I get a whole lot of White Smoke when I drive my car now. It almsot just pours out the back. When I rev up. What would the white smoke be. I heard it would be a bad headgasket and coolant leaking in my cylinders. But I noticed that it looks like there is a leak on the outside of the headgasket, like oil and water mixed. What color would the smoke be if I had bad Piston rings?