Drive belts last a long time these days—usually upwards of 100,000 miles. But eventually, they crack, fray, and require replacement.
Is your drive belt looking like it has seen better days? If so, you might want to try replacing it yourself. Usually, swapping out a belt is a relatively straightforward job that requires only basic hand tools.
Drive Belt Replacement: How-To
Most modern cars have a single serpentine belt that wraps around all engine-driven accessories (i.e., the alternator, A/C compressor, etc.). The belt connects the accessories to the crankshaft pulley so that they can be driven off the engine.
On the other hand, older vehicles often use multiple v-belts (also known as fan belts) to connect the accessories to the crankshaft pulley.
Tools Needed to Replace a Serpentine/Drive Belt
Because most vehicles on the road today have a serpentine belt, we’re going to cover replacing that type of belt in this article.
The tools needed to perform serpentine/drive belt replacement will vary, depending on what type of car you have.
In general, however, you’ll need:
- Repair manual or access to a repair database
- Safety glasses
- Serpentine belt tool, breaker bar, or long-handle wrench (depending on the vehicle)
Serpentine/Drive Belt Replacement Instructions
Before we begin, keep in mind—all vehicles are different. The information below is generic and for entertainment and educational purposes only. Be sure to follow the repair information for your specific application.
Repair manuals, such as those from Chilton, are useful, but a subscription to a repair database is even better. ALLDATA and Mitchell 1 both have single-vehicle subscriptions for DIYers that provide detailed factory repair information.
You can learn more about accessing quality repair information in this article.
Serpentine/Drive Belt Removal:
- Put on your safety glasses.
- Note how the belt is routed before removal. Some vehicles have a belt routing diagram decal located in the engine compartment for reference. You can also use your phone to take a photo of the way the belt is routed.
- Locate the drive belt automatic tensioner. Depending on the tensioner’s design, it may have either a square slot (that accepts the drive end of a ratchet) or a traditional bolt head.
- Using the appropriate tool, push the tensioner to rotate it away from the belt and relieve tension. The tensioner may need to rotate either clockwise or counterclockwise, depending on the design.
- While holding the tensioner back with one hand, use your other hand to slip the belt off of one of the accessory pulleys (choose the pulley that’s easiest to reach).
- Feed the belt out and away from the remaining pulleys, then remove the belt from the vehicle.
Serpentine Belt Installation:
- Compare the new belt to the old belt to ensure that they share the same design.
- Consult the belt routing diagram (or the photo you took earlier). Then route the belt over all but one of the pulleys (leave the easiest to reach pulley for last).
- Hold the belt close to the last pulley with one hand, then use the other hand to rotate the tensioner with the appropriate tool.
- Use your hand to slip the belt onto the final accessory pulley.
- Once the belt is in place, you can release the tensioner slowly.
- Double-check the belt one more time to ensure it’s routed correctly.
- Start the engine to check your work.
Helpful Drive Belt Replacement Videos
To give you a better idea of how to perform the steps outlined above, we’ve included some helpful videos that demonstrate drive belt replacement: