Not entirely true.
Stock m42/m44 water pumps do come with a PLASTIC impeller but it has not been known to fail on the same scale as the 6cyl models. All of the horror stories are regarding the faulty 6cylinder water pumps with platic impellers.
There is absolutely no history of 4cyl pumps failing prematurely. I have two tis, one had the water pump replaced at 100k(was still working at 100%) and the other at 130k still has the original plastic pump.
SL
Quote:
| Originally Posted by bimmerboi318 Well, the m42/m44's that had a waterpump with a composite impellar, would fail prematurely. The impellar would deteriorate and then break up and overheat the engine quickly. I've read of several cases,some as early as 60k miles or so. |