There is no way that I could change the serpentine belt from the top of the engine for my Contour. There are too many things in the way. If you can do it for your 'Tour, then more power to you. Try it from the top first, it can't hurt.
Here is how I did it:
- remove the splash shield from the front right fender
- jack up the front right of the car and put it on a jackstand
- remove the front right tire
- insert a breaker bar or similar tool (I used a Sears 3/8"-drive flex handlepart part # VVQ 44363) into the tensioner pulley from the bottom of the car
- rotate the flex handle clockwise to loosen the tension on the belt (this is opposite the way you would normally loosen a regular bolt)(FYI: I actually tried to loosen the tensioner counter-clockwise for about five minutes once and wondered why it wasn't budging!)
- while the tensioner is loose, pull off the old belt (you might need an assistant for this part)
- release the tension that you were applying to the flex handle
- at this point you might want to compare the two belts and make sure that they are about the same length (the old one might have stretched a little)
- you might also want to check each of the pulleys and make sure that they are on tight and that the idler pulley and tensioner pulley spin properly (they have been known to have broken bearings)
- install the new belt on all of the pulleys but one (I choose the A/C pulley since it is easy to access from the wheel well)(FYI: if you forget how to route the belt on all of the pulleys, there is a diagram under the hood on the wheel mount)
- once again rotate the flex handle clockwise to loosen the tension on the belt
- install the new belt on the last pulley (you might need an assistant for this part also)
- remove the flex handle (this is VERY important!)
- check that the belt is properly installed and seated on all pulleys
- start the engine and make sure that the belt is seated properly
- install the tire
- lower the car
- install the splash shield
I did this from memory, so hopefully I got it all.
The hardest part is getting the breaker bar into the slot. I had to buy three different tools before I could get one that would fit with the limited space available.
Oh, and by the way, the water pump belt is a piece of cake to replace. Once you take the front plastic cover off (three bolts), you can release the tension of the belt with your hand.