copper and aluminum

[jpfletch1]

I was thinking about using a copper elbow coming off my aluminum manifold. I could not remember if these two dissimilar metals would cause and electrolysis problem. Would this be a problem with my cooling system. Thank you

[Paul F]

Do a search on 'copper aluminum' and you will find it is a very bad combination due to galvanic corrosion.

[ng8264723]

Just make a thick gasket so they don't touch and you should be fine

[jpfletch1]

So as long as they don't touch it is OK. If the two pieces were connected with a rubber hose and there was a 1/8 inch gap between them it would not be a problem.

[jpfletch1]

Do the pieces have to touch to get a reaction?

[olddog]

If there are minerals in the coolant, and the coolant conducts, then it might still cause a problem, at least in theory. In theory a gnat standing on an I beam will deflect it, and you can calculate the deflection, but does it matter in reality? I don't know the answer.

[Paul F]

Galvanic corrosion, which is what you were inquiring about (contact of different metals) requires contact between the two metals. So a space between them does prevent galvanic corrosion.

Old dog is referring to electrolysis, which is the flow of electricity between metals and fluids. Its the same process used to do plating. This is bad news as it can create leaks in your radiator and other items. Search this board for electrolysis and you will find a few threads on that topic. Here is an example - Zinc Anodes for your cooling system

[Maurice Butler]

I have had cars with copper pipe no problems, just make sure you used distilled or deionised water, anticorrission additive with or without antifreeze