An electrolysis prevention device, for preventing corrosion caused by electrolysis, includes a sacrificial anode made of an active metal and an anode holder supporting the sacrificial anode. The holder is adapted to fit around the inlet connection of an engine heat exchange component, such as a radiator or heater core, in such a way as to allow for a hose to be attached overtop the device. The device may be included in an originally-manufactured engine heat exchange component or may be installed later.