As usual I'm getting confusing and conflicting information digging around the forums.
Opinions please -
SNG Barratt do oem and aftermarket pumps. Oem has plastic impellers, aftermarket has aluminium.
They say aluminium is better (as you'd expect) and try to get people to buy those - however I saw somewhere on a post that aluminium suffers with the coolant and plastic is better?!? Does anyone know? What do you do?

 

RESOLVED - I have made my mind up plastic for a whole host of reasons found on various sites. What I'm staggered by is the price I can get one from Berkshire Jaguar Components - oem too, a million miles cheaper than everywhere else! A very good find for anyone who needs to know

https://www.berkshirejagcomponents.c...12-c2x22603768

I did ring them to confirm it was oem

 

You should put your year, make and model in your signature.

The 4.2 engine has some good aftermarket pumps. Not sure about the 5.0. Just want to make sure you get one with a nice flat machined matting surface, and a good gasket.

As for the AL Vs Plastic argument, the entire block is aluminum so I don't see how an aluminum impeller wouldn't last in there.

 

I've done my signature this afternoon, hopefully it works now., Its a 4.2 XKR.
I've been doing a lot of general research on the topic, and the engineers consensus appears to be that if the bearings go and you have aluminium impellers you can potentially kiss parts of your engine goodbye. Plastic ones it seems are designed to break in the event of a bearing failure, but don't go brittle and break blades in the average 50k life of a water pump.
Either way I'm planning to change mine as the car is at 57k, and just in case I get a bearing fail before the next 50k (not that I'll be alive by then doing only 3k a year max) I shouldn't experience a mess if I go plastic. The aftermarket ones out there are plentiful, however as per SBS's engine build thread I've learned about the Berkshire guys who supply oem for a tiny fraction everyone else charges, and its because they told me they go to the supplier direct. They seem to have a very good reputation and have given me a tone of advice too.