Restore your engine's operating efficiency with a good timing via a new belt idler pulley.
You hear some unusual screeching noise as soon as you start your engine. But if upon checking your engine, you don't see anything wrong, then don't panic because it's just probably your belt idler pulley. Bolted onto the engine block, this timing belt pulley may look almost exactly like the belt tensioner pulley-it looks like a bearing with a very thick wall.
Like the belt tensioner pulley, it's designed to remove that annoying belt vibration that's caused by excessive belt slack. The only difference between them is that the tensioner is mounted on an adjustable bolt, while the idler pulley isn't. Aside from increasing belt tension, the belt idler pulley also prevents the flat belt drive from slipping, which is surely the last thing that you want to happen to your vehicle. Though its outer wall is smooth, it has retainers on the edges or a groove along the middle to keep the belt in place.
The best kind of pulley is that constructed from special glass-filled polymers and has smoother surface and stiffer dimensions for lesser vibration of your ride's belt. Also, its seals should be of double high-temperature standards for better bearing performance. To preserve it, make sure that its ball bearings are lubricated well. And to avoid frequent replacement, you can get it from a reliable auto parts store like The Family Car.
Accessory Belt Idler Pulley Buyer's Guide
Belt pulleys control the engine drive belts and supply power to engine accessories like the air conditioner compressor.
An accessory belt idler pulley sits on a fixed mount while its tensioner counterpart uses an adjustable bracket.
The idler pulley acts as the rotating point for the engine belt, keeps it stiff, and prevents it from slipping.
A bad or failing idler pulley will show visible wear and tear on its surface, make squealing noises, show cracks in its bearing device, or have a loose or warped bracket mounting.
Car owners will want a replacement accessory belt idler pulley that matches the engine belt’s dimensions, can withstand the constant wear and tear, and keep the belt from slipping.
The engine may generate the power that runs a vehicle, but the belt system delivers that energy to the rest of the machine. Its drive belts transfer the engine crankshaft’s rotary energy to the air conditioning compressor, the power steering pump, the alternator, the water pump, and other engine accessories.
To efficiently deliver power, the drive belts must stick to a designated path that keeps them out of each other’s way. They must also avoid passing too close to other engine parts. The job of keeping belts on the right track falls on the belt pulleys.
What is a belt pulley?
A belt pulley controls the various engine drive belts connected to the crankshaft. In turn, the belts supply power to engine accessories like the air conditioner compressor, alternator, and steering pump.
The pulley makes sure that the drive belts stay on the most efficient route around the engine bay. It also gets rid of the engine vibration caused by excessive slack in the drive belt system, leading to a quieter and smoother ride.
The two types of accessory belt pulleys based on the way they mount the engine are the tensioner belt pulley and the idler belt pulley. The tensioner pulley uses an adjustable mount while the idler pulley relies on a fixed bracket for support. Otherwise, the two types resemble each other and work in the same way. Some vehicles only have one of each pulley type, while others have at least two idler pulleys.
An idler pulley sometimes uses a sheave, a grooved wheel that holds a drive belt, which in turn goes over a roller. When the crankshaft rotates, so does the wheel. The belt in its groove sends the mechanical power, speed, and torque to the engine accessory on the receiving end.
What does an accessory belt idler pulley do?
The accessory belt idler pulley acts as a rotating point for the engine belt. By letting the drive belt move and loop around without interruption, the pulley keeps the belt from getting slack and causing disruptive vibrations in the engine.
The stiffer the drive belt, the more efficiently it transfers engine energy. The engine accessories enjoy a more stable power supply and work better, contributing to the vehicle’s overall performance.
In addition, the idler pulley also reduces the chances of flat belt drive slippage. Most accessory belt idler pulleys have retainers on the edges of their outer wall and some devices also have a middle groove. The two features make sure that a flat belt stays in place despite the belt’s slippery surface.
Symptoms of a bad or failing idler pulley
The accessory belt idler pulley and its parts will degrade from constant use over time. A broken pulley cannot deliver enough power to the engine accessories to run them properly.
For example, an idler pulley uses friction-reducing machine parts called bearing devices to help the drive belts move correctly and smoothly. If a bearing device gets damaged, it can cause the belt to slip from the pulley.
When an accessory belt idler pulley reaches its physical limits, it causes several recognizable symptoms that warn the vehicle owner to replace the damaged or worn device.
Visible wear and tear on the idler pulley
While checking the engine, take the time to inspect the surface of the belt system’s idler pulley. Look for scuff marks, scoring, and any other sign of wear and tear left by the drive belt after repeated and extended physical contact with the pulley’s surface. It helps to remember what a brand-new idler pulley looks like for accurate comparison. Inspect the belt as well for any signs of damage.
Squealing drive belts
An engine belt may issue an ear-piercing squeal when it rubs across the damaged contact surface of a bad idler pulley. It may also make the harsh noise when the pulley slips and either binds or seizes its length.
The squealing usually takes place while starting the engine for the first time. It will also get worse over time.
Broken bearing devices
The bearing device or the idler pulley itself can crack or fall apart. A broken pulley can disrupt the normal rotation of the drive belt, which either falls off the engine or gets torn up.
Since the drive belt provides engine accessories with the power they need to run properly, losing it causes engine malfunctions like stalling or overheating. While returning an escaped belt or replacing a damaged one will let the vehicle run again, the only long-term solution is replacing the broken idler pulley with a new unit.
Damaged bracket mounting
If both the idler pulley and the drive belt seem fine, the problem may lie within the fixed bracket that supports the pulley. Since the bracket sits on the engine, the latter’s vibrations will slowly loosen the bolt or deform the mounting. A pulley with an unstable foundation will wobble and fail to keep the belt on track.
Selecting a replacement accessory idler pulley
Most vehicles will go through several belt accessory idler pulleys during their service life. Car owners shopping for a replacement part should pick a model based on its size, durability, and ability to keep the drive belt from slipping free and causing problems.
The size of the new idler pulley will depend on the dimensions of the engine’s drive belt and the available space in the engine. If the pulley proves too wide, it will tear the belt, while a small one cannot transfer enough power to the engine accessories. It helps to measure the width and thickness of the belt beforehand, as well as to make sure the pulley isn’t too big for the engine.
The stronger and tougher a pulley, the better. In general, pick a design with flanges that increase its durability, although some solid pulleys can match their flanged counterparts.
Some pulleys secure the drive belt with grooves that increase the friction between the sheave’s contact surface and the belt. Other designs raise their sides to make sure that the belt stays in touch with the pulley.
Cost of a replacement accessory belt idler pulley
The cost of a replacement accessory belt idler pulley varies from $0.57 to $459.06 at
Important Facts You Need to Know About Accessory Belt Idler Pulley
No one's pulling your leg. A torn drive belt is no joke. If it happens more than once within the first 60,000 kilometers of using a newly installed belt, the problem must be a worn-out Accessory Belt Idler Pulley. You can't take such damage lightly.The accessory belt drives multiple systems under your vehicle's hood; these systems, which include engine cooling, electric and power steering systems, make driving a lot easier and more comfortable. Helping the belt drive all these accessories is the Accessory Belt Idler Pulley.The idler pulley guides the belt's motion and makes sure that
Picking the Right Accessory Belt Idler Pulley
An accessory belt idler pulley is part of a belt and pulley system that drives a car's alternator, power steering, air compressor and other devices. With important parts such as these at stake, it is important to use a pulley of high quality. Constantly running a car would eventually lead to this pulley's deterioration, and that calls for immediate replacement. Here are a few points for consideration when picking a new unit.
The most important factor to consider when picking a new idler pulley is its dimensions. Manufacturers provide pulleys off different sizes. Take into account the width and thickness of the belt drive of your car. A pulley to wide can tear the belt because of too much stress. Install a small pulley and power wouldn't be transferred well to the other devices. Also know the engine space available. Idler pulleys come in many diameters as well so there will be one perfect for your car.
Pulleys must be able to take plenty of load and stress to be able to do its job properly. Some are designed differently to be durable compared to others. A pulley with flanges gives it added strength. This is not to say that solid pulleys are not strong too. Some well-known brands have solid pulleys without flanges that are just as tough.
A pulley is useless without a belt that runs through it. To ensure that a belt stays secure, some pulleys are designed and lined with grooves to provide friction between the pulley surface and the belt. Other replacement parts however are confident enough to use a smooth, groove-free design. Others also use raised sides, like a guardrail, to keep the belt in contact with the pulley's surface.
Installing a new Accessory Belt Idler Pulley
A car's accessory belt idler pulley guides the belt that drives components like the alternator, water pump, air conditioner compressor. A pulley may need repair or replacement when you hear squeaking sounds or if the belts are not aligned anymore. With this guide, you can do that replacement in a few simple steps.
Difficulty level: Easy
- Socket set
- Belt ?tensioner tool
- Replacement idler pulley
- Straight edge metal sheet
Step 1: Before starting the repair, make sure the engine is not running. Find the idler pulley and the belt-tensioner pulley. Depending on your car, the pulleys can be reached by simply opening the hood. Others may be more accessible by lifting the car and removing the engine splash shield. Refer to a sticker on the fan shroud or on the car's manual to help you locate the pulley.
Step 2: Use the belt-tensioner tool to move the belt-tensioner pulley away from the belt to give it some slack. Completely take out the belt off with your free hand. This is a good time to examine the condition of the accessory belt if it is already worn out and needs replacement.
Step 3: Now that the belt is off, remove the bolt of the idler pulley with your socket wrench. Once the bolt is off, remove the pulley off the engine.
Step 4: Insert the new idler pulley afterwards and return the bolt to secure the pulley. Return the belt in the system ensuring that the belt is secure and can be driven by all the pulleys. Finish the job by re-adjusting the belt-tensioner.
Step 5: Get a straight edge metal sheet to ensure that the pulleys and belt are aligned. A misaligned belt can damage the whole system.
This is a quick repair that will take about 30 minutes.