Chevy 6.2L L87 recall. They are checking for crank / piston DTC, if you have the code they are replacing the engine. If not, they are changing 0-20 oil to 0-40 and hoping they push you out of warranty before engine failure. So 0-20 must be for emissions not reliability? Supposedly, this is an issue with contamination and ”quality” issues with crank bearing / connecting rod / crank shaft similar to tundra’s recall.