Following are instructions for replacing the serpentine belt on a late model 2.4L Cavalier or Sunfire with air conditioning (AC). The instructions for replacing the serpentine belt that can be found in Chilton's manual, on the Autozone website, and on this website (from what I've read) are wrong. In fact, all of those instructions seem to be copied from Chilton's manual (which I own). Replacing the serpentine belt is a fairly easy job (especially for two people) if you don't read the Chilton manual and stick to the following instructions. Although the following instructions are specifically for a 1996 2.4L Cavalier with AC, you may find the following instructions generally helpful for other types of Cavaliers/Sunfires-- but keep in mind that each engine configuration has its own pulley and tensioner configuration, which may also be affected by whether or not the car has AC.
Background: I recently noticed that the serpentine belt on my wife's 1996 Cavalier (70k miles) was damaged. About 1/3 of the belt was missing so it was narrower than it used to be. I was informed by experts that I should replace the belt immediately since it would likely be a short time before the belt would completely break and the car would be essentially disabled (because the belt drives the water pump, power steering, alternator, and AC).
DISCLAIMER: The following instructions worked for me on my 1996 Cavailer LS 2.4L with AC. The following instructions may not work for you, even if you have the exact same type of car, and especially if you don't. Model year, engine size, and air conditioning affect the pulley configuration and the serpentine belt configuration. If you are not confident or competetent to do this kind of work, please hire a trained automotive maintenance professional. I take no responsibility if you hurt yourself or your car by using the following instructions.
Tools: 13mm box wrench. (Some model's engines require a 15mm box wrench.) Preferably a pipe or something that you can slip over the box wrench to extend the reach and leverage of the box wrench. Workman's gloves. (This is close-quarters work and your hands will likely get hurt if you don't wear gloves.)
1) Get a new belt. The belt size depends on the engine type/size and (I guess the year and whether or not your car has AC). Your local parts store should be able to help you. I just bought a Goodyear belt (part #: 4050475) at Kragen's for $22 for my 1996 Cavalier LS 2.4L (with AC). Prices ranged from $19-23 at my local parts stores in Silicon Valley in 5/08. Your size may be different. Double check the store's selection. If the belt is the wrong length you will waste a lot of time. It is interesting to note that in the above part number, the "475" stands for 47.5 inches.
2) Get some lighting. This is close-quarters work and it's really hard to see down into this part of the engine. Make sure that you have some good, adjustable lights (and perhaps a flashlight) that you can shine down there.
3) Take note of the belt configuration. Or take a picture or make a drawing of how the old belt wraps around the various pulleys. I've read some people post that the diagram for the serpentine belt is located on the hood, but it wasn't on either of my Cavaliers. There was however a crude (but useful) diagram on the packaging of the new Goodyear belt that I bought.
4) Get a helper. It's not too hard to get the old belt off without a helper. And it may be possible to get the new belt on without a helper. But I think you'll find that an extra set of hands will make putting the new belt on much, much easier and faster.
5) About the tensioner: There is a spring-loaded tensioner wheel that keeps the belt tensioned properly. On the 2.4L engine, that tensioner wheel is located just below (and maybe an inch back from) the alternator pulley. All of the other pulleys on my car have grooves for the belt. The tensioner wheel, however, is smooth (since it rolls against the smooth outside of the belt). There is a 13mm hex head "bolt" on the end of the tensioner pulley. There was not enough space between the bolt head and the wheel well for me to put a socket wrench on it. But I was able to put a 13mm box wrench on the bolt head. The Chilton's manual tells you to "turn" that bolt clockwise to loosen the tensioner. For my car, that was WRONG. First of all, I'm not even sure that bolt actually even spins. I definitely couldn't spin it clockwise. (Maybe counterclockwise a tad). But I don't think that would have helped anyway. From reading the Chilton's manual, I was under the impression that you loosen the tensioner by spinning the bolt clockwise. From what I can tell, it's NOT about SPINNING the bolt (clockwise or counterclockwise). From what I can tell, that bolt serves as a place to grab onto the spring-loaded tensioner wheel and gently pry it up and back (away from the belt) so that you can relieve some of the tension on the belt, thereby enabling you to put the belt on or off the rest of the pulleys. (I wasted a lot of time trying to spin that bolt to no avail.)
6) Removing the old belt: Put a 13mm box wrench on the tensioner bolt. You probably want to position the box wrench so that unattached end is just about horizontal-- or actually pointing toward the top of the radiator. Pull up and back (towards the top of the windshield). Start by pulling gently, and then pull harder if you still need to move the spring-loaded tensioner wheel. You should be able to feel the tensioner wheel flex back (towards the windshield and away from the belt). At a certain point, it won't flex back any further. Don't try to force it any further. I've read about people who have snapped the tensioner wheel by manhandling it. If you can't flex the tensioner wheel by pulling up on the box wrench, you may want to try putting a breaker bar (or pipe) over the end of the wrench in order to get more leverage, but be careful not to hurt yourself or the car. (I used a pipe, to get the new belt on but I did not need a pipe to get the old belt off.) While you are holding the tensioner away from the belt with the box wrench, roll and slide the belt away from the alternator pulley. Once the belt is off the pulley, you can release the tensioner wheel. You should now be able to finagle the belt off the car.
7) Double-check your belt length. After you've removed the old belt, check it against the new belt to make sure that your new belt is the same size. Your new belt may be a tiny bit shorter because your old belt has stretched. But it should be almost exactly the same.
8) Installing the new belt: This part might take a lot longer than removing the old belt. It really helps to have a helper for this part. It's an easy job for the helper, so just ask somebody. For the my 1996 Cavalier (2.4L with AC) the belt placement is pretty straight forward. The inside (grooved side) of the new belt goes around all the grooved pulleys. And the smooth outside of the belt goes against the tensioner.
A. Start by putting the belt around the big drive wheel down underneath, across from the tire. Then put the belt around the air conditioner pulley (I think that's what it is) which is also down below but further front, just behind the radiator. You'll probably need to lay on your back and reach in from underneath to wrap it around one or both of these pulleys (hopefully while a helper keeps some tension on the belt from above so that it doesn't fall off.) Make sure that the belt is properly set in the middle of the pulleys.
B. Carefully run the outside of the belt in front of the tensioner wheel, but be sure to keep enough pressure on belt that it doesn't fall off of any of the other pulleys.
C. Start to loop the inside of the belt around the alternator pulley from the top-front. You won't be able to get the belt onto the alternator pulley until you pry up the tensioner wheel. In fact, you'll barely be able to even get the belt onto the edge of the alternator pulley. Hold it tight there while you perform the rest of these steps.
D. Double-check to make sure that the belt is properly set in the middle of all of the lower pulleys and on the tensioner wheel. (That is, make sure you didn't knock the belt off the center of the pulleys as you tried to work it behind the tensioner and onto the alternato pulley.) You may need a flashlight to check.
E. Put the 13mm box wrench on the tensioner wheel bolt (like before) and pry up with the wrench (like before) to loosen the tensioner wheel. It may be a bit tricky to get the box wrench on the bolt because the belt may be in the way, but you can push the belt in and do it. With the tensioner wheel pryed up, slide the belt onto the alternator pulley. (It may help to spring the pulley counterclockwise.) For this step, I found it helpful to put a pipe over the wrench, partly to gain leverage, but more importantly in order to create some room to work. It's easiest if one person lifts the wrench (or the pipe) while the other person slips the belt onto the alternator pulley.
F. Once the belt is properly seated on the alternator pulley, double-check to make sure that the belt is properly seated on all of the other pulleys (and the tensioner), and slowly release the tensioner wheel.
G. Again double-check that the pulley is properly seated on all of the pulleys.
9) Check your work. Start the car and make sure that the belt is working properly.
