Smoke is unburned fuel, coolant, or oil leaving the exhaust. The colour narrows the system. It does not name the part by itself.
A field reading
- Black under load: not enough air, or more fuel than the air can burn. Check the air filter, intake leaks, the turbo, and then fuel delivery.
- White on a cold start that clears: often normal. White that stays, with a sweet smell or coolant loss: head gasket, liner, or a cooler.
- Blue or grey: oil. Look at the turbo seals, valve guides, and ring sealing.
Note whether it happens at start, at idle, or only when the machine is working. That timing matters as much as the colour.
With the engine serial and that description, the parts list gets much shorter before anyone opens the engine.