Your engine isn't just made of pistons and valves. It is home to several important systems as well. These systems - cooling, electrical and power steering - are run by none other than the accessory belt. If this belt slacks at any point, any of those systems may stop functioning. That's why your car is equipped with an acc. belt tension pulley. This pulley prevents the accessory belt from slacking, ensuring that different systems in your car keep working. Without a reliable tension pulley, the engine may overheat, its battery may lose charge, or your car's steering may become heavier. So you have to make sure the accessory belt is kept taut at all times. If adjusting the acc. belt tension pulley doesn't help, it may be broken already. Finding one is easy here at Carparts.
• Smooth pulley surface prolongs belt life
• Features maximum wear resistance
• Runs cooler and lasts longer
Accessory Belt Tension Pulley Buyer’s Guide
- An accessory belt tension pulley keeps the drive belt properly aligned and running smoothly by providing it with a rotating point to loop around.
- Without a reliable tensioner pulley, your car’s drive belt system will not work properly, putting all the belt-driven components at risk of malfunctioning or completely failing.
- Symptoms of a bad accessory belt tension pulley include loud squealing or grinding noise, visible signs of wear, premature belt wear, belt travel, and inability to rotate.
- As a general rule of thumb, the tensioner pulley should be changed every 50,000 to 100,000 miles.
- The price of a direct-fit accessory belt tension pulley replacement generally ranges between $5 and $250. You can buy this part individually, by sets of two, or as part of a kit.
- Compatibility is important when choosing a tensioner pulley replacement to ensure that it will function efficiently. Our website makes it easier for you to find a unit that fits your vehicle — simply enter its year, make, and model to get specific results.
Your car’s engine bay is home to more than just the power-generating engine block. It also houses the engine accessories that keep your car running smoothly, including the water pump, alternator, power steering pump, and air conditioning compressor, among others. In order for these accessories to work, they need to draw energy from the engine. This is why your car is equipped with an accessory drive belt system that’s made up of several important components, one of which is the accessory belt tension pulley.
What is an accessory belt tension pulley?
The accessory belt tension pulley is one of the principal parts of the belt tensioner, along with the tensioner arm, spring and base. The pulley keeps the drive belt properly aligned and running smoothly by providing it with a rotating point to loop around. It plays a role in maintaining the correct tension of the accessory belt so that it efficiently runs from the crankshaft and transmits power from the engine to the belt-driven accessories.
The drive belt system where the pulley can be found is typically located in front of the engine, where the belt moves in tandem with the engine’s revolutions. Tensioner pulleys that ride on the outer portion of the belt have a smooth outer wall, whereas tensioner pulleys riding on the inner portion of the belt have a grooved surface designed to slot into the grooves of the drive belt to keep it from slipping away.
Be careful not to confuse tensioner pulleys with idler pulleys. Even though they look and function the same, they’re still different in that the idler pulley is mounted to a fixed structure while the tensioner pulley is attached to an adjustable device.
How long does an accessory belt tension pulley last?
There are many factors that can affect the lifespan of your car’s tensioner pulley, including its quality, the amount of wear and tear that it’s subjected to, and the integrity of the other components in the drive belt system. As a general rule of thumb, this part should be changed every 50,000 to 100,000 miles. You may also refer to your vehicle owner’s manual to see if there’s a recommended schedule for replacing the tensioner pulley.
Symptoms of a bad accessory belt tension pulley
Without a reliable tensioner pulley, your car’s drive belt system will not work properly, putting all the belt-driven components at risk of malfunctioning or completely failing. This is why it’s important to make sure that the pulley is in good condition at all times. Knowing the signs of a damaged pulley that’s in need of a replacement can help you address the problem before it escalates and compromises your vehicle’s overall performance.
Loud squealing or grinding noise
A squealing noise from the drive belt is often the first indicator of a damaged tensioner pulley. There are many potential causes behind this issue. If you hear the squealing every time you start the engine, then it’s likely that your car’s tensioner pulley has gone loose, causing the belt to create a screeching sound as it rubs against the surface.
If the sound you hear is similar to grinding, then the metal parts of the tensioner pulley, particularly the bearings, may be to blame. When these metal parts wear out, they grind against each other and create an alarming grinding, clattering, or rumbling noise.
Visible signs of wear
Visible signs of wear such as scoring, scuff marks, and cracks on the surface of the pulley are common telltale signs that it needs to be replaced. This is caused by miles of repetitive rubbing against the belt’s surface. Since the drive belt assembly is not one of the parts commonly examined during regular maintenance checks, it can be easy to overlook this symptom.
Damaged bearings can hamper the movement of the pulley and cause it to seize up. When the drive belt moves over the surface of a stuck tensioner pulley, it may produce a squealing sound, rip up, or fall off the engine. A frozen pulley will no longer rotate freely when you try to spin it by hand.
Premature belt wear
A damaged pulley may cause the drive belt to become worn out long before the end of its service life, resulting in fraying and wear patterns throughout its length.
When your car’s tensioner pulley becomes significantly deteriorated, it will no longer be able to route the drive belt and maintain correct tension. This results in a slackened belt that visibly wobbles from side to side when you look at it while the engine is running on idle.
Accessory belt tension pulley replacement
There are many ways that a tensioner pulley can be damaged. As it constantly spins against the belt, it will become worn out and loose over time. Plus, corrosion and dirt may damage its bearings and make it move less freely. Incorrect belt tension can also keep the pulley from operating under the pressure it’s designed for.
Even worse, a damaged pulley may put your vehicle’s engine at risk of overheating and failure. The good news is that it doesn’t take too much time to replace this part. A professional mechanic may be able to replace it in less than an hour.
How much does an accessory belt tension pulley replacement cost?
The price of a replacement accessory belt tension pulley depends on your vehicle’s year, make, and model. The price of a direct-fit replacement generally ranges between $5 and $250. You can buy this part individually or in sets of two. They’re also sold as part of a kit.
Finding the right fit
As with any automotive part, compatibility is important when choosing a tensioner pulley replacement to ensure that it will function efficiently. To guarantee that you get the right fit, refer to your owner’s manual or your car manufacturer’s website for the specifications of its accessory belt tension pulley. Our website also makes it easier for you to find a unit that’s compatible with your vehicle — simply enter its year, make, and model to get specific results.
Replacing an Accessory Belt Tension Pulley in Four Easy Steps
Many people think that working on a car's belt system is a complicated and daunting task. However, the challenge only revolves around knowing which pulley drives a certain device. Being able to identify the role of each part is already half the battle. With the accessory belt tension pulley, locating and replacing this is even simpler because there aren't any major devices connected to it. This guide shows how doable this job is. Using simple tools and following four easy steps, one can change the tension pulley in no time.
Required skill level: Novice
Needed tools and materials
Socket and wrench set
Replacement accessory belt tension pulley
Replacement serpentine belt (if necessary)
Preparing the vehicle
Kill the engine and engage the parking brake. Pop the hood and give the motor enough time to cool to prevent accidental burns. After a few minutes, disconnect the batteries and remove any other accessories that get in the way of the engine. Read the car manual to get an idea of the layout of the car's belt assembly.
Disassembling the belt drive
Locate the belt tensioner. Drive the proper bolt head on it to give the belt assembly some slack. Use a lead pipe as an extension to have more leverage. Once everything is loosened, pull the serpentine belt off and keep it in a safe place. Replace this belt later if necessary. Next, locate the tension pulley and remove it. Don't misplace any bolts and other small hardware. These will still be used for reinstallation.
Installing the pulley and belt
Grab the new belt tension pulley and slot it in the same location of the old one. Tighten it on the assembly before moving on. After the pulley, install the new or reused serpentine belt. Refer to the car's manual for the proper layout. Take note of the right routing and direction. Work on the belt tensioner to tighten the assembly.
Return any devices removed prior to accessing the belt assembly. Reconnect the batteries. Start the car and test if all belt-driven devices are working properly.
AC Delco vs. Dayco: Which is the Better Accessory Belt Tension Pulley?
It's very difficult to differentiate two aftermarket parts that claim to be genuine OE replacements. This was the trouble we faced when we were tasked to compare the accessory belt tension pulley from AC Delco and Dayco. They are recognized suppliers of high-quality components that rarely let anybody down. We didn't expect anything different when we tried their pulleys on our '93 Saturn SC1. Here are the things we discovered:
Dayco and AC Delco pulleys have very similar costs. A price tag of around $23 was put on the former while $24 was given for the later. This small difference didn't really weigh much at all for us as buyers.
WINNER: Dayco and AC Delco
The test of any part that claims to be an OE replacement rests on how well it fits and conforms to the rest of the car's parts. The pulleys from Dayco and AC Delco perfectly slotted in place to the belt assembly of our SC1. Installing these wasn't really rocket science. Both easily found their working area and accommodated the serpentine belt without any trouble.
WINNER: Dayco and AC Delco
As far as performance was concerned, both pulleys from each brand had its own high points. We weren't able to find any substantial differences between the two. Dayco was spinning smoothly, was really quiet, and was light and easy on the belt. AC Delco's pulley was very reliable even under extreme conditions, had no squealing whatsoever, and was very dirt resistant.
WINNER: Dayco and AC Delco
AC Delco's steel pulley was very durable and performed very well for a long time. We were surprised by this fact considering the part really felt like tough plastic. Dayco's was made of various polymers and was able to take its own share of stress as well. Based on our experience, both really did survive the rigorous tests we put on our SC1.
WINNER: Dayco and AC Delco
Was it really possible to separate the accessory belt tension pulley from Dayco and AC Delco? Sadly, our little experiment didn't result to anything significant. Both brands really performed well as an OE replacement for our Saturn. At the end of the day, we think that it really doesn't matter which one you choose.
Dos and Don'ts in Choosing an Accessory Belt Tension Pulley
Your car's accessory belt needs the proper amount of tension in order to function effectively. The tension applied on the belt comes from the accessory belt tension pulley. When looking for a high-quality belt tensioner pulley, you need to look into the do's and don'ts to avoid getting the wrong one.
- Refer to your vehicle's manual for your car's belt tensioner pulley specifications. If you don't have the manual with you anymore, there's always the internet to search on. Just make sure that you get the data from a trusted online source, such as your car manufacturer's website.
- Check which flange is suitable for your vehicle. Getting the right match ensures compatibility. To identify the flange suited to your pulley, you need to know your pulley's width, and its inner and outer diameters. Two types of flanges for the belt tensioner pulley are steel and polymer.
- Look for a belt tensioner pulley with lubricated ball bearings and double high temperature. These features offer peak bearing performance.
- Go for a belt tensioner pulley that's covered with a long-term warranty. The usual warranty period is 1-year with unlimited-mileage.
- Don't buy a driver's side belt tensioner pulley if you're looking for a passenger's side tensioner pulley replacement. This can lead to accessory belt malfunction, which in turn, can cause engine damage.
- Don't purchase a used belt tensioner pulley unless you've assessed its remanufacturing origins. Be suspicious of overly cheap used tensioner pulleys as these are most likely damaged. Check your supplier and the actual belt tensioner pulley before buying it.
- Avoid getting low-quality belt tensioner pulleys in exchange for a cheaper price. When you examine the situation carefully, these low-quality pulleys break faster and require replacement more often than standard ones. Therefore, the sum of adding up the costs of numerous low-quality pulleys is equal or even greater than the price of one high-quality pulley.
How to Change Your Vehicle's Accessory Belt Tension Pulley
The accessory belt tension pulley enables the belt tensioner to move up and down. It applies the proper amount of tension to the belt during engine operations. Over time, the tensioner pulley may get worn and eventually freeze up. This can lead to belt damage due to the friction caused by the belt sliding across the stuck pulley. In order to prevent this, replacing your broken tensioner pulley immediately is recommended.
Difficulty level: Moderate
Tools to be used:
- Flathead screwdriver
- 3/8-inch drive breaker bar
- Bungee cord
- 8 mm hex-head socket
- Socket set
- Torque wrench
Step 1: Shut down the engine and engage the parking brake. Open the hood and let the engine cool down for a while before starting the repair.
Step 2: Observe the top of the fan shroud and look for the accessory belt routing diagram. It's usually stamped to the fan shroud. Otherwise, you may find it stamped to the underside of the hood.
Step 3: While standing in front of your engine, find the accessory belt tensioner and pulley located on the engine's front-center. You'll notice a black plastic cover at the center of the pulley. Pry this plastic cover off the tensioner pulley's center using a flat-head screwdriver. Keep the cover in a safe place. Once the plastic cover is removed, you'll gain access to the hex-head hole inside the tensioner pulley.
Step 4: Get the 8mm hex head socket and slide it onto the end of a 3/8-inch drive breaker. Insert the hex-head socket into the hex-head hole inside the tensioner pulley. Use one hand to turn the breaker bar clockwise in order to release the tension from the belt.
Step 5: Using your other hand, slide off the tensioner pulley. With utmost caution, release the tensioner and remove the breaker bar. Get a bungee cord and hang the belt from one of the top engine accessories, keeping the belt in place while the pulley gets replaced.
Step 6: Locate the bolts mounting the tensioner to the engine's front. Use a ratchet and socket to unbolt the tensioner. Put the bolts in a safe place.
Step 7: Pull the tensioner off the engine's front. Then, get the new tensioner pulley and pry its plastic cap off. Install the new pulley on the exact area where the old one used to be. Secure the tensioner in place by screwing the mounting bolts and making sure that they are tight enough. Use a ratchet and socket to complete tightening the bolts.
Step 8: With a torque wrench and a socket, torque the tensioner mounting bolts between 25 and 30-foot pounds. Position the hex-head socket and the breaker bar onto the new pulley. Reinstall the belt by turning the breaker bar clockwise with one hand, and removing the bungee cord with the other hand. Release the tensioner cautiously and remove the breaker bar.
Step 9: After the new tensioner has retracted, bringing the belt to proper tension, snap the plastic cover back into the pulley. Refer to the belt routing diagram to re-route the belt around the pulleys.