Well it certainly make the job easier! Do you HAVE to? No, but it's gonna be a heck of a struggle working behind the blades, and you risk damaging the blades, too.
You should be doing a complete cooling system overhaul if it hasn't been done in the last 75K miles.
Quotes to live by:
guessing gets expensive
nothing is more expensive than a cheap BMW
Ken Kanne, Silverhill, AL, Honorary Forum Grandpa/Craigslist addict/Hoarder of all sorts of stuff
1995 318is "Bebe"; 1993 325is "Elvira" 1985 635CSi "Katja" 1984 633CSi "Sylvia"
I NEED A NAP, DANG IT!