G5 LCU O-rings

[CelGen]

I have two complete Liquid Cooling Units (with two 2.5ghz processor boards each) and both have unfortunately leaked. I can confirm at least one set of processors work (the other won't make the box chime but I'm not surprised as those processors came from another G5) and I want to rebiuld one LCU.

I already drained and flushed chean the system and ordered new hoses however I don't know waht to replace the O-rings with. Since they are the source of the leak they have to be a bit larger but I don't have the slightest idea where I would be able to find such replacements and Apple certainly won't do the work for me now (and they wouldn't anyways since I bought the G5 at a recycler for $20).

Does anyone know of any suitable replacement O-rings?

Also, what ratio of coolant (would car radiator coolant be too corrosive to aluminum?) to water would work or what should I substitute the original coolant with? I don't know what happened to the coolant Apple filled one of the LCUs with but something was seriously wrong in the loop.

 

[Byrd]

That looks bloody awful! I'd check out your Yellow pages for an o-ring distributor (usually found in an industrial part of town); you could also consider using gasket silicone but I'd only do this as a last resort.

Regarding coolant, I'd use a pre-mixed radiator coolant from an auto shop. It's worked fine for me in PC watercooling adventures.

JB

 

[Osgeld]

auto coolant (mixed properly) should not effect aluminum, since a lot of cars use aluminum radiators in them

just make sure you get all that gunk out, some of it looks crystalline, which could act as a starter seed crystal in the future

 

[CelGen]

I spent a good hour just flushing the whole system so I'm preetty sure anything that was in there is not there anymore.

Anyways, I was poking around and I found a part number for an O-ring (Viton AS568A Aerospace Standard ID Number: 027) though they didn't specify for what make LCU it was for, or if it was an exact replacement or a better O-ring completely.

 

[Bunsen]

Auto suppliers are probably a good place to look for O-rings, too. Anything rated to survive life inside a car's engine bay should have no problems with the heat of a G5.

 

[Byrd]

Coke is an excellent product for "flushing" any crud out of the system - leave it overnight.

JB

 

[Mars478]

Coke is an excellent product for "flushing" any crud out of the system - leave it overnight.
JB

Diet.

This was the strategy I used to revive my Mom's iPhone.

 

[iMac600]

Auto suppliers are probably a good place to look for O-rings, too. Anything rated to survive life inside a car's engine bay should have no problems with the heat of a G5.

Agreed. When I was specialising in auto parts, I found out that O-rings aren't made to each vehicle manufacturer's specifications, but rather they just make a number of O-rings in varying thickness, diameter, etc and the auto manufacturers comply to that. So you should be able to find an aftermarket replacement that does the job just fine.

I hear these cooling blocks were made by Delphi Automotive, so you should be able to find an O-ring that meets the tolerances. What I wouldn't advise is getting the new seals from Delphi directly, as I would try to avoid reusing their parts wherever possible since they seem to be prone to leaking. I wouldn't be surprised if the blocks were manufactured pre-sealed by the time they arrived at Apple, so it's probably nothing more than a basic engine coolant inside there if Delphi was indeed the one that filled them.

Radiator and engine coolants are more than sufficient for the job, but make sure that block is sealed tight. Engine coolants conduct electricity. Go for a good brand of coolant where possible with the necessary corrosion inhibitors and so on. (I'd use a Tectaloy or Nulon coolant, but i'm not sure Nulon is as readily available) Byrd's suggestion is best, go for a pre-mixed coolant to avoid the hassle of having to mix it yourself.

Just closing, and this isn't by any means directed at the OP, just a general statement... a lot of people would advise against using car parts inside a computer, but in this case they would be the best parts for the job. Clearly this system needs parts with much higher tolerances, so it would be a pointless exercise just going to Apple or a computer parts distributor for the necessary components. Don't be afraid to think outside the box when it comes to machine upgrades and repairs.