"Loose Nut" from Houston, Texas
Sounds like you might have a small coolant leak when the coolant system is under pressure, the coolant is dripping down on exhaust and causing the smoke. Or the tech spilled some and is on exhaust smoking. You would only notice the smoke when stopped as the wind would blow the smoke away when moving. If you still have a doubt, take to shop and have them run a pressure check in cooling system. They would put a special cap on and pressurized system. Good luck and keep us informed.