I've owned a lot of old cars in my time, so the occasional dark puddle or stain from a fluid leak on my driveway has been an all-too-common sight. My thought process is the same every time -– do I ...

Q: I have a couple of friends: one swears by oil additives – especially the brand Lucas – and another claims an oil additive ruined his truck engine. What is your take on oil additives? A: Some oil ...