Engine: Troubleshoot Burning Oil
"Burning Oil" is what happens when oil gets into the cylinder and burns during combustion. The following conditions can allow oil to enter the cylinder.
Bad Valve Stem Seals
When Valve Stem Seals (VSS) are going bad, blue smoke will appear upon acceleration, after starting or after idling for a minute or two. Typically not seen during normal driving, smoke will appear as you accelerate away from stopping at a red light. The worse your seals the large the cloud of smoke. Bad seals allow oil to be sucked into the cylinder from the valve cover during the pistons down stroke. While this condition alone will not directly damage your engine burning oil will lower your gas milage and reduce power. If left uncheck the burning could also leave your engine low on oil.
Bad Piston Rings
Bad PCV Valve
Oil underneath the oil filler cap can be a sign of a clogged PCV valve.
Bad Turbo Oil seals
This condition can present with similar symptions to bad VSS. The differance is that you will find a film of oil on the inside of your intake piping.