Any recommedations on MCS water pumps : Hepu (aluminum impeller/German), Graf (resin impellar/Italy), Saleri (OEM supplier) or Gates ( unknown/ USA ) and what's the advantage of buying the pump complete ?

 

I haven't done this yet so take this for what it's worth...I was researching a replacement a while back and ran across this... an electric water pump...May be worth looking into...
http://www.hrpworld.com/store/defaul...-pump-kit.html

 

From experience in our shop we ONLY install factory MINI original pumps. We've tried the aftermarket like gates and such and they are NOT built to the same quality standards as the MINI box ones. Since we warranty all our work we had to replace the non original pumps for free costing us too much time and money. So for the price difference it isn't worth doing it twice.

Here is the original MINI ones we use and have a 2yr warranty
https://www.waymotorworks.com/r53-water-pump.html

 

+1 on the OEM pump, replaced it last year while repairing other cooling items.

You might want to also check/replace the o-ring/flange connecting the pump to the block too. Mine looked like following and was leaking. It's also possible to replace the pump without removing the SC.

 

I did not remove my SC when I did my pump replacement. What makes it also easier is to remove the driver side horn from the SC along with the BPV (upper right of picture). Also need to make sure that you remove the two bolts holding the o-ring flange portion from the engine block.

There is a recent thread where the guy broke a tab off the SC end that drives the pump. Thinking he did not remove those two bolts. You can get to them with the pump in place.

 

Does anyone know if the OEM waterpump impeller is composite or metal ?

 

Good question. I can't answer it, but I did just pull (to reuse) one with 93k kms. I have no reason to suspect it was changed in its life (could be wrong). It has plastic impeller.

 

Anyone know the center to center distance between the bolt holes and the diameter of the center hole?

 

Just go over to O'Reilly or Advance and ask for a replacement waterpump and get the the bolt spacing you are looking for...

 

Sorry if this wasn't clear enough - does anyone actually know what the center to center dimensions are between the bolt holes and the diameter of the center hole on the block flange?

There are lots of electric water pump flange adapters out there with an extension for attaching a tube - I wonder if there is a part already in existence that would do the job.