Hmmm, I just checked Nigel Calders book on marine bonding systems and sacrificial anodes. A sacrificial anode does not necessarily need to be in the "flow" just in the same solution as the other metals it is protecting. Marine engine zincs are in the raw water side of the cooling circuit, usually in the heat exchangers. Exterior zincs are simply bolted to the outside of the hull immersed in sea water. Think of a "zinc fish" commonly hung over the sides of boats for a little extra protection.

The common thing here is that the sacrificial anodes have to be bonded or electrically connected to the other metals to work! The engine zincs are "connected" because they are screwed into the engine parts. Shaft zincs and bolted to the shaft. Transom and hull zincs are connected to the bonding system in the boat that is attached to all the other metal bits of the boat, engine, thru-hulls, etc. Zinc fish are attached to the engine block with an alligator clip.

The radiator cap anode system would have to be connected to the engine block to work correctly. If installed in a metal radiator then it may be electrically connected to the chassis and therefore the engine block. On an MB there would have to be a wire to connect it to the chassis or block as the plastic expansion tank would isolate it.

Does it work? Dunno. Coolant already has additive to deal with the galvanic corrosion issues in cooling systems due to dissimilar metals being mixed in a common system. A cooling system that has proper maintenance should not need an anode. I'm betting however that if plain water was being used for coolant then this product may be beneficial.

RT

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