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
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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."