The voltage rating displays the “not to exceed” rating, which means you can replace a 370v with a 440v but you cannot replace a 440v with a 370v. This misconception is so common that many capacitor manufactures began stamping 440v capacitors with 370/440v just to eliminate confusion.

As the temperature increases the internal pressure inside the capacitor increases. If the internal pressure becomes great enough, it can cause a breach in the capacitor, which can then cause leakage of impregnation fluid or moisture susceptibility.

AC capacitors are designed to last for many years, but eventually, they will need to be replaced. On average, an AC capacitor might last between 5-20 years.