* Worn piston rings or valve guides: Oil can leak past worn piston rings or valve guides into the combustion chamber, burning and producing blue smoke.
* Turbocharger problems
White smoke:
* Coolant leaking into the combustion chamber : A blown head gasket, cracked cylinder head, or a warped engine block can allow coolant to enter the combustion chamber.
Black smoke:
Excessive fuel: This can be due to clogged or faulty fuel injectors, issues with the fuel pump, improper engine tuning, incorrect air-fuel mixture , over-rich fuel to air intake ratio .
