I have a 1998 Mercury Villager,its been smoking I got the oil channged thinking it was because my oil was low,its sti smoking and now.I have to jump start it ,if I want to drive it...do I need an alternator or is an.oil leak?

If the smoke coming out (the back of the car exhaust) is dark grey...then you have a oil burning problem..this will cause your oil to be low sometimes quickly...if it is leaking out, sometimes oil leaks out on to exhaust under the hood, and can burn making smoke under the hood.. If the smoke is more white, then you have a head gasket problem. If you need to jump start your car, maybe you should drive to a national chain of auto parts store...they test batteries free...and test alternators free too...If you ran too low on oil, you might have a serious engine problem like a seized or nearly seized bearing, worn rings, or nearly seized motor.