All gasoline engines nowadays have EGR, it is necessary to use it to pass western emissions standards.
If you can't see it, then the passage is internal or integrated into the manifolds. But it's still there.
A "cloud" of white smoke while overtaking on a new engine isn't likely an issue of coolant or oil... Otherwise your car would be losing oil and coolant at a prodigious rate.
What you described sounds suspiciously like water contamination in the fuel... (which I've experienced, with e same symptoms)... which can affect power and response on a new vehicle.
Personally I wouldn't rev any diesel at 5,000 rpm. Most likely that would be out of its torque band. If you don't get any answers from the casa why don't you try getting a used oil analysis? Baka makita in the oil kung ano yung contaminant causing the white smoke. I've heard PTT does them.
*dzl727 - kindly check your muffler / exhaust pipe by touching the inner tube with your finger. If it's damp with oil (may langis ng konti) that would most likely mean a blown gasket in your engine. This usually happens with older cars but it doesn't mean it can't happen on new ones (sana naman hindi ito yung case ng tucson mo). If itis, its still under waranty and HARI should cover the expenses.
Of course, verify your findigns sa CASA pa rin.
Hope this helps.
I highly doubt it's oil. A sudden cloud of white smoke is, 90% of the time, either a lot of water getting through the fuel filter or from the catalytic converter. If it's an oil leak via the gasket, it should happen every time you rev hard under load.
By this time, though, there's no way to tell. You should have checked the fuel system and fuel tank right after it happened.
Ang pagbalik ng comeback...