The first thing to do when learning how to replace a serpentine belt is to find the routing for the belt. Look on the radiator support shroud for a placard depicting the routing. Should the placard be absent, look in the owner's manual. If neither is available, turn to the internet.
Once the routing is acquired, look at its accessibility. See if your hands can reach the pulleys including the crankshaft pulley. Look at the motor mount if the vehicle is a front wheel drive and make sure it does not interfere with the removal of the belt.
If the engine sits so close to the frame that it is impossible to reach the pulleys from the top, the belt must be accessed through the wheel well. Also if the motor mount interferes, it needs to be removed only after supporting the engine with a floor jack.
Inspect the belt tensioner to see which the tool is necessary to move the tensioner. If it is a spring loaded tensioner, which is found on 90 percent of the domestic vehicles, it will have a square hole in a 3/8- or a ½-inch diameter for a ratchet. If it has a square nub, it is intended for an open end wrench.
Assuming that it is a tight-quarters situation, which is usually the case, the belt will be extracted through the fenderwell. This procedure is exactly the same if it can be accessed from the top, less for removing the tire and splash shield.
Raise and support the vehicle on jack stands. Remove the tire/wheel assembly and take out the inner splash shield.
Loosen the tension by using either the wrench or ratchet, whichever was deemed appropriate, and push the tensioner away from the belt. Pull the belt off of the tensioner pulley or another pulley if more practical, and relieve the tension on the tensioner. Remove the belt.
A good tip that should be kept in mind is that the spring-type tensioners will move out quite a bit when the belt is removed. To better illustrate, if the tool is straight up to start when the belt is installed, when the belt is removed and the pressure released from the tensioner, the tool will rotate about 90 degrees. It is difficult to keep the pressure on the tensioner due to the spring pressure so watch your fingers. The tool will pinch your fingers hard against anything in the path of the tool when the tensioner recoils. Place the tool in a position to prevent this.
When installing the serpentine belt, tension must be kept on both sides to keep the belt from falling back off. This always happens to the best of technicians unless the belt is secured at the top and enough tension kept on the belt to keep it in place.
Another good tip is that all the pulleys that are smooth with no grooves are made for the top smooth side of the belt contact.
Install the belt around the crankshaft pulley and while holding a little tension on the left side of the belt, work counter-clockwise installing the belt. If the tensioner is at the top, leave the slack at the tensioner and if it is not at the top, install the belt over the tensioner and leave the slack at the most convenient pulley to grasp. Install the tensioner tool and push the tensioner away from the belt. The slack in the belt allows the belt to be pushed onto the last pulley. Relieve the pressure on the tensioner allowing it to apply tension on the belt. Check all the pulleys closely to make sure that the belt is securely sitting in the pulley grooves.
Replacing a serpentine belt is not difficult, but you need to know what to look for so that you know when its time has come.
Installing a serpentine belt can be easy or difficult, depending on the make and model of your car. Learn the basics and avoid the pitfalls.