White, Blue, or Black Exhaust Smoke

The color is the biggest clue. Answer a couple of quick questions and we’ll narrow it down and point you to the right pages — different paths for gas and diesel.

What each smoke color usually means

White — water or coolant. Thin steam that clears when warm is just condensation; thick, sweet, constant white (with coolant loss) is coolant burning. On a diesel, white is more often unburnt fuel (cold-start glow plugs, injectors, timing).
Blue / blue-gray — oil burning. Valve seals, piston rings, PCV, or turbo seals.
Black — too much fuel for the air. On gas that’s a rich-running sensor/fuel issue; on diesel it’s classic air/boost/EGR/injector over-fueling.

This tool narrows down likely causes and routes you to reference pages — it is not a definitive diagnosis. Symptoms overlap and vary by make, model, and year; always confirm with a scan tool or a qualified technician before replacing parts.