None of you are understanding what I am saying. The original statement bought up in this thread was about corrosion concerns between an Al rad and a Cu block. I simply stated that their will be no corrosion cell between the Al rad and the Cu block if there is no metallic path.

As for corrosion issues within a single object, such as a radiator, that is a different story. Here the metallic path cannot be cut and the cell will set up between dissimilar segments of the same metal. You can minimize corrosion by using DW or DI water. To what extent this water remains high in resistivity is a reasonable question. I think I will take a sample of water out of my water cooling loop and measure the resistivity. It will be interesting to see how much it has changed since I first put it in.

Perhaps the best option is to use metals that are either galvanized or anodized. This will also help to minimize the problem in the first place.

Also, the use of Cathodic Protection is extremely common and any many industrial apps. I will set up a system and test it for anyone interested.

I guess I should add that I am a Corrosion Engineer by profession. This doesn't make me right, it's just that I deal with this type of thing every day. Sometimes in explaining things I forget to describe things that to me are common knowledge. So when I talk about the corrosion cell between the rad and block I am not saying anything about the corrosion cell that may be present with the rad itself.

That's all I have to say. If someone would like to know more about this topic please pm me as it isn't worth posting on these forums.

good description
why could we have not started here ?

sorry Titan151

not that it matters anymore but i bought a copper car radiator instead of the Al one. now i just need to figure out how to get all the tust /stuff out of it ( clean the inside ) what do most people do ?

I used a CLR flush - seemed to get most of the crap out (hard to tell for sure without hacking open the rad).

Swish diluted acetic acid plus a little sodium in it - the copper will be clean and bright in seconds. Rinse. Yes, that's just vinegar and a dash of salt, and extra water if you're really cheap.

Boiling it in a covered oven roasting pan will free any oils trapped in there.

just to clarify, I hope no one actually puts sodium into water in an uncontrolled environment :p
sodium chloride will do though

I remember sodium into water at school, it caused a nice satisfying explosion. :)

:D Thank you. Now excuse me while I go wander into traffic.