Here are 2025's most popular questions and answers from The Journal's Car Doctor column, from rotating tires to oil changes.

Everything, even the smallest of things, can affect the performance of your engine. Whether topping off your fuel tank or driving on motor oil past its expiration date, you're slowly killing your car.

Your car's engine, whether gas, diesel, or hybrid, requires sufficient oil to operate smoothly. Too much oil is bad for any engine, but the right amount offers protection against cold starts, reduces ...

Wankel rotary engines, typically but not exclusively found in Mazdas, certainly lean on the "quirkier" side of modern powertrain systems, made quirkier because most rotary-powered cars on the road ...