Sometimes diesel engines emit a white smoke while starting. The white smoke is due to unburnt fuel caused by improper heating. White exhaust can mean a number of thing ranging from, incorrect ignition timing compression problems, blown head gasket, poorly sealed piston rings, leaky valves, cracked head, cracked block, injector is stuck or not working, clogged air filter, defective waste gate such as an actuator, vacuum line etc, poor fuel quality, or low coolant temperature. I'd start with the simple stuff like the air filter if it hasn't been changed in a long time. Lots of guys continue to run big class 8 rigs when they are that way, figuring that they will eventually have to fix it anyway when something goes wrong. When it finally messed up they put it into a shop and get if fixed, chauking it up to down time. For us, that usually ends up ruining a trip, as we can't just hop into a spare rig and keep going.
โAll journeys have secret destinations of which the traveler is unaware.โ