While looking for a barbed nipple adapter for the vacuum port on an aluminum intake I realized there could be a situation with dissimilar metals. Then I realized the heater hose adapter (appears to be zinced steel) and temperature sender (brass) are screwed in the aluminum and in contact with the coolant. 

I am concerned that this will cause galvanic corrosion, furthermore, the block is iron and the radiator is aluminum.

https://www.lytron.com/product-support/resource.cfm?aid=1239

The process of galvanic corrosion occurs when two different metals are touching each other in the presence of an electrolyte, a fluid that allows the flow of electrons from one metal to the other. As the process continues, one of the metals will deteriorate quickly as its electrons flow steadily to the other metal.

https://www.hunker.com/12502151/screws-compatible-with-aluminum

Whilst researching the above the following re electrolysis came to light:

https://www.northernfactory.com/knowledge/Electrolysis

I am most concerned with the temperature sender (brass in direct contact with aluminum and coolant). Has anyone found a solution or am I over thinking this? I have read on this forum the problems related to corrosion.




.150 Stroked Y-Block:327.25 ci @ >1hp per ci
 

No, you are not overthinking. It is a real problem.

Using the older GREEN COOLANT requires a yearly change (normal two year change) or you can get test strips which measure the acidity of the coolant. Another possible problem is silicants separating in the coolant and covering the temp sensor possibly leading to false readings.

When you add ALUM you have to watch over it. It (coolant) can become very acidic.

____________________________

Having grown up around boats in salt water, you're not overthinking it. There it tends to “electrical” leakage, but even if your boat isn’t plugged in, water contamination and the boat next to you might cause it. We used zinc, bolted under the hull and grounded, and also on the propellor shafts.

One on many similar products for automotive use.

https://www.amazon.com/Flex-lite-32060-Anode-Drain/dp/B001GR09S4/ref=asc_df_B001GR09S4/?tag=hyprod-20&linkCode=df0&hvadid=312151254461&hvpos=1o1&hvnetw=g&hvrand=4283299276353113058&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9033274&hvtargid=pla-570575038544&psc=1&tag=&ref=&adgrpid=62843672300&hvpone=&hvptwo=&hvadid=312151254461&hvpos=1o1&hvnetw=g&hvrand=4283299276353113058&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9033274&hvtargid=pla-570575038544

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Has anyone tried a waterless coolant?

"Benefits: Eliminates corrosion, electrolysis and reduces pump cavitation, lowers system pressure, prevents overheating."

https://www.evanscoolant.com/vehicle-types/classic-cars/



.150 Stroked Y-Block:327.25 ci @ >1hp per ci
 

Go over to the HAMB and run a search for “Evans coolant”. Three pages of threads, probably more options than you wanted.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks Miker!

The zinc is a real good idea, where do you install the anode?




.150 Stroked Y-Block:327.25 ci @ >1hp per ci
 

They make a bunch of those besides the one I picked at random. Some inside the water neck, a variety to thread in, I don’t know which work best. What I do know is you need to watch them, because when the zinc’s gone so’s the protection.

We had zincs that were good for 2-3 years in Lake Washington (winter) and salt water (summers). The boat spent 1 winter down in Tacoma for some work, and the zinc’s were gone in 6 months. The locals knew, but no one thought to tell us. Fortunately, the damage to the props and rudders wasn’t serious.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

All the major suppliers, Summit, Jegs, Macs etc sell sacrificial anodes..