PDA

View Full Version : PM G5 2.5ghz Quad fan issues




Amigaz
Feb 14, 2011, 03:18 PM
Recently aquired a very nice PM G5 2.5ghz Quad, the machine works perfectly except that the fans speed up to over 2000rpm very quickly (quite loud noise) from it's "idle" 900-1000rpm when I put on some very slight load on the cpu's...and the temp difference between the two CPU's is around 20-25C which isa kind of worrying

I've vacumed the heatsinks from the front side by removing the CPU intake fan assembly, reset the PMU, ran the apple diag DVD which reported no errors and did the thermal calibration but still the temps differ between the CPU's and the fans go quite loud without me pushing the machine.

iStat reports both liquid cooling pumps operating at the same speed.

Any idea's?



VanneDC
Feb 14, 2011, 03:47 PM
Yeah, that's a little worrying...

Does Istat report the same pump Rpm for both CPUs? Any churning sounds? Sounds like you've looked for leaks?

666sheep
Feb 14, 2011, 04:20 PM
..and the temp difference between the two CPU's is around 20-25C which isa kind of worrying

Any idea's?

Sounds like it's time to rebuild your LCS. This kind of difference in CPUs temps indicates that one CPU gets not enough cooling. It may be pump that's going bad, for instance. It works, but it isn't that efficient as it should be (due to its mechanical wear).

Amigaz
Feb 14, 2011, 11:40 PM
Yeah, that's a little worrying...

Does Istat report the same pump Rpm for both CPUs? Any churning sounds? Sounds like you've looked for leaks?

Yep, same RPM for both pumps and no churning sounds

No leaks whatsoever

Amigaz
Feb 14, 2011, 11:41 PM
Sounds like it's time to rebuild your LCS. This kind of difference in CPUs temps indicates that one CPU gets not enough cooling. It may be pump that's going bad, for instance. It works, but it isn't that efficient as it should be (due to its mechanical wear).

Does Apple still have spare parts for the LCS?

MacHamster68
Feb 15, 2011, 02:42 AM
could it not be as simple as dried out thermal compound or some like to call it thermal paste , anyway it cannot harm to rebuild the whole lcs system with new parts , with many starting leaking far earlier , so even if yours does not leak at the moment it seems advisable to do that now the G5 quad is 5 years old as a precaution, just because when it starts leaking its often to late and like in cars its advisable to change the coolant in the lcs every couple years anyway ....i mean better safe then sorry , and yes to my knowledge you can still get the parts

here a good how to guide
http://www.xlr8yourmac.com/systems/G5_CoolantLeak_Repair/G5_CoolantLeak_Repair_p1.html#storytop

Amigaz
Feb 15, 2011, 02:34 PM
could it not be as simple as dried out thermal compound or some like to call it thermal paste , anyway it cannot harm to rebuild the whole lcs system with new parts , with many starting leaking far earlier , so even if yours does not leak at the moment it seems advisable to do that now the G5 quad is 5 years old as a precaution, just because when it starts leaking its often to late and like in cars its advisable to change the coolant in the lcs every couple years anyway ....i mean better safe then sorry , and yes to my knowledge you can still get the parts

here a good how to guide
http://www.xlr8yourmac.com/systems/G5_CoolantLeak_Repair/G5_CoolantLeak_Repair_p1.html#storytop

Yeah, I'm going to remove, dismantle + inspects the cooling system

Still haven't figured out how to get in touch with Apple to order LCS parts, maybe I should contact my local Apple service center to get info on where to get spare parts?

I've attached pics from iStat with the machine in idle and with a slight load

Idle:

http://thumbnails6.imagebam.com/11967/ae24b5119663597.jpg (http://www.imagebam.com/image/ae24b5119663597)

Slight (tiny) load:

http://thumbnails23.imagebam.com/11967/f688bb119663601.jpg (http://www.imagebam.com/image/f688bb119663601)