rms,
Quote:

Hello Christoph!
I started from those links:

http://www.xlr8yourmac.com/systems/G5_CoolantLeak_Repair/G5_CoolantLeak_Repair_p1.html
https://discussions.apple.com/thread/3842869?start=0&tstart=0
http://forums.macrumors.com/showthread.php?t=1109014
http://www.saunalahti.fi/~holindho/g5-quad-v1-lcs-repair.html

Though the last link is G5 quad specific, it has interesting tips for refilling and testing the pump.
Let's speak about o-rings, the most important part: the first link report those dimensions:
- internal diameter: 1.313" --> 3,33502 cm
- outside diameter: 1.438" --> 3,65252 cm
- thickness: 1/16" --> 1,5875 mm
The second link specifies different dimension:
- internal diameter: 3,16 cm
- thickness: 2,4 mm
I ordered the second one since the fellow wich performed the refurbish on his G5 dual 2.7 wrote those o-rings are a little thicker but are ok. Ordered here:
http://simplybearings.co.uk/shop/
Obviously, those were wrong sizes.... and so I used my dremel gently and with great caution to work the hose part where o-ring would have placed.
So don't make my error: order rhe right one!
Here:
http://simplybearings.co.uk/shop/p513146/1.5mm+Section+33.5mm+Bore+VITON+Rubber+O-Rings+Allow+2-3+Days/product_info.html
or here:
http://www.ebay.it/itm/221133721374?var=520114057577&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
IMPORTANT: use the Viton because they have great resistance and durability.
I replaced only the black hose connections and left the metallic tubes since I guess you have a better heat loss with them. But if you want to follow the original project, here you are tube and anti kink coil:
http://www.ebay.it/itm/321054365551?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
http://www.ebay.it/itm/271240499066?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Tygon is one of the best cristal clear tube and have a great resistance but you can use a normal tube too.
I ordere the knurled barb to create a filler plug for coolant liquid here:
http://www.watercoolinguk.co.uk/p/Enzotech-NPH-ID38-G14-38Inch-10mm-Knurled-Barb--Inc-Blank_4324.html
I used ARCTIC COOLING MX-4 thermal paste wich I bought on ebay and Cooler Master Aquagate NC-1 (described in the first link). This coolant liquid is out of stock but I found here:
http://www.ebay.it/itm/330529814722?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Obviously, thermal paste and coolant liquid could be different according to your choice and knowledge.
T-bar for connecting tubes (I used a Y bar) is easy to find and so are the clamps and gasket sealant
Some tips:
Take care of radiator because the old coolant used by delphi leves sediments. I washed (litterally!) the radiator using white winegar and bicarbonate. I left it immerged in winegar for half an hour and then added a spoon of bicarbonate and after the reaction I left there for other ten minutes. Then I repeated process using a tube and funnel to insert bicarbonate and winegar again, just to be sure.
Pay attention to heat transfer modules http://www.xlr8yourmac.com/systems/G5_CoolantLeak_Repair/figure2.jpg
because copper heatsink is really fragile and can easily bend. Handle with care if you have to remove traces and or deposits left by leakage. Use a toothbrush after a winegar/bicarbonate treatment.
I used the gasket sealant even on pump o-ring, just to be sure. A little quantity is enough.
Once created the filler with knurled barb I started to pour the coolant liquid. Here one needs patience: pour a little quantity of coolant, move/rotate all the lcs block so that liiquid reaches all parts of it and repeat until it seems full. Close the filler and go on moving and rotating the block. Sure you will find some parts not filled (transparent tubes help so much here!). Try to move those air bubbles towards the filler and when it's done open and add coolant, close and repeat. Go on til air is gone. Place termal paste on cpu modules and mount them. Take care to mark the processor modules and place them in the original position they were before or calibration will fail!
Don't forget to calibrate the G5 once everything is mounted (I used 2.5.8 ASD dual boot disc) and place the Powermac in a not too hot place or you can occour in an error like this "Move unit to a cooler environment and retest".
I guess it's all!
Any question, I'm here.
Regards!!!

[ Edited by Jambalah 08.08.2013 - 20:19 ]