Blue Smoke From Exhaust
Blue smoke means the engine is burning oil. It is usually valve guides or worn rings, and it gets worse the longer you leave it.
What it feels like
- A blue-grey puff on startup that clears after a few seconds
- Smoke under hard acceleration from a stop
- Oil level dropping between changes with no visible leak
- Fouled spark plugs that keep coming back
Codes that usually produce this
No OBD-II code is recorded for this symptom yet. That does not mean nothing is wrong — it means the fix is mechanical rather than electronic, or the fault has not set a code. The checks below still apply.
Check these first, in this order
Free checks first. Nothing here costs money except the fuel you burn.
- 1
Check the oil level on the dipstick and note exactly how much it drops over 500 miles.
What you'll seeA consistent level. Losing more than a quart in 1000 miles is a real consumption problem.
- 2
Have someone watch the tailpipe while you rev the engine from idle after it sits 10 minutes.
What you'll seeA brief blue puff on the first rev points at valve guides rather than rings.
- 3
Look under the car and around the valve cover for oil wetness that could explain the loss.
What you'll seeA dry engine. Wet spots mean the oil is leaking, not burning.
Stop and get it looked at if
- The oil level drops fast enough that the low oil light comes on.
- The engine starts knocking.
- The smoke becomes constant rather than only on startup.