How do you loosen the serpentine belt on a '93 Chevy Suburban to be able to change the alternator?
Usually if you have trouble finding the ten. pulley on these types of motors. You can tug on the belt real hard and look for a pulley that is moving. That's your ten. And very true about launching the wrench!!!
generaly these cars have a tensioner pulley... to loosen the belt, find the tensioner pulley, and loosen the bolt that keeps it from moving up and down.(could be on the block, but look around...) use a box end wrench on the bolt or nut head in the middle of the pulley... you will need to find the best starting position for the wrench as you will need to move the pulley and pull the belt off at the same time. the pulley will have spring tension on it so be careful not to launch your wrench when you let go! good luck
Some of the problem may be that the '93 is made by GMC not Chevy (weird). But, the tensioner pully is typically located at the top of the belt assembly. It is a smooth pully that has the word "load" and an arrow showing which way to turn the bolt. It will hacve a bolt in the center and can be loosened with a 15mm socket. Once it is loose, rotate the tensioner pully until the belt can be taken off or put on. Push the pully back in to the vertical position with the belt in place, then retighten your bolt