308 water pump impeller crack?

I wouldn't be too concerned with the crack, and doubt that the impeller would fly apart. However, I don't like that impeller at all -- webs too thick, webs sort of short, and the holes seem a bit odd to me (plus being a rough, cast steel/iron piece). With the impeller being pressed onto the shaft, I'm pretty sure that that's something aftermarket or something developed by an aftermarket Rebuilder.

Ferrari went thru some nuttiness with a plastic impeller, but here's the more "standard" design (I believe they went back to):

https://www.ferrariparts.co.uk/part/ferrari/103806

 

What year is your pump? My ‘82 308i has a brass impeller iirc.

 

It more likely a bad casting

 

I would not hesitate, just replace it with a new one . I would not trust that unit whatsoever.

G

 

I used the Flying Dutchman some 10plus years ago. They modify the bearing cage to a two piece bearing in the front, at least for the 308i belt set up it works great. Also uses a standard pump seal just like pool pump. Never had a problem.