Ok..first step is to go buy a set of ETorx sockets. They are the reverse of a Torx head and are used to remove the studs on the side of the engine. Decide at the same time if you want to change your belt. This is the perfect time, there is no better time.
Armed with your etorx, (all sockets are deep) 10mm, 13mm, 15mm, 17mm and 19mm (or lug wrench). Jack and small board (fits under oil pan), 15mm wrench open end.
Loosen the 4 8mm bolts on the water pump pulley (unless you know the screwdriver through two bolts trick)
Untension your accessory belt (15mm) let it lay in the bay.
Remove nut from passenger side motor mount bolt. (long one right in front of water pump)
Jack and support the passenger side of the car (high enough to remove tire only)
Remove passenger tire and both splash shields
Rotate the power steering pump until one of the holes in the pulley is at 12 oclock. Using a deep 13mm through the hole, loosen the top bolt, the bottom bolt is through a hole at 6 oclock. Be careful when lowering the power steering pump. The oil pressure sender is behind it and can be broken relatively easy if the pump is dropped on it.
Jack and support motor gently with board to keep from damaging oil pan.
Lay down parallel to car with your head at the front of the car, look up inside engine bay at motor mount you took the nut off. It is held to the body under here by 2 15mm bolts. You do not remove these bolts, only loosen then 2-3 turns each. Do not try to remove them, they will hit the mount.
Look straight in the wheel well at the mount, the bottom bolt of the mount (2 oclockish on the HB) is a 17mm nut, remove that and hope the stud comes with it. If the stud did not come, use your new tools to remove it.
Stand up and remove the two nuts from the other two mount locations on the motor (15mm) Once these are removed, lower the engine 1 inch.
Looking straight down at the body side of the mount, remove the two 15mm bolts on the top of the body side mount.
Wiggle body side of the mount out of the engine bay
Use your new etorx to remove the studs from the engine side of the mount. Note where the spacers are located as you remove them and the mount. (FYI: The passenger side one that used to be behind the ps pump loves to drop it'* spacer into the abyss and is very tough to find later.)
Ok, your water pump is accessible...
Remove the 4 8mm pulley bolts, 4 13mm bolts and 5 10mm bolts.
Tap pump to remove.
Clean surface for new gasket.
Install new pump ensuring to put a little RTV or pipe sealant (like the LIM bolts) on each of the 13mm waterpump bolts.
Torque to uh..spec.
Put it all back together.
Yep..from memory..I think I've done it too many times.
00 Regal GS: All kinds of cool stuff.