely the initial site of an engine failure.

 

[sd455dan]

I Agree on the cam crank phase timing being used as determinative is kind of a Joke. More likely cam chain stretch to set that code.

For the phase to change solely by bearing wear clearance increases the pistons would most likely already be hitting the heads because of the increased bearing clearances.

Most of the engines referenced never got loose they were on the tight side and the material being stripped off seized them up. again jmo.

 

[yanmars]

Is the affected engine in any Corvettes?

 

[ruffdog]

Is the affected engine in any Corvettes?

I have heard that the affected engines were NOT in Camaros. If that is the case, I doubt they were in the Vettes either.

 

[Jstpssng]

Is the affected engine in any Corvettes?

Who would want a 6.2 in a Corvette?Raise your hand for a count.

 

[mrmikey]

The action includes the 2021-2024 Cadillac Escalade and Escalade ESV; Chevrolet Silverado 1500, Suburban, and Tahoe; and GMC Sierra 1500, Yukon, and Yukon X