I used this yesterday to replace the water pump on my son's 1998 Blazer, and first of all I want to thank Blaze for writing this, and the person who supplied the photos. Great job guys!
I'd like to add a couple of comments in the interest of helping others:
1) I wasted a lot of time trying to loosen the large nut holding the fan. I actually rented a took kit at AutoZone (Advance didn't have it); but it didn't work -- wrong sizes I guess, I never figured out how it worked. Anyway, the way I got it loose was to put additional tension on the belt, and repeatedly whacking the adjustable wrench until it came loose. To get the extra tension on the belt I put a 3/8" socket wrench head (the square part) into a square hole in the belt tensioner (left side of engine when viewed from front, below alternator), and had my son pull up on the socket wrench while I whacked the side of the adjustable wrench repeatedly. It didn't come loose easy -- took about 10 really hard whacks.
2) If you're going to use an adjustable wrench to loosen the big fan nut, you have to have a big one. I had to use my biggest one.
3) Don't make the mistake I did and try to put tension on the belt by putting a socket on the nut holding the belt tensioner. You don't use a socket at all. You insert the square head of the socket wrench into the pre-cut square hole in the tensioner.
4) I didn't use the radiator drain plug to drain the radiator. It had a special head I couldn't turn by hand, and I was affraid I'd ruin it if I turned it with a flat-head screw driver. I just drained the fluid by removing the water pump.
5) There is a large hose that connects to the water pump that is not shown in these pictures. It's on the bottom left. No big deal to remove it too.
6) Aligning the new pump in order to insert the 4 bolts is awkward. To facilitate alignment, I put a couple of smaller screws in the two top holes of the pump, and inserted them into the engine holes to temporarily hold the pump in place while I screwed in the two bottom bolts.
7) We went ahead and replaced both the thermostat and the serpentine belt too. The thermostat is held in place by two nuts at the front center of the engine. I bought a gasket for it separately, but didn't need it, since the thermostat's rubber outer ring is in fact the gasket.
8) Advance sells a small pouch of blue RTV for 98 cents which is ideal for this. I used it on both sides of the two gaskets for the water pump. I didn't use any RTV for the thermostat, and it didn't leak.
Hope this helps you.