Now that it's done....G5 Cooling overhaul +
Just a few notes for those that follow.... After pulling the CPU assemblies and cooling chassis, I found no! leakage at all. That's the good thing! Removing the eight screws that hold the CPU's to the cooling blocks was a little challenging. This is a late 2005 machine and was repaired at Apple in 2006 for leakage damage. They sealed it up pretty well, but the threads on the bolts that hold the cpu's tight to the cooling blocks were a mess. Would never go all the way back in. I ended up retaping the blocks for 6-32 screws and used Stainless flatheads, 1 1/4 " long. Then back nutted them on the top of the blocks so they wouldn't come loose since they didn't have any shoulders. I used a straight edge to make sure the tops of the bolts were flush with the top of the cups that they extend through. It worked out very well! I used 3/8ths x 5/8" Primochill tubing to avoid kinking...worked well also, but I did re-rout the tubing, after its "T" on the way to the pump inlet. I took it around the "A" processor ports which extended its length but made less tight bends. The Side A filter was blocked by deposits, so I cleaned that out, cleaned out the B filter and soaked the radiator in 50/50 white vinegar and water. Three flushes thru it, then overnight in a solution of it. I got the "O" rings at the neighborhood autoparts store......1 3/8ths by 1/16th if I remember right. I did learn something new....I tried to use the old processor screws, but I couldn't seat a couple of them flush with the tops of their cups. They were maybe 1/32 to 1/16ths about the tops of the cups. That's why I ended up using 6/32 bolts. That was enough to not allow the CPU connectors to seat and the machine didn't like that at all when I fired it up. So there you have it. A=40 degrees at an idle B=41 degrees idling. Machine is actually quite civil now. Fan never speeds up, Goes to sleep, stays asleep and wakes up on cue. I couldn't be happier. Oh, I did us EK ECoolant and seems to be fine. Seems that distilled water is the called for when flushing and rinsing the radiator. Any questions, I would be glad to answer. Note..this isn't an inexpensive process when you consider all the pieces. Clamps alone were $16.00. Coolant: $20 (with postage). Tubing: 5' @ $3.00 per foot. As far as I'm concerned, well worth it but be prepared to do it right.
