There's nothing magic in these engines that should confuse anyone who understands engines, but it seems like there's some magic required to find a competent mechanic. Most people like to think mechanics are crooks, but I don't attribute malice where incompetence better fits. Book pay nonsense only discourages competency and proper diagnosis while encouraging covering up of poor work and blaming continued problems on additional part failures where real diagnosis would have most likely found the true problem in the first place. Frankly, it's a garbage job that's harder, requires more tool purchases, continual education, less stability, and doesn't pay as well as pretty much any of the other trades. The people smart enough to be competent that don't pick a different trade are, therefore, relatively few. Unless I know I found a good mechanic, I treat them as laborers where I do the diagnosis and tell them what likely needs to be done. If it's a brief job, I still do it myself out of convenience and maybe I'm just getting older, but I realized now that I don't have to work on my cars that I don't enjoy it.