Many American made vehicles with V6 engines or larger have the serpentine or accessory belts on the front. These engines are considered “longitudinally mounted,” with the engine mounted lengthwise on the chassis. Many four cylinder vehicles have transverse mounted engines, meaning the engine is mounted at a ninety degree angle from the chassis, placing the belts on the side of the engine bay instead of the front.
If the belt appears dried out and cracks have formed, it will need to be replaced. Use a flashlight to get a good look at the belt in areas that aren’t as visible to look for signs of cracking elsewhere on the belt.
You may want to start the engine to watch the belt moving to look for signs of damage along the entire belt. If something has been rubbing on the belt, you will need to identify it and move it before installing your new belt.
If the plastic gauge seats into the belt far enough for the handle to make contact with the belt, it is too worn and will need to be replaced. You can do this test with the belt on or off of the vehicle.
There are applications for both iPhone and Android smartphones that can measure the depth of the tread on your belts. It’s important to remember that the application is not an expert opinion and may not always provide accurate information.
Always wear eye protection when working on your vehicle. Gloves can protect your hands, but are optional for this project.
Tuck the cable to the side of the battery to prevent it from coming in contact with the negative terminal. This will ensure the engine cannot be started while you’re working on it, protecting you and the engine from damage.
It may take a good amount of pressure to rotate the tensioner pulley down. Be careful to release it slowly with steady pressure to avoid injuring yourself or damaging the vehicle. As soon as you let the tensioner go, it will return to its usual position and put pressure on the belt again, so you will need to hold it in place as you remove the belt. Not all vehicles are equipped with an auto-tensioner. [8] X Expert Source Ed BeeryAutomotive Specialist Expert Interview. 19 November 2021. Consult your specific vehicle’s service manual to see if yours is.
If your vehicle has an alternator belt instead of a serpentine belt, this is the method you will need to use. Be careful not to damage the wiring going into the alternator. The alternator provides the power the engine needs to run through those wires.
If you do not have a diagram on the vehicle or in your service manual laying out the direction your serpentine belt travels through the pulleys, take a picture of it with your phone to refer to when installing the new belt. [9] X Expert Source Ed BeeryAutomotive Specialist Expert Interview. 19 November 2021. A strictly alternator belt will likely only go around an alternator pulley and the crank pulley at the bottom of the engine.
If your old belt was loose because it had stretched over time, take that into consideration when comparing the two belts. Make sure both belts have the same number of “ribs” or threads spanning the width of the belt.
You will need to keep tension on the belt with your hands as you slide it into place to ensure it doesn’t fall off while you’re looping it around pulleys. If your vehicle has a belt only for the alternator, you will need to only slide it around the crank pulley at the bottom of the engine.
Do not simply release the auto-tensioner, as that could damage the belt and cause injury. Instead, reduce the pressure you place on it slowly. [14] X Expert Source Ed BeeryAutomotive Specialist Expert Interview. 19 November 2021. Remove the wrench or breaker bar from the tensioner pulley once this is done.
Try not to remove the bolts to the alternator completely, as they will be difficult to reinstall under the pressure of the belt. [16] X Expert Source Ed BeeryAutomotive Specialist Expert Interview. 19 November 2021. Make sure the belt seats on the alternator pulley completely.
Don’t tighten one bolt completely before moving to the next one. Instead tighten one halfway, then the other, before coming back to the first. If the belt seems to be putting too much pressure on the alternator, check again to make sure you have it run through all the other pulleys properly.
You can purchase belt tension testers at many auto parts stores that will tell you for certain that the tension in your belt is sufficient. If the belt feels loose, check to make sure it has been run through all of the necessary pulleys properly.
Make sure the ground cable is tight and won’t come off while driving. A loose or disconnected ground cable could cause the engine to die.
