Overheating and smoking

If it's smoking and that is coolant, there is still a leak. Once the system was opened to replace the gasket, you may need to manually bleed the air out. Look for a bleeder screw on the thermostat housing, or a threaded plug or sensor that can be removed.

Feel the upper radiator hose. If it is cool, coolant is not circulating and you may be seeing the steam coming from the overflow reservoir. If the air has been bled multiple times, have your mechanic perform a chemical test at the radiator to check for a leaking cylinder head gasket. That involves drawing air from the radiator, while the engine is running, through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, that liquid will turn bright yellow.

Don't forget to check that the radiator fan is turning on when the engine gets hot.