The case for sacrificial anodes in your cooling system

[flatjack9]

Originally Posted by Floyd

You can get out your organic chemistry books and your studies of inorganic chemistry (a good review of them is always recommended), however this is a simple case of electrochemistry. (dig out that book and the periodic chart).
Boats use anodes for the simple reason that they live in salt water which is a terrific electrolyte and thus highly conductive. The boat sets up a great battery between the bronze propeller and the stainless shaft. The "zinc" i.e. anode is made from zinc in this case to be the anode in this battery, thus making both the prop and shaft cathodic .
In a car cooling system where you have complete control over the liquid, none of this is necessary. If you use distilled water and modern "coolant" and change it periodically like you do for brake fluid, say every two to three years, you will have the results just like Kube.
In the old days, distilled water was never mentioned for cooling systems. Combine that with basic "antifreeze" which was ethylene glycol and a bit of lubricants for the water pump only and you have a pending disaster. Tap water, well water or roadside pond water all have enough minerals and conductance and off PH to start a real electrical party. Old timy antifreeze had nothing to stop it.
Fast forward to 21st century (actually late 20th century) and we have well developed "coolants" that have explored removing phosphates and incorporating hybrid organic acids (controlled) for corrosion protection and a million other things. Combine this with distilled water and you have a perfect liquid system that is not a home made battery, thus the electro-chemical reaction remains at zero.
Use the new stuff and only distilled water. that is why it is rated for cast iron and alloy engines. The modern-modern cars take full advantage of this in having very specific coolants for their cars. i.e. G-05; G-12;G13 ;G-40 for German cars.
You can test your cooling system with a good VOM to see if you have a voltage (low-less than 0.5 volts being generated ) between the liquid and the block/radiator. This sometimes works. If you have any tap water or old "antifreeze" in the system, drain and flush immediately and refill with a modern hi quality coolant and distilled water.
You can then forget about it until the time to change it.

I like what Floyd has to say.