Technical Zinc sacrificial anode

If a zinc sacrificial anode is screwed into a plastic radiator drain plug, will it have its correct effect? Or must there be a metal to metal contact between the anode and the aluminum radiator?

 

There must be an electrically conductive connection between cathode and anode.

 

https://en.wikipedia.org/wiki/Galvanic_anode

For this protection to work there must be an electron pathway between the anode and the metal to be protected (e.g., a wire or direct contact) and an ion pathway between both the oxidizing agent (e.g., oxygen and water or moist soil) and the anode, and the oxidizing agent and the metal to be protected, thus forming a closed circuit; therefore simply bolting a piece of active metal such as zinc to a less active metal, such as mild steel, in air (a poor ionic conductor) will not furnish any protection.

 

Thank you.

 

I use the radiator cap that has a zinc anode attached by a spring, seems to work well.

 

^^^^RadCap

 

You can purchase zinc anodes attached to pipe plugs , the Cummins in the Power Wagon has one screwed into the water passage in the block . I have inspected it a few times in over 100K miles . It shows pitting but still not needing replacement