Not all electrolytic caps are created equal. Some have high temperature ratings (good), higher mtf (good), higher ripple current (good), higher esr (bad). Thing is, each one of these parameters can be important, so try to find out everything you can about the caps you have, and specify a cap that is at least as good in every respect.
I buy all my electroytics from Digikey (no affiliation). Great company, tremendous inventory, next day delivery. And no surprises.