1998 Plymouth Voyager white smoke when backing up

Blueish smoke is oil coming through, grayish is fuel, sometimes its so rich it gets black. White is usually coolant and it can smell like coolant. The van is under its heaviest load in reverse because of the transmission pressure required. Also the engine rocks in a different manner in reverse a gear that is used many times in an initial take off and leave a driveway or parking spot. Maybe you have coolant leaking into your engine through a warped, cracked, or bad head or gasket. It is a biggy on your 4 cylinder. If your loosing coolant, have it pressure tested. Water will run through your exhaust white also.