YZ-Dave

We bought a 2021 Silverado with a LM2 in it in December - live in Brainerd, MN and had zero issues with the truck. MN uses blended fuel in the winter, no need for additives.

A lot of mis-information on the whole oil pump belt thing. It doesn't HAVE to be changed at 150k - the engine itself was designed to have a 150k expected life cycle, which means they targeted that mileage before the eying needed opened up. GM recommends to replace the belt at 150k, but it can run much longer. Best friend runs a dyno at the Milford proving grounds, they have LM2s with simulated 500k miles on the original belts. The transmission itself has a expected life cycle of 100k - that doesn't mean that when the odometer rolls 100k you throw on the blinker and put new clutches and bands in it on the side of the road, you run it until it gives you signs there is trouble.

Don't over think it - its 32.5% urea and the rest is distilled water. Regardless of brand.

I wonder if there is something like snow / ice keeping the grill shutters open?

Well even if a CALS goes forward and gets rewarded, you might see what, $100 - and you will still have a set of the same questionable lifters in your engine. If they did have to pay out, once they do, they are 100% off the hook. The reality is that what, 98% or more of these engines are going down the road just fine with no problem at all, and will hit 200k miles. The thing has a higher probability of being backed over at your local home improvement store by a dump truck and being totaled. GM has been dealing with the issue on these lifters for a LONG time, going back to the LS engine. The problem lies in inconsistent material problems in the metal itself and is highly inconsistent, and is impossible to know which and what lifters will fail. Should they update it - yes. But if they do that now, GM will be replacing millions of lifters in engines that won't need it. It is literally a better logistic solution for them to let them fail in the field. See the way this whole thing works with the CALS is GM will lay in the weeds, let them form their case, and will have the data to justify their decisions. There was a lawsuit being filed for Camaro, CTS, Corvette owners over starter motors going bad. Once things came out that nearly half the people on the lawsuit had modified their cars in some way, the whole thing got thrown out in court. Change the topic to the lifters - and GM can start asking for proof that all these engines had been run / serviced on time, with Dexos approved fluids, etc..... the same thing will happen. The CALS is only a good idea for the lawyers as they are the only ones who are guaranteed anything if there is a payout.

When the sun goes down - the issues are in the manufacturing of the lifters themselves. Most of the failures are in the DOD lifters (the GenV small block has actually three different lifters in it - cylinders of 1,2,7 & 8 use a traditional roller style hydraulic lifter, cylinders 3,4,5 & 6 use lifters that bleed down when the DOD system is activated, and there is a solid lifter used on the high pressure fuel pump (that is the one that makes all the noise BTW). The DOD lifters fail when they bleed down all their oil when the DOD is active, and when the system shuts off and it is time for them to fill back with oil, the pistons inside bind and dont fill with oil all the way, leading to large amounts of valve lash. Now the traditional lifters are basically the same lifters GM has used all the way thru the LS engine which had its known issues with lifters. When they fail, it was due to too tight of tolerance between the pistons and bores, where the lifters essentially go to a solid lifter. They end up tearing up the cam and or pushrods. In all honestly things like the oil you run, maintenance interval, etc.. will not make up for these issues. The GM lifters are known to just have a high failure rate. High enough that on the high end engines like the LT5 and COPO engines they use aftermarket (Johnson) lifters.

I honestly would ask - would one presume that the top of the hash marks is "Full"? They target the middle of the hash marks so there is room for oil to expand with heat - if the oil gets over the hash marks, you run the risk of creating issues with the rotating assembly creating a ton of crankcase oil vapor and the fact that the crank will "whip" in a bunch of air into the oil, emulsifying it which will actually make the oil not work nearly as well. Imagine if you would - instead of having just oil between the bearings and crank, to having 80% oil / 20% air between the bearings and crank. More oil does not mean more better - it generally leads to more problems than not enough. Along with a lot more drag on the engine, its harder to start, etc...... I own a 2018 Camaro with a LT1 (all aluminum 6.2) and a few years ago I pulled the engine out to upgrade internals. From first hand experience I can tell you that you can leave the drain plug out for a week and there still is 1.5qts of oil in the engine sitting in the oil pump, oil galleys, lifters, DOD system, etc.... there is no way to get remotely close to getting it all out. Given the fact that the GenV small blocks have so much oil injection issues in the PCV system, I honestly run my Camaro and my truck to the point where the oil just barely gets to the hash marks. On the Camaro - I went from 4-5 ounces of oil in the catch can down to maybe a teaspoon. And after the rebuild - there is zero oil / coking on the intake valves.