Originally Posted by Chris155
Every single GTA engine I have worked on has had a plastic impellor. Jamie may be right.....
Interestingly, Jamie's article in the AROC mag this month is about the V6 engines, and he says "By the time they developed the 24V engine they had eliminated most of the issues except one which was due to penny pinching on the impeller for the water pump which, on some models, they made of plastic". So he's not clear about which models. However, he does say that when it cracks it causes the engine to overheat at high speed while running at normal temperatures around town, so there's a good way of checking if you had problems.
Cheers,
Nigel