Service function guideBlue, White and Black Exhaust Smoke

This guide teaches you to read blue, white and black exhaust smoke as a diagnostic language, tracing each colour to its likely root cause in the engine, fuel or cooling system. It is written for motorists who want to understand what their car is telling them and for working mechanics who need a structured service function to confirm the fault before quoting repairs. You will learn how the combustion and emission systems interact, how to prepare a vehicle for smoke testing, and how to run a repeatable step-by-step procedure that isolates the cause without guesswork. After finishing, you will be able to classify smoke by colour and conditions, perform the correct checks in sequence, and decide whether the fault is a simple maintenance item or a deeper mechanical failure.