Did you really mean to say, "on the exhaust pipe"? That would imply oil is dripping onto it from the engine, and that would indeed be caused by a leaking seal, most commonly a valve cover gasket. You'll see and smell the smoke, but it won't be blue.
If you're seeing blue smoke from the tail pipe, that is a sign of burning oil in the engine. Typical causes are worn valve guide seals, worn piston rings, an inoperative PCV system, and oil that has been diluted with gas.
Saturday, January 21st, 2017 AT 2:29 PM