If white smoke comes out of the exhaust (full load)
Air in fuel supply system.
Wrong fuel quality or contaminated fuel.
Check fuel. Drain and flush fuel tank. Replace with new fuel.
Faulty injector/injection pump.
Check, replace if required.
Vapors condensing at the exhaust for very low ambient
temperature
If you find burnt oil traces at the exhaust.
Check, Repair / Replace .
Excessive wear of cylinder / piston, piston rings.
Check compression; refurbish engine.