Remove main lower engine cover, then remove the front lower cover. The pump is right there. Unplugging it is easy. But the inlet and outlet hose are held on by the typical constant pressure clamp. I have the cable operated tool to loosen them but access was extremely tight. In order to facilitate access to the hose clamps I removed the bracket/clamp bolt so I could manipulate the pump a bit. Still, it was tricky to loosen the clamps. The other problem was the nipples on the pump are close to 2" long for some unknown reason. It was difficult to slide the clamp that far off given the cramped quarters and the fact that the hoses have an elbow not far after the inlet/outlet. Once I got through that, the remaining difficult part was just sliding the hoses off the nipples. This pump appeared to be original so the hoses were pretty stuck on the nipples and it just took a lot of pulling and twisting. I was also afraid I was going to stress the hoses or a T that I saw in the loop.
New pump. 2023 production. It was a reman (from the dealer).
The base E63 gets the same Bosch 010 pump that was the revised pump the E55 got (which mine actually had when I bought it). But the S model gets this higher flow Pierburg.
Installation was mostly much easier. I was dreading hose installation since removal was so hard and I just couldn't get my hand up there to push the hoses on very effectively. The trick I decided on was to lightly lube up the inlet and outlet nipples with silicone dielectric grease. This worked really well. The hoses slid on fairly effortlessly. Getting the hose clamps in position was a bit tricky but not too bad. The remaining part I struggled with was the retaining bolt for the bracket/clamp. I found that if the bolt was a bit longer this would have probably made the job a lot easier. As it was, you had to sort of compress the rubber on the bracket/clamp while simultaneously starting the bolt and the bolt access was not great. Eventually I got it.
The moral is, I don't want to be replacing this pump regularly. I did modify the relay for the pump to be always on but I figure I should get years of service out of it anyway. The original pump still worked and it's not fully conclusive how much better this one works. My test after seemed good at least.
Oh, for filling I decided to vacuum fill. Given that the small reservoir (these get an isolated loop for the intercooler unlike, uh, pre-facelift E63s or possibly just the non-S models?) is the highest point I think I could have just filled it up. But I did the vacuum fill. Then I ran out of coolant. Had to run to O'Riellys for more G48. I should actually check the level.