The case of the leaky Mac: Power Mac G5 (liquid-cooled) coolant leaks

Where's the little Dutch boy when you need him? In Late 2006, we reported on the leaking of liquid coolant from some thusly cooled Power Mac G5s, in some cases causing severe damage to internal components including the logic board, power supply and more. The resulting lack of cooling liquid can also lead to processor overheating, resultant in sudden shutdowns and other erratic behavior.

The initial problems were reported with early liquid-cooled Power Mac G5s that apparently did not feature a sealed cooling system. However, we're now receiving reports of the issue implicating the latest revisions of dual-processor G5s. One reader writes:

"I have a lab of 17 Dual 2.7Ghz G5s that are all now leaking their coolant- all at once. A significant number are dead in the water and the rest are just holding on right now. Symptoms are wide-ranged but will include fans spinning wildly, machines shutting down when they heat up, greenish liquid leaking from the case, and if you are able to look, crystalized liquid forming where the CPU meets the heatsink as well as corrosion of all the metal surrounding the CPU module. Eventually, the machines just stop working altogether necessitating a replacement of CPU, Logic Board, Power Supply, and two smaller parts. In one case the power supply started to shoot off black smoke and then died.

"As of yet, Apple has been fairly unresponsive in fixing or replacing them and I am now working on making this more public. I am curious to know if any other people are having this problem. I know of 3 other cases outside our own lab here. The machines in our lab were the first of the dual 2.7s- they were bought right when the came out."

In some cases, the issue is first indicated by a distinct clicking noise -- or loud crackle -- emanated from the G5 housing.

Unfortunately, many G5s are failing outside of standard warranty range, necessitating costly repairs. Some repair prices for afflicted units are running upwards of US$1800 -- nearly the price of a new Mac Pro.

If you discover a coolant leak or apparent coolant leak, you should immediately discontinue use of your Power Mac G5 and seek assistance. As noted in this data safety sheet for the G5's liquid cooling system, there are some potentially adverse health effects that can be caused by the cooling substance if handled.

Feedback? Late-breakers@macfixit.com.

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