Power Mac G5 - Water Cooling Problems

Water Cooling Problems

Some 2.5 GHz dual processor and all 2.7 dual processor and 2.5 Quads were cooled by a liquid cooling system (LCS) that consisted of a radiator, coolant pump, and heat exchangers that were bolted to the processors. The cooling system was made by Delphi, a former Harrison Radiator Division of General Motors. This was a bold step for Apple, and should have allowed the use of very fast processors, giving Apple an advantage in both the horsepower and reliability race, but the LCS turned out to be subject to coolant leakage. If not caught in time, the leakage can destroy the processors, logic board, and even corrode the aluminum casing itself. While leakage was sometimes detectable by drops of green coolant in or beneath the machine, in many machines the seepage is so slight that it was almost impossible to detect without dismantling the entire computer. Later models were equipped with a Panasonic LCS which was a much more reliable system.

The LCS system fits into the case where the heat sinks would normally go, so there is no easy way to distinguish the liquid-cooled versions from the air-cooled, although most, but not all, of the LCS versions have a sticker inside warning about the possibility of leakage.