I think the unfortunate situaiton is there appears to be at least 3 specific failure modes with the 5.3l and 6.2l and it is unclear if they are related in any way.
Lifter failures, often causing roller wearing, bent pushrods, twisted lifters, failure to pump back up.
Bearing failures, either main and/or rod, some may be due to the oversize lifter bores with oil starvation to the main and rod bearings, others may be due to bearing fit and/or bearing quality issues. Unclear how many of these may have been towing related.
Thrust bearing failures. Unclear if this is an oiling issue or build spec or bearing quality. Unclear how many of these may have been towing related.
All of the above could also be caused by oil pressure issues either due to the oil pump or low engine oil level. Is the 2 stage oil pump contributing to all of these problems? Fuel dilution could also be a contributing factor as well.
It would be great if the root cause(s) could be determined. Most of these failures appear to be under warranty so few 3rd parties have been able to review the damage. GM may know or hopefully knows what is going on. Either these are all related or they may be different failure modes. Asssume if GM knows what is going on they are not going to step up unless their hand is forced to take ownership and state VIN's that could be impacted.
It is really hard to be an "informed" and technically proficient owner to watch on the sidelines and hear about all of these failures. Is it really 1% or less, or are we are playing Russian Roulette with much higher percentages?
I am trying to do everything in my wheel house to hopefully eliminate these problems or reduce the chance of them occurring. This includes short Oil Change Intervals with oil analysis, magnetic oil drain plug, magnets on the oil filter which I cut open and check at each oil change, catch can and checking the oil every fill up or every other fill up. And running Preminum fuel at all times to hopefully combate Low Speed Pre-Ignition (LSPI) that could be ******* the rod bearings. Also running a DFM disable and Auto Stop/Start disabler. DMF disable is to hopefully reduce the busyness of lifters/cyliners being disabled to help eliminate some of the potential problems.
Also wondering if the 6.2l may be more prone to rod bearing issue due to the high torque at lower RPMs, some what a lugging with the 10 speed transmission?? This may be putting more stress on the rod bearings and oiling system, but who knows.
Is the 0W20 oil part of the problem? I think it is. The only reason they are using 0W20 is due to government CAFE requirments.
This is about all I can do to protect the engine and try and track if there are problems brewing. If I have an engine failure, I can pretty much eliminate anything I have control over. I hope I can have a long engine lifespan without issues, but we will see.
The safety issues of the engine randomly quiting, oil possibly being dump on the road and getting on the tires and the transmission possibly going into Park once the vehicle stops and not being able to move the vehicle without towing are all reasons to be concerned.
I really hope these failures are a low precentage and that there may be a bit more transparency about what is going on. GM went from bulletproof engines 20 years ago to these disasters due to all the government CAFE requirments.
