We'll pass this off to Yannick.
I was also a victim of the G5 liquid cooling problems.
This Saturday, I disassembled my machine and I made a small guide on my site.
Here is the relevant page: http://nysoyan.free.fr/Eaglefour/PowermacG5.html
Although it is in French, the page is very well documented and one can see what looks like the beginning of a premature death. Note: the page is very slow to load due to the many photos.
[translation by jwa]
