blower motor chatters

on my 1995 318i, the blower motor "chatters", sounds like a playing card is smacking against the squirrel-cage fan blades....I'd like to remove the fan motor and squirrel-cage, and check for any cracks, and it looks like it can be removed from under the engine hood. I think I can see it just behind the wiper motor. How can it be removed?
What is the sequence for removal? And, how easy is this to do?
Thanks