Ok, enough with the plastic water pump impelers

[bmw540san]

I just read another thread of plastic impellers fear.

How about we state the facts and no I'm not trying to argue but just to stop with internet rumors.

Yes, long time ago, BMW did the blunder with poor quality composite impellers and there was number of failures where impellers disintegrated.
BMW fixed this with updated style composite impellers and I'd like to hear of recent documented failure.
I replaced number of WP's with quite a bit of age on them with worn bearings (weeping holes) and yet to find composite impeller issues.

On the other hand, I constantly hear of talk that metal impellers are better while opposite is true: Cast metal impellers are harder to balance and are heavier which is more stress on bearing.
Also, spot welded metal impellers are often poor quality and spot welds can fail and cause impeller to break free.

When it comes to WP, I actually choose OEM WP with composite impellers or OEM equivalent such as Saleri.

No, I'm not the greatest mechanic out there and actually far from it, but sometimes all of us including me unknowingly spread false rumors.