I did this a little while back on my 116i and from a quick search on RealOEM it looks like it might be the same process/parts for you:
https://www.realoem.com/bmw/enUS/sho...diagId=11_5011
I don't have a guide as such, I just used the diagram on the realoem link to help find the pump location and part number for a replacement. Here are a few steps off the top of my head (assuming you've drained your coolant):
- Disconnect air hoses and remove the airbox for easier access to the engine bay
- Locate the water pump drive wheel (bottom left of the engine, see photos)
- Remove the drive wheel from the pump by taking out the 3 screws (worth replacing this at the same time. I didn't and had to within 2 weeks)
- Remove the 5 screws holding the waterpump in
- Put the new waterpump in palce, add some threadlocker (I used medium strength) to the bolts and hand tighten (do not overtighten these bolts, they are quick to crossthread). Think I might've torqued to 10nm, but it's probably not needed
- Put your (preferably new) drive wheel on the front of the pump - this is a bit of a pain but with some shoving and moving it gets there. You can then use a driver/pencil to line up the holes of the drive wheel with the holes on the pump
- Put some threadlocker (again I used medium strength) on the drive wheel bolts and hand tighten. Again, they're a bit of a pain when it comes to crossthreading
Engine Bay:
Engine Bay with airbox removed and waterpump drivewheel located:
Waterpump drivewheel (you can see the cuts in the rubber on mine, which is why I had to replace it):
Hope it helps!