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PowermacG5 2005 Single Pump Delphi - possibly broken pump

T

theodor12

macrumors newbie
Original poster
Dec 2, 2020
20
2
Hello, so I have a PowermacG5 single pump LCS and it suddenly stopped working. After I had to disassamble the machine to clean it from years of dust, it looks like the pump decided to stop working. It just doesn´t seem to turn on at all. And because of that, the system immediately (after 7-10 seconds) OVERTEMP and CHECKSTOPs.

And when I was looking on other forums, everyone said that their Powermac started OVERTEMPing after 4-5 minutes. And I think, that it is impossible for my Powermac to have so high temperature, to OVERTEMP immediately after 7-10 seconds after pressing the power button. And that is why susspect the pump.

I just think, that the Powermac has to know, that the pump isn´t turning on/working and because of it OVERTEMPs immediately even when the CPUs don´t have the chance to reach so high temperature to OVERTEMP after so little time after turning it on.

Or if you know a little more, please prove me wrong and there is wrong something else.
So please, think about my theory and help me. :)
 
Hi !

you mention pump is not working ? Do you see anything leaking out like coolant ? If not, then it could be the hose is clogged. I have a single pump G5 Quad and it work since 2009 when I buy it. I suspect pump is clogged or you have leak and coolant not in pump anymore as it dry up.
 
theodor12 said:
Hello, so I have a PowermacG5 single pump LCS and it suddenly stopped working. After I had to disassamble the machine to clean it from years of dust, it looks like the pump decided to stop working. It just doesn´t seem to turn on at all. And because of that, the system immediately (after 7-10 seconds) OVERTEMP and CHECKSTOPs.

And when I was looking on other forums, everyone said that their Powermac started OVERTEMPing after 4-5 minutes. And I think, that it is impossible for my Powermac to have so high temperature, to OVERTEMP immediately after 7-10 seconds after pressing the power button. And that is why susspect the pump.

I just think, that the Powermac has to know, that the pump isn´t turning on/working and because of it OVERTEMPs immediately even when the CPUs don´t have the chance to reach so high temperature to OVERTEMP after so little time after turning it on.

Or if you know a little more, please prove me wrong and there is wrong something else.
So please, think about my theory and help me. :)
Click to expand...

When you disassembled and cleaned your internal case and components, you made sure to clean out the dried, original thermal paste and add fresh thermal paste to the CPU-heatsink plates and memory controller heatsinks, yes?
 
Macbookprodude said:
Hi !

you mention pump is not working ? Do you see anything leaking out like coolant ? If not, then it could be the hose is clogged. I have a single pump G5 Quad and it work since 2009 when I buy it. I suspect pump is clogged or you have leak and coolant not in pump anymore as it dry up.
Click to expand...
Hi,
No, there is no coolant leak. I have never seen that in my Powermac. I’m sure it has never leaked.
It is possible that it is clogged. Because yesterday the pump at least started turning on with the system. So I’m sure it’s working. But it sounds like motorbike. It’s really loud and doesn’t sound healthy. It sounds like it’s running without any coolant. So it could very well be clogged.
 
B S Magnet said:
When you disassembled and cleaned your internal case and components, you made sure to clean out the dried, original thermal paste and add fresh thermal paste to the CPU-heatsink plates and memory controller heatsinks, yes?
Click to expand...
Yes, I’m sure that there is fresh thermal paste on both cpus. But I didn’t change anything on any memmory controller. Where is the memmory controller located?
 
theodor12 said:
Yes, I’m sure that there is fresh thermal paste on both cpus. But I didn’t change anything on any memmory controller. Where is the memmory controller located?
Click to expand...

It’s located on the backside of the main logic board. To get at it, you must first remove the main logic board.

If you didn’t replace all the thermal paste yourself, then it is “better safe than sorry” move to clean out all existing thermal paste and replace it yourself with fresh paste, just so that you can a) be sure it’s done and b) put a date on when the last thermal paste was applied.

And yes, even after all this, it is still possible that your coolant pump may not be powering up due to motor failure, but it’s nevertheless good practice to eliminate all the variables, one at a time, as you pinpoint the cause of your troubles.
 
Melchieor said:
I honestly suggest air cooling your G5. I aircooled two of my quad G5s and haven't had a problem since. https://forums.macrumors.com/threads/quad-g5-air-cooled-dxf-included.2229488/
Click to expand...

That link provides a really good breakdown of an air-cooled conversion for the multi-core G5s, but unless you or another person is offering the specialized tools and services needed for the conversion, such as the wire-cutting edm or similar precision machining equipment, then this advice isn’t going to be very helpful for this topic’s poster’s situation.
 
B S Magnet said:
That link provides a really good breakdown of an air-cooled conversion for the multi-core G5s, but unless you or another person is offering the specialized tools and services needed for the conversion, such as the wire-cutting edm or similar precision machining equipment, then this advice isn’t going to be very helpful for this topic’s poster’s situation.
Click to expand...
That’s not necessary. Just buy two of these . https://www.ebay.com/itm/Apple-Powe...2349624.m46890.l49286&mkrid=711-127632-2357-0 The trick is getting the screws in. I just used the same black screws that comes on each cpu board . Make sure it’s tight and use good thermal paste.
 
If your LCS utilizes the fully enclosed cooper cooling blocks as opposed to the o-ring dependent heat transfer module, the issue is most likely that sediments in the coolant have clogged the cooper blocks. Disassembly isn't fun however once fixed, should give you 15 more years of service.
 
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