The 16v rated capicators in MBs are only 2.8v over the battery voltage. If a capacitor should have a working voltage of 20% more than the circut voltage,and with a fully charged battery of 13.2 volts, that would call for a capacitor with a working voltage of 15.84volts. Thats getting close to the rated voltage of 16v. It's a wonder they last as long as they do. All the ones I have replaced have been rated at 35WVDC maximum. I didn't ask, but I doubt if Radio Shack has any 100uF electrolytic capacitors rated at 16WVDC.
Bill Lewallen Lexington,Ky.Where diesels purr and turbos whirr, and we fill our cars with Green coolant.