Cap Size-

I recently used a 3300mfd Cap (6.3 volts) at its working just as good as the original 4700 (16v) cap I initailly installed on my other car. Since the voltage is so low, its not utilizing the full capacitance of the cap rated at much higher voltage, so the 3300 may acctually be better. Got it from Radio Shack, about 8 of them for a few bucks.