1995 seville has some smoking at rear of motor, is this serious

An oil leak dripping on to the exhaust, Better have that looked at, if it got bad, there is a risk of fire. Motor oil is not as flammable as , say auto tranny fluid but heated enough will burn. Ordinarily a small oil leak is nothing to be concerned with, but smoke indicates what I mean by it's getting on exhaust

First thing I can think of is a leaking valve cover dripping oil on a hot exhaust pipe. Second thing would be a leaking heater hose. What does it smell like. The liquids have a completely different smell.

oil lea I'm having from cylinders leaking around pistons. That's why I'm having my engine replaced. I had a valve job and the head gasket replaced a year ago. I was told that this is fairly common with the Northstar engine.. Get a couple of opinions before you have anything done. Good luck