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durability of PowerMac G5 liquid cooling unit?

cb911

cb911

macrumors 601
Original poster
here's my situation. i need a PowerMac very soon, i'll most likely be buying 2nd hand. i need to use Photoshop & other apps, as well as needing lots of RAM & HD space.

so i'm looking at a Dual 2GHz minimum, but i've also been thinking that if i keep this for a few years i'll be wanting something up around Dual 2.5GHz. if i can get a 2.5 that's still in warranty, i'll purchase AppleCare (which is... 2 years, right?) so i might sell it while it's still covered. but if i got a liquid cooled G5 that was out of warranty, i was wondering what sort of costs i'd be up for if the liquid cooling unit failed? i'm guessing that it wouldn't be a cheap item... 😱

also - how do they fail. it's not like a whole pipe would blow off or anything? you'd surely notice it leaking at first, and maybe notice the temperature (hopefully) rising slowly, and be able to stop it causing major water damage?

what are people's opinions on the issue of wheather or not to buy a 2nd hand, out of warranty, liquid cooled G5. worth it?
 
I have also been wondering about this. Also, are all G5 Powermacs water cooled? or only select revisions/models? And are these water cooled G5s quieter? Sorry if those are n00b questions or too off topic, but I've been wondering.
 
cb911 said:
but if i got a liquid cooled G5 that was out of warranty, i was wondering what sort of costs i'd be up for if the liquid cooling unit failed? i'm guessing that it wouldn't be a cheap item... 😱
Click to expand...

😉

and yeah, you're absolutely right Benjamindaines. you've either got to decide to sell it before the AppleCare runs out, or be prepared to deal with any failure/repair costs.

so - anyone know how much one of those nice liquid cooling units costs?

only the Dual 2.5 and Dual 2.7 are liquid cooled. I'm guessing that the Quad is liquid cooled as well, but not 100% sure on that. as for noise... you would think that the liquid cooling would be quieter. isn't that why Apple used them instead of fans?
 
jrk07 said:
I have also been wondering about this. Also, are all G5 Powermacs water cooled? or only select revisions/models? And are these water cooled G5s quieter? Sorry if those are n00b questions or too off topic, but I've been wondering.
Click to expand...
Only 2.5GHz and higher are as well as the quad G5 are liquid cooled. I'm also pretty sure that they use some kind of oil instead of water so it might be possible that they have it so if it leaks it wont cause any damage, but I'm not sure.

so - anyone know how much one of those nice liquid cooling units costs?
Click to expand...
I also think that the cooling system is a part that cannot be replaced, they would probably just give you a new system if you are under warranty or make you buy a new one if you are outside warranty.
 
The liquid is definitely not water. It's still probably a good idea not to get it all over your computer. I've had a dual 2.5 for 1.25 years now and it's fine...oh, wait, what's that stuff leaking out...? Nah, just kidding. 😉

--Eric
 
cb911 said:
you would think that the liquid cooling would be quieter. isn't that why Apple used them instead of fans?
Click to expand...

Well I assumed the dual 2.5ghz wasn't watercooled because thats what I was using at school today, and it was getting quite loud when I was doing some pretty basic equalizer plugin stuff in Pro Tools. It was pretty silent when I was doing normal tasks, but the second it started working it was blowing pretty loud. So I guess either the non-liquid cooled ones are even louder, EEK, or the liquid cooled ones are just as loud, but are more efficient with cooling.

Also, I had always assumed liquid cooled meant water cooled, but I guess it makes sense that it is some other liquid/oil.
 
Benjamindaines said:
I also think that the cooling system is a part that cannot be replaced, they would probably just give you a new system if you are under warranty or make you buy a new one if you are outside warranty.
Click to expand...

😱

i really hope you are wrong on that one. that's a mighty expensive 'repair'! 😱

i have seen pictures of the cooling unit. it looks like it's attached to the processor (or course) but in the pics the whole unit (cooling radiators, pipes etc + processors) was out of the case? hrm... maybe someone else can shed some light on this.

well i'd at least expect that the cooling unit is very well engineered. has there even been a single incidence of a liquid cooling unit failing?

yeah i've heard that the liquid cooled units have fans as well - i guess they still need some air circulation. AFAIK the Dual-Core G5's are the way to go if you want some silent power.
 
Durability of PowerMac G5 liquid cooling unit?

Hi, I'm new to this forum and I joined so I could reply to this topic. There is a well know problem with the liquid cooling systems, but although it is an established problem, it is overall a rare occurence (I am still looking at G5s that can be affected so it hasnt put me off!). Check out this site; its very informative on G5's and indeed any mac! http://lowendmac.com/ppc/power-macintosh-g5.html

The info I get from them is basically avoid the 2003 G5's as their failure percentage is very high compared to the later macs
The liquid cooling fluid is very corrosive! - So if you have a liquid cooled G5, i'd suggest checking every once in a while to see if theres any obvious signs of leakage. I am led to believe the liquid, when its straight out of the system is GREEN - so it should be fairly obvious. It dries to form chrystals, but if leakage is detected then you should take out the liquid cooling system (which you can do) and thoroughly clean any areas affected. What i guess you could do is fit a 3rd party liquid cooling system but I'd advise looking online to see which (if any) systems can be compatible with the mac. If you have enough money then avoid the dual/quad processors altogether and go for the late 2005 dual core ones - these are cooled by fans because apple got rid of the liquid cooling (the dual core processors run cooler than the comparable dual processor versions)

I hope this helps!

p.s. despite my S/N I am still looking to buy a Powermac G5 in or close to London! So contact me if you happen to be selling one or whatever! Thanks!
 
cb911 said:
here's my situation. i need a PowerMac very soon, i'll most likely be buying 2nd hand. i need to use Photoshop & other apps, as well as needing lots of RAM & HD space.

so i'm looking at a Dual 2GHz minimum, but i've also been thinking that if i keep this for a few years i'll be wanting something up around Dual 2.5GHz. if i can get a 2.5 that's still in warranty, i'll purchase AppleCare (which is... 2 years, right?) so i might sell it while it's still covered. but if i got a liquid cooled G5 that was out of warranty, i was wondering what sort of costs i'd be up for if the liquid cooling unit failed? i'm guessing that it wouldn't be a cheap item... 😱

also - how do they fail. it's not like a whole pipe would blow off or anything? you'd surely notice it leaking at first, and maybe notice the temperature (hopefully) rising slowly, and be able to stop it causing major water damage?

what are people's opinions on the issue of wheather or not to buy a 2nd hand, out of warranty, liquid cooled G5. worth it?
Click to expand...

Well I wouldn't recomend it. My Dual 2.5 just went into Apple for an issue. Wouldn't boot, and had a slight smell of antifreeze/coolant. No visual evidence but still could possibly be the coolant system. I don't have the quote on me but this is what I remember, was for 3 parts, just to show me the prices depending on what is wrong. The processor unit, which includes the cooling system will be about $650, the logic board, just under $900 and the power supply, $150. Grand total of just under $1700 plus a $150 labor fee. So if the LCS goes it might not just be the processors that go, could be the logic board and power supply as well. Then again Apple has 2 LCS (cooling) units a Delphi and Panasonic, the 1st was in the original PMG5s including mine. Especially when Delphi has mentioned they only expect the units to last 2 years.


The coolant is a water/glycol based system, mostly distilled water. Unsure of the mixture but it has been said is either green or red.
Also the system will go to sleep if the processor goes over 108 degrees C trying to protect the system.

Most if not all Dual 2.5s should be out of warrenty by now as well, can't remember when the 2.7 came out. I am still waiting on hearing about mine but if it was a leak issue I didn't notice any coolant anywhere ever, nor a smell until it was too late.

Why don't you just go for a used Intel?
 
From what I understand the fuild they used back then is conductive so your worries are well placed.

Get some non-conductive coolant from GeekSquad or someone and you should not have to worry (it leeks but no damage done though you will want to turn off your computer and replace the coolant)

If push comes to shove then simply replace all the cables with new ones.
 
whoaaa... thread resurrection!!! 😱 😛 😀

yeah, i would definitely get an Intel Mac these days...
 
PowerOfTheG5 said:
Hi, I'm new to this forum and I joined so I could reply to this topic. There is a well know problem with the liquid cooling systems, but although it is an established problem, it is overall a rare occurence (I am still looking at G5s that can be affected so it hasnt put me off!). Check out this site; its very informative on G5's and indeed any mac! http://lowendmac.com/ppc/power-macintosh-g5.html

The info I get from them is basically avoid the 2003 G5's as their failure percentage is very high compared to the later macs
The liquid cooling fluid is very corrosive! - So if you have a liquid cooled G5, i'd suggest checking every once in a while to see if theres any obvious signs of leakage. I am led to believe the liquid, when its straight out of the system is GREEN - so it should be fairly obvious. It dries to form chrystals, but if leakage is detected then you should take out the liquid cooling system (which you can do) and thoroughly clean any areas affected. What i guess you could do is fit a 3rd party liquid cooling system but I'd advise looking online to see which (if any) systems can be compatible with the mac. If you have enough money then avoid the dual/quad processors altogether and go for the late 2005 dual core ones - these are cooled by fans because apple got rid of the liquid cooling (the dual core processors run cooler than the comparable dual processor versions)

I hope this helps!

p.s. despite my S/N I am still looking to buy a Powermac G5 in or close to London! So contact me if you happen to be selling one or whatever! Thanks!
Click to expand...

I wouldn't call it a rare problem... I just lost my 16th and 17th G5 to coolant leaks (out of a lab of 20 - 4 last year, 11 failed since April this year, then two more today).

My advice is to stay away from purchasing the liquid cooled models, which started with the 2.5 Ghz G5s. You don't want the aggravation. If the coolant systems fails, it takes a lot of parts with it (power supply, motherboard, CPUs, etc). You could be looking at an $1800 repair bill. We are covered by AppleCare, but only until the 17th of this month. Apple ended up replacing the 14 of the 15 that failed in the past, but only after repeated attempts to repair the machines, over several weeks.

(whoops, just realized this is older, but still a good topic, as I bet more of these machines are making it into the secondhand market...)
 
Hello to all.......

Endlessly fascinated by the myths and urban rumours about the fluid in LC processors........🙂

1) Forget what colour it is - that's just a dye- usually red, green or blue.

2) The coolant is about a 10 or 15% mix of Ethylene Glycol and distilled water.
(commonly used in your car as anti-freeze.)

3) Quality anti-freeze is based on Ethylene Glycol, but cheap stuff has a high content of Methanol (Meths). Hot Glycol/methanol will corrode aluminium components over time, so......

4) Closed circuit cooling systems (cars or computers) need a corrosion inhibitor to be in place - which is almost always in a commercial antifreeze - the stuff used is normally Sodium Benzoate a soft lightweight crystalline material but very soluble. This may be present at 5% by weight.

5) If you get a leak, the coolant seeps out and evaporates leaving a crystalline mess in the vicinity - this is for the most part the Sodium benzoate corrosion inhibitor re-crystallising out as the water evaporates - the green or blue colour being traces of the dye used. In the presence of Oxygen you will get some aluminium oxides forming as well (off-white slight 'Gel' appearance).

If there is a sticky 'oily' deposit in the area that'll be residues of Glycol which has quite a high boiling point. Methanol from cheap coolants will have long since evaporated as it has a much lower boiling point than water!

Cleaning up a leak ASAP is therefore important as oxygen getting into the (now empty but damp) system will cause corrosion on the Aluminium and nickel plated surfaces.

6) LC G5s had two types of LC system and if you do start to get a leak it'll be preceded by excessive untypical fan noise (frequent on/off whooshing) and probably some gurgling noises when the pump kicks in (air being circulated). The top CPU is the one to suffer the effects first and to a worse degree than the lower one as air will tend to collect at the high points. Eventually they will both 'cook'.

While each CPU does also have a thermal conduction pipe (copper) to the secondary (dry) air-cooled radiators at the back, these alone are not enough to do the job effectively without the LC system running ..... so ignoring it is therefore not a good idea.

Later LC Macs had an absorbent drip tray underneath the CPUs - but early ones did not, and as such a significant leak on the earlier machines can and will drip into the PSU underneath - which can be very hazardous.

7) Removal of the CPU block is the best way of examining for leaks - IF you feel you have the skill / time / tools to do it (static mats etc etc !). Some machines suffer from cracked or rotted connecting hoses which is fairly obvious and easy to rectify, but I have seen quite a few Delphi types where the rubber 'O' ring sandwiched between the heat exchanger housing for each CPU and the heat transfer plates starts leaking, resulting in poor cooling and a build up of 'mess' just visible in the gap between the bottom of the pump plate and the CPU boards.

This can be carefully dismantled, scrupulously cleaned and re-assembled with a high quality 'liquid gasket' compound to supplement the sealing O-ring. This is not a job to rush or tosh buckets of sealing goop around in a haphazard way...... neat and tidy does it.

Tightening of the 4 screws on each of the heat transfer plates on re-assembly should be done gradually and evenly to prevent warping of the plate or plastic housing beneath.

8) Re-priming the system - should be done with before the CPU modules are re-attached (they just make it harder / more risky if in place).

The trick is to have some freshly mixed coolant ready and some suitable sized hose (about 10mm internal dia). The Delphi system has a bleed valve at the top of the radiator covered by a plastic screw on cap. Once removed, the valve has a sprung-loaded ball inside which can be depressed with a suitable sized probe in order to release air.

A good-sized towel under the assembly is a good idea at this point.

I rigged up a 'header tank' some 2 foot above the assembly to give some head pressure and attached this to the radiator's top hose (capping off the rad's now open pipe temporarily. Depressing the ball in the bleed valve lets air out ( a bit like bleeding a CH radiator).... Rotating the assembly about a bit helps encourage air to the top of the radiator where you should keep the bleed valve as the highest point in the system (so the air collects in that high point).

I suspect that during manufacture this 'snap-on' bleed valve is attached to a rig that both evacuates the air and then releases coolant to be drawn back into the evacuated system, but that's a bit difficult to fabricate although not impossible.

Once you have the system full of coolant you'll need to re-attach the pump to radiator top house - this will inevitably lead to a small leak and a few air bubbles getting back in....... I can't advise on the best way to do this but use common sense...... keep the hose at a high point, make the transition quickly and if you don't lose more than a few drops of coolant your probably going to be OK as I can't see that the odd ml of air at the top of the system will be catastrophic. If you lose a lot of coolant - redo it and refine your technique on reconnecting.

Re-attch CPU modules with some good quality thermal paste between the dies and heat transfer plates (don't go mad!) and carefully and evenly re-tighten all the screws.

Put assembly back in the Mac, double check everything is back, fire it up and with luck you're in business.

Well - that's it, mine worked OK but I did take note of the untypical fan noise and caught it before it completely dried up and cooked the CPUs.

For the next week or so, keep an 'ear' on the machine for any recurrence of odd fan noise and pop the CPU cover plate off occasionally and have a close inspection for any further leaks.

ANY serious leaks above the PSU and you MUST power it off and remove the mains lead.

Best of luck!

😀

John H
 
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That's OK, You can take the p!ss if you want...... I'm sure the other people on the net posting queries about this problem in the last few months .... late 09 early '10...( & there are a lot), will no doubt find your comment and share your opinion??

That aside, FOOTNOTE to my above post.........

The cooling system needs to exist at +ve pressure (must be a pressure switch in the pump). At normal atmospheric pressure in the system your machine may not start fully (chimes but a bright red light appears under the CPU board).

I resolved this by using a 5ml plastic syringe (no needle reqd), such that the sprung ball in the bleed valve (Delphi system) is depressed when the syringe is pushed in..... to get a seal with the valve body and the syringe neck I put a small rubber O-ring or grommet over the syringe spout.

The sprung ball in the valve will tend to also seal the end of the syringe - so cut a fine slot across the spout to allow fluid to squirt out past the ball.

Load 5ml of coolant into the syringe, and put paper towel around the area to mop up small spills. Push syringe into valve tightly (depressing sprung ball) and squirt the 5 ml into the system. Remove quickly and repeat with a 2nd a 3rd 5ml..... that should be enough.

Dry area, clean up, replace valve cap and retry........ good chance it'll work.

(keep an eye out for further leaks of course).

JH
 
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Wow! Yet another fine example of thread necromancy!!!
😀
I love it; the OP is from 2006!
😀
Perhaps this requires a "Thread Necromancy" thread?!?!
😀
 
Help

Hi John, thanks for your post my DP 2.5ghz has issues as you have suggested - I think the O rings are leaking as I have a small amount of green crystalline build up around the processors. 🙄

I am not confident on repairing it and see your local, in another tread you mention that you repair macs, can you help? 😀

If so can you drop me a line at stevejotom@hotmail.com

Cheers Steve
 
Hi Steve,

See your email.......

----------------------------------------------------------------------------------

"Wow! Yet another fine example of thread necromancy!!!"

Absolutely...... people use their machines for years......... they continue to go wrong...... they go looking for info and help - even if it IS years after the original post!

So even if this only helps one or two people in 2010 its worth the time to post.
😉

JH
 
Thanks John

😀😀😀😀😀😀😀😀😀

Totally agree, I am posting from my now working G5 John thanks for taking the time to help me, I was struggling to find expert advice on the cooling system and your post and time to talk has saved my machine from the dustbin, thanks very much

🙂🙂🙂🙂🙂🙂🙂🙂
 
Below is a link to my Dual 2.5 G5 leak experience.

https://forums.macrumors.com/threads/155014/

The above mentioned leaky Dual 2.5 was replaced by Quad 2.5 by Apple free of charge. I still have the liquid cooled Quad 2.5 and after nearly five years the cooling system seems to be working just fine🙂 "as I knock on wood"

I am unfortunately not well versed on the reliability of Liquid Cooled Power Mac G5s beyond my own experience. I have met a couple of people who experienced leaks with their Dual 2.5 G5s, however I have never personally known of anyone with a leaking Quad G5. Sure there are scattered stories out their on the Web but from a "Brass tacks" standpoint I would not be overly concerned about the reliability of the coolant system. Hard drive failures, Power Supply Issues, and other issues would be as great or greater of a concern when talking about buying a 4-6 year old machine.

This thread should serve as testament to the reliability of the Liquid cooled G5 especially when one takes into account the relative dearth of information on the subject. I do however appreciate Spriochete's input on the matter as eventually my trusty old G5 will meet its maker. I would be very sad indeed when this does happen. Albeit at this point in time there is not much point in making a fuss over it as the G5 is following the same route of obsolescence as the old 68k based macs.
 
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