Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
In order to remove the fan clutch you need a fan cluch tool. The clutch itself is threaded onto the waterpump and needs a large/ thin wrench with a special holder to hold the pulley while attempting to remove the clutch. Below is a link to Matco Tools for an idea of what the tool(s) look like, I wouldn't purchase it from here, there are much more less costly versions at your local parts store.
Honestly, I have done it with a pry bar before, but the chances you'll dammage the pulley are too great. Another tirck you may want to try, is keep the belt on so that the pulley doesn't move and put the correct size wrench on it, hit the top of the wrench with a hammer in the direction your trying to remove it (counterclockwise). The "impact" from the wrench will often loosen the fan clutch, you would install it with the same method. Good luck, once you get past this-it's not so bad.