My Water Pump failed on Sunday (e70 3.0si 140K); it was a hot day (35 C+) and I was cruising in the highway when a Yellow alarm got off indicating that the temperature was high; then 10 seconds later a Red Alarm came and the car went into limp mode...there was no time to get to the next exit and at least I had a place to pull over. Had to wait until the engine cooled off and called a flat bed to get the car home.

I'm in the mist of replacing the water pump & thermostat (started last night....still in progress.....) and looked for several hours for a full procedure; this is the best one ! and wanted to contribute some additional details:

1. I disconnected the Battery before starting...not sure if is a requirement or a precaution but just in case....

2. My radiator had a Drain Plug (Blue) in the bottom driver side and one Red a bit above in the same side (I read in other forums that some X5 models had no drain?) I removed both and drained as much Coolant possible. The Drain Plug (Blue) was stuck and broke when removing so I had to drill it out and have ordered a new one....hope it works...

3. Removing the Electric Fan assembly required to remove the Top Driver Side Radiator Hose connection; I could not take it out without doing this (or at least could not figure out).

4. As I had a drill already set (see #1 above), I decided to drill a small hole in the old Thermostat housing (is being replaced anyway) and that allowed me to drain the coolant there to avoid more mess when removing the hoses. It took a while (it was a small hole) but I was done for the night anyway.

5. I'm seriously thinking on removing the radiator as suggested on this chat; the space is very tight and I do not want to remove the right wheel / wheel cover. (I have the car on solid ramps).

..... will see how far I get tonight.....