you need the special two piece wrench to remove the fan assembly. here's a link
http://www.partsamerica.com/ProductDeta ... yCode=2093
I'm sure you could do the job without this wrench, but I would avoid it at all costs! I replaced the water pump on my wife's (then girlfriend) Blazer and removed the fan without the special wrench... ROYAL PITA! anyhow, removing the fan is the trickiest part. It's very straight forward otherwise. just remember which bolt goes where; that's important.