my ford Cmax today has started smoking from the engine bay.  Car sounds like normal no loss of power, idles fine,no water in oil,no lights on dash. Just white smoke coming from the engine bay that smells like exhaust fumes. Any ideas on what it may be?

Sounds like pre-cat exhaust.  So either a leak at the turbo or the EGR.

Sometimes it happens in the cold when all the parts contract, then they tighten up again as the engine heats up.

It's really not something you want to be breathing through the cabin vents, so if it's a constant issue, definitely worth fixing.