Aluminum Rad Glavanic Corrosion

[Vapor]

i had a long discussion about this with vapor.

Yes its true you need current for galavanic to start.
Or a presence of an electrolyte.

However i think its still too risky, since water can act as an electrolyte.
Can you goto the junk yard and look for an older chevy suburban radiator?
Those had copper cores.

Then you misunderstood what I said

The water is the electrolyte but you need to complete the circuit electrically for galvanic corrosion to occur and water cannot be both the electrolyte and the 2nd electrical pathway. Basically, as long as the copper and alu aren't touching (or connected by other metal components, such as screws), you'll be fine.

OP, you'll be fine if you run plastic/rubber tubing. (just don't report back here that you're using alu in your loop--in that sense, the world is flat here)

There are other concerns with your setup though, like freezing and condensation due to the various PC-level components (CPU block, tubing) being much colder than ambient.