Quad G5 Liquid Cooling Pump Chugging, nasty thermal disparity between cpu's

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Level 1

15 points

Quad G5 Liquid Cooling Pump Chugging, nasty thermal disparity between cpu's

QuadG5 8.5gig ram Leopard 10.5.6: fully updated

Audible occasional chugging from liquid cooling pumps

current temperatures with 2 browsers open:

cpu A core 1: 47c
cpu A core 2: 46c
cpu B core 1: 74c
cpu B core 2: 72c

• Is regularly cleaned with compressed air
• Removed pump cowling to look for leaks - no visible leaks or evidence thereof
• Metal liquid cooling lines of bottom liquid pump are almost too hot to touch
• Metal liquid cooling lines of top liquid pump are almost cool to the touch
• cpu B remains at least 20 degrees hotter than cpu A at all times....cpu B has been hotter since purchased new.
• Internal fan noise is high when only running a single web-browser
• liquid pumps remain pinned at 3600rpm until all cpu-intensive applications are quit
• Exhaustive Hardware Test returns no faults after 3 loops
• drive diagnostics are clean
• booting from alternate OS's yeilds no difference for symptoms
• reset nvram, pram etc, set defaults via Open Firmware commands
• depressed the SMU Reset button once
• pulled the power cable for 10 seconds
• increased pump and fan noise is clearly a reaction to cpu load/temperature

Is there a repair extension on this?

if I have to buy a new liquid cooling unit, where can I buy one from?
How much do they cost?

Quad G5, Mac OS X (10.5.2), 8.5gig, 2.2 TB incl raptor raid-zero boot volume

Posted on Mar 14, 2009 1:11 PM

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Answer 1

Mar 15, 2009 1:11 PM in response to kallisti

Dear Kallisti,

Following your description there could be a problem with one of the pumps; the one with the cool pipes doesn't seem to extract the heat from the overheating (temperatures over 70˚C!) CPU B. Apart from the pump, a brave French Quad owner discovered that the cooling liquid forms cristals around and in between the very fine copper radiators at the inside of the screwed in cooling plates which are in contact with the processors, preventing the necessary flow of the fluid.

Tampering with the cooling system is a dangerous job and the problem can only be solved by Apple, and, even if the right parts (there are two different systems) are still in stock, will be a very expensive repair.

A repair extension? Are you joking? Apple still denies anything is wrong with these systems, but experiences of other owners all over the internet tell a very different story. I'm a happy owner of a normal heatpipe cooled 2 MHz G5, because I didn't trust that liquid cooling experiment for a dime when they came with it!

Best regards,
Robbert

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Answer 2

Mar 15, 2009 1:58 PM in response to Mechanic man

Hi! Sorry to interrupt but
"I'm a happy owner of a normal heatpipe cooled 2 MHz G5, because I didn't trust that liquid cooling experiment for a dime when they came with it!"

Did you do something different? I just bought a late 2005 Quad that's liquid cooled and you have me worried. Tom

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Answer 3

Mar 15, 2009 2:43 PM in response to Thomas Bryant

Dear Mr. Bryant,

I'm surprised you don't seem to be aware about the ongoing troubles with the liquid cooled Macs; its all over the internet. Coming from a B&W G3 (which I still have as a matter of fact), I always wished to own a G5, especially because I wanted to use the classic environment for years to go, knew all about this problem and then bought one of the last new 2 Mhz G5s in stock over here in The Netherlands.

The only advise I can give you is: Watch all temperatures carefully, regularly look for leakages inside (the lightning green cooling fluid is very aggressive, eventually destroys all rubber seals and hoses and after that leaks into the power supply, first eating away the steel cover protecting that device) and pray your Quad has the more reliable, later Panasonic cooling unit and will not be the next irrepearable victim.

Best regards,
Robbert

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Answer 4

Mar 15, 2009 2:57 PM in response to Mechanic man

Hi! Yes, I was aware of the problem in general but I haven't looked into how many Macs are afflicted with the problem. Posting on this board I generally run into only problems and they are usually a small percentage of total production. My quad is a late 05 model. I have a temp monitor and all the cpus are running even at 96-100 degrees F. Thanks, Tom

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Answer 5

Mar 15, 2009 3:32 PM in response to Thomas Bryant

Dear Mr. Bryant,

A Quad is always the late 2005 type G5; until October 2005 there was no 4 CPU-type G5 available.

From what I can remember the most unreliable system was the Delphi unit with two pumps. After some time Apple started to produce late 2005 G5s with Panasonic units featuring one pump and these seem to be more reliable.

But even then you should be aware of possible leakages and/or cloggings in the system. The problem is that when you see something happening there is a real chance you're already too late and full damage is done.
Some people were lucky afterwards and had their G5s repaired for free (most of them still having AppleCare), others were forced to buy a new computer after hearing the tremendous costs.
Despite denying what was happening, at a certain moment Apple apparently didn't have any spare parts left and gave their AppleCare customers brand new MacPro's as a replacement.

Nevertheless, I hope you will be able to enjoy a flawless computer for the next future.

Best regards,
Robbert

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Answer 6

kallisti Author

Level 1

15 points

Mar 15, 2009 11:11 PM in response to Mechanic man

mine has the delphi pumps

I can do the repair myself

I just need to purchase another cooling unit

of course I would prefer the panasonic LCU

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Answer 7

Mar 16, 2009 4:27 AM in response to kallisti

Hi! How do you determione which cooling unit you have? Thanks

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Answer 8

kallisti Author

Level 1

15 points

Mar 16, 2009 11:06 AM in response to Thomas Bryant

it's written right on it

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Answer 9

Mar 16, 2009 11:27 AM in response to Thomas Bryant

Dear Mr. Bryant, dear Kallisti,

As far as I know you can only be sure by removing the processor cover. If there are two black pumps it's a Delphi unit, one pump inside means you've a Panasonic. I really don't know if these units are interchangeable, I've only heard that Apple didn't remove the second sensor indicating the pump speed when using the single pump Panasonic unit and that's why you should see for yourself.

And I hope Kallisti knows what he's doing replacing the cooling system himself, providing there is still a new one available somewhere. Remember the processors are part of the unit and the computer has to be recalibrated after the procedure. And that can easely end in a disaster, because some unknown Mac technician declared in another forum the service software necessary is not free of bugs and can even destroy the motherboard.

This is as far as my knowledge reaches regarding this topic. I hope Kallisti will succeed repairing his Quad and Mr. Briant will enjoy his machine for a very long time after today.

Best regards to you both,
Robbert

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Answer 10

kallisti Author

Level 1

15 points

Mar 17, 2009 8:25 AM in response to Mechanic man

soooo

nobody knows where I can get an aftermarket liquid cooling unit for a Quad G5?

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Answer 11

DJACID

Level 1

30 points

Mar 17, 2009 12:47 PM in response to kallisti

the fans in the center are the ones that make the most noise,
but as there dont run on heat but power usage there not much you can do about them,

there is a chub tool you use which might help you out,

my g5 used to only make the chugging noise when it started up,

i have tried bunch of different ways to dispense heat but nothing really helped,

am not sure about after market solution but i seen it done, also seen a system sold recently on ebay which had processor removed and it was working fine....

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Answer 12

kallisti Author

Level 1

15 points

Mar 17, 2009 5:42 PM in response to DJACID

this isn't a fan problem

it's a dying pump problem

thanks for not reading the thread

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Answer 13

Mar 17, 2009 5:58 PM in response to kallisti

The pump/heatsink and processor are one unit and are only available that way. You want to buy a new unit, you're looking at a minimum of $1,500. http://welovemacs.com/appomacg5qu218.html

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Answer 14

kallisti Author

Level 1

15 points

Mar 18, 2009 10:28 AM in response to Steve Boultbee

that is insane 😟

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Answer 15

andymac

Level 1

40 points

Mar 24, 2009 9:43 AM in response to kallisti

Hi Folks,

Have only just read through this thread. My PowerMac dual 2.5 suffered a leaking cooling pump a few weeks ago & I'm in the process of fixing it. Mine is a late 2004 model and is fitted with a single Delphi pump. The leak has come from the base of the pump (looks like a failed 'o' ring). The Delphi pump is the same as a Swiftech 350 or a Laing pump - easily available on the net for around £40 GBP. The pump comes with 3 cables (2 x power & 1 x rpm) - from this thread I see that my Mac has 4 pins on the pump cable, so this must include the redundant 2nd pump speed sensor..

After reading through this, I've a couple of Q's:
- Does anyone know which of the the 4 wires does what on the Mac pump connector block ?
- Do I need to run the calibration software after I've put eberything back together ? If so, where can I get it ?

Kallisti,
I agree with your sentiments regarding the massive cost of buying a new LCS - that's why I've gone for the repair myself. It's not complicated, and the cooling system is a lot simpler than some of those fitted to custom PC's.

Cheers,
Andy

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