4. Recommending miracle cure additives
Additives have a time and a place, and with a few exceptions, they’re not going to hurt your car. That said, they’re not going to magically make it perfect again, either. If there’s a specific issue that your mechanic is trying to fix, like using fuel additive with extra detergents to avoid a more costly cleaning measure, that’s one thing. If the aim is simply to “make it run better,” you either need an explanation, or you’re the one who should be running.
5. Sucking you in the door with free tire rotation or winter inspection
Whenever you see an ad for a loss leader services, what you’re usually getting is an attempt to get you through the door, so the shop’s mechanics can go over your car and find as many things as possible that need fixing.