The year of 5.3 to stay away from Chevy is the years of 2007 to 2009 as well as the 2014 to 2021 models.
The 5.3 L V8 engines that are the most problematic for Chevy vehicles or GM vehicles are found in the 2007 to 2009 models and the 2014 to 2021 models.
These years of the 5.3 engines in these Chevy vehicles are prone to Active Fuel Management and early Dynamic Fuel Management lifter failures, which lead to heavy oil consumption, collapsed lifers as well as required replacement of the camshaft.
For these engine problems and related drivetrain issues you should avoid the following models of Chevy vehicles with the 5.3 L engine, which include:
The 2007 to 2010, as the rollout of the Active Fuel Management caused massive oil consumption and lifter problems.
The 2014 to 2018 early Gen 5 engines are plagued by Active Fuel Management lifter failures.
And in addition to the engine issues, the 2014 models are also known for poor A/C condensers, blacking out infotainment screens as well as stalling.
The 2019 through 2021 models are transition year models of GM vehicles that suffered from early DFM lifter failures as well as transmission shudder, most particularly with the 8 speed automatic transmission.
When looking for a good model of Chevy or GM vehicle you should look for and consider the 1999 to 2006 Gen III, which are widely considered to have the most bulletproof and most reliable 5.3L engines and they don't have AFM/DFM, which makes then very highly reliable.
And the 2011 through 2013 models of Chevy or GM vehicles have updated valve covers and oil controls, which were used during these periods, which reduces, although did not fully eliminate the AFM risks.