GM recalls 721K trucks with 6.2L engine

   / GM recalls 721K trucks with 6.2L engine #41  
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.
 
   / GM recalls 721K trucks with 6.2L engine #42  
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
 
   / GM recalls 721K trucks with 6.2L engine #43  
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."



 
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   / GM recalls 721K trucks with 6.2L engine #44  
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

 
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   / GM recalls 721K trucks with 6.2L engine #45  
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.
 
   / GM recalls 721K trucks with 6.2L engine #46  
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.
 
   / GM recalls 721K trucks with 6.2L engine #47  
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.
 
   / GM recalls 721K trucks with 6.2L engine #48  
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.
 
   / GM recalls 721K trucks with 6.2L engine #49  
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.
 

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