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
buying a ratty example (of a BMW) is a parasitic relationship.(and you ain't the mosquito)
Ken Kanne, Silverhill, AL, E36 Forum Mod/Craigslist addict/Hoarder of all sorts of stuff
1995 318is "Bebe"; 1993 325is "Elvira"; 1985 635CSi "Katja"; 1984 633CSi "Sylvia"; 1987 325is "Odette"