When you say "oil" coming out of exhaust, are you referring to the grey smoke that exits the exhaust as a result of oil getting passed the rings, or as a liquid dripping out of the exhaust tip?
If you are referring to the latter, then I concur with WDurrance, that it is indeed soot mixed with moisture. Oil in liquid form would not get that far, especially on a hot engine, unless you deliberately managed to pour it down the exhaust manifold. By that time, the catalytic converter would be so plugged up, that more serious problems would have erupted long ago!
Excessive soot however, means that you are running a too rich fuel/air mixture. Check your plugs.
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car