If you don't have the correct fan clutch tool, don't even try. The job isn't that bad (make sure you get the O-rings), but getting that fan clutch off is a bear. The tool is well worth the $100 price tag, IMO.
As your truck is beginning to age, flush the coolant (use the right BMW coolant), replace the hoses and carefully inspect the radiator, they are known for early failures. Check the expansion tank, almost everyone that's been in the shop has had a cracked tank.