Most MB's will run 100C or a little higher in warm humid weather with the AC engaging.
A temp of 112C is NOT overheating, unless your coolant/H2O is WAY off.
I agree with many of the above comments. The fan turn-on MIGHT be a problem, but you've got to approach this as a complete diagnostic of your cooling system. I would be especially concerned about the "smoke" that occured at such a low temp.
1998 C230 "Black Betty"