How To Stop Serpentine Belt from Squeaking?

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If you notice a loud squealing noise coming from beneath your vehicle’s hood, it’s highly probable that a belt is slipping through the pulleys. Most modern automobiles use one, continuous belt which wraps around several pulleys on various parts on the front-end part of the engine.

This belt is often used to link the water pump, power steering pump, alternator, and air pressure compressor. While older automobiles are not equipped with serpentine belts, they do feature distinct V-belts that power various systems. When these belts slip, its ensuing friction will produce a sharp squealing. 

In this guide, we shall be discussing different methods to make a serpentine belt stop squeaking.

how to make serpentine belt stop squeaking

Understanding Serpentine Belt Noises

When you hear noise from a recently installed serpentine belt, it serves as a warning sign for issues in the engine’s front end drive system. Just like a “check engine” light signifies a problem with the engine, serpentine belt noise indicates an issue with the belt drive system. Surprisingly, the belt itself is usually not the source of the problem.

There are two most common noises produced by a serpentine belt.

  • Serpentine belt squealing noise
  • Serpentine belt chirping noise

Serpentine Belt Chirping Noise

The chirping noise consists of a sequence of sharp, intermittent, and rhythmical sounds. As the belt speed rises, the pitch and volume remain consistent, explaining why you hear a persistent chirping sound when accelerating.

There are six primary reasons for this chirping noise:

  • Pulley misalignment, which is the leading cause of such noise.
  • Incorrect installation.
  • Worn belt ribs.
  • Faulty pulley bearings, resulting in wobbling or excessive free movement.
  • Contamination from substances like power steering fluid, engine oil, coolant, or belt dressing.
  • The use of a low-quality belt in the installation.

Serpentine Belt Squealing Noise

The squeal is characterized by a high-pitched sound that lasts for several seconds, with potential fluctuations in volume but not in pitch.

The top three reasons for this squeal are as follows:

  • Inadequate belt tension, which can result from low installation tension, a stretched belt, extensive belt wear, deterioration of tension springs, or the use of a belt that is too long.
  • Increased drag on accessory/idler pulleys due to seized bearings or accessory failure/lock-up.
  • Belt contamination caused by exposure to substances like belt dressing, oil, antifreeze, or other chemicals.

What Causes a Serpentine Belt to Squeak?

Mainly, squeals occur when the serpentine cannot stay in position in any of the pulleys. The most common reason why the serpentine belt glides out of position is moisture on the inside part.

So, where could this moisture be coming from? Mostly from leaking engine accessories. If any of the accessories is leaking, the fluid will be splashed onto the belt, causing it to slide off the pulleys. Other common reasons include:

Improper Installation: If you notice the squeal right after installing a new serpentine belt, likely, the process was not done right. You should ensure that the mechanic tensions the belt and adequately re-tensions a few minutes after starting the engine to ensure that it’s tight enough to stay in position.

Wear and Tear: Rubber belts are prone to wear and tear, just like most things in life. Over time, your car’s serpentine belt may become glazed, cracked, or brittle.

This reduces its overall effectiveness, and eventually, the belt will start to slip from the pulley system, resulting in that annoying squeal. The grooves may also get too deep, and this can also cause unpleasant noises.

Extreme Weather: Extreme weather reduces the serpentine belt’s stiffness. You will notice the squeal when you start the car, and the sound will disappear after driving a few miles or when the weather improves.

Misaligned Tension/Pulley: If a misaligned belt is not the problem, the tensioner or pulley system may not be aligned well. A mechanic can tell which parts are not appropriately placed and quickly put them back to the right position through a simple inspection.

Damaged or worn-out pulleys can also lead to belt squeaking. If the pulleys have damaged bearings or are not in good condition, they may not rotate smoothly, causing the belt to slip and make noise.

Worn Tensioner or Idler Pulley: The tensioner and idler pulleys are responsible for maintaining the proper tension on the serpentine belt. If these components wear out or have damaged bearings, they may not apply sufficient tension on the belt, leading to squeaking.

How To Stop Belt Squeal/ Stop A Squeaky Belt

How To Make Serpentine Belt Stop Squeaking

1. Identify the Source of the Noise

The first step in fixing the squeak is to locate it. This entails turning on the vehicle and investigating the noise, which may involve a variety of approaches depending on how old your automobile is.

A belt that creaks is probably slipping. As a result, since timing belts contain teeth, they can never be at fault. They have teeth to prevent slippage; otherwise, the internal timing of the engine would be altered, and multiple costly components would begin colliding against one another, resulting in engine failure.

In 90% of instances, the auxiliary belt will be the real the culprit. This belt is responsible for powering the air conditioner, alternator, water pump, and other components. The fan belt is another potential culprit. Modern automobiles typically have electric fans. On older vehicles, though, the fan is operated by a belt.

2. Check The Belt for Wear

Wear and tear on a serpentine belt are pretty apparent. If you notice that the belt has slipped on a pulley or two, it indicates that you need a new belt.

You may also notice wear signs on the belt edges. If the belt is worn out, start making plans to replace it before it fails. A worn belt will also be much thinner than a new one, and the grooves get deeper. You may need a belt gauge to check the depth of the tracks.

A water test is also perfect for diagnosing if the squeak is wear-related. This test should take you about 5 minutes, and all you need is a spray bottle.

Turn the car engine on, turn it to low-idle and use a spray bottle to squirt water on the inside part of your belt. If you notice an increase in noise, the belt may be worn or loose. You may want to wear some goggles when doing this test as some of the water may splash back at you.

3. Check For Spills

If the belt looks shiny, there may be a fluid contaminating it. Check for oil, coolant, or grease leaks or spills on the belt. It’s advisable to quickly stop the spill as these contaminants will interfere with the belt’s function and deteriorate the material.

4. Check the Pulley Alignment

To check the pulley alignment, you must loosen or remove the belt. Only proceed with this step if you know what you are doing. Once the belt is off, the pulleys should spin quietly and freely. Any friction or grinding noise indicates that the bearings are damaged or worn and need to be replaced.

To be sure that the bearings are a problem, mark the edge or face of the pulley with a grease pencil or chalk before reattaching the belt.

Start the engine and check if the mark and the squeaking noise align.

If they do, the bearings are worn out. It may not be all the bearings that need replacement. Your mechanic should quickly identify the defective one and replace it. If the bearings are OK, the pulley may be misaligned. Since the pulleys are usually tightly secured to the engine system, you need a bit of strength and some hardware to push it back in position.

5. Dress the Serpentine Belt

The first thing to do is dress the belt once you’ve located the cause of the noise. You can purchase belt dressing, which both moisturizes and protects the belt. All you have to do is spray the entire belt—not just a portion of it— when the engine is running. Ideally this should quiet down the noise.

A perfect example I would highly recommend is Permatex 80073 Belt Dressing and Conditioner.

This is an aerosol dressing that will improve friction on the ribbed side of the serpentine belt. The spray may also remove water and contaminants that may be causing the squeak. However, you must remember that the dressing is a temporary solution.

The situation will only get worse if you do not address the underlying problem. Also, note that the lubricant may make the rubber stretch or slip, so the problem may worsen when its friction effect wears off.

6. Tighten the Belt and Replace

The tensioner is responsible for securing the belt firmly in position. Refer to your Haynes manual to locate the tensioner’s position. You should be able to loosen the bolt that secures it, potentially requiring a gentle approach with a pry bar, to adjust the tension on the belt.

Increasing tension reduces slack, resulting in a quieter operation. Once you’ve made the necessary adjustments, tighten the bolt again and listen to check if the noise has disappeared.

If the serpentine belt is worn out beyond repair, then I would highly recommend you to replace it with a new quiet serpentine belt.

Will Belt Dressing Stop Squeal?

Belt dressing is a product designed to temporarily reduce or eliminate squealing noises from drive belts, such as serpentine belts or V-belts, by adding a tacky substance to the belt surface. It can be effective in some cases, but it’s important to understand that it is a temporary solution and not a long-term fix.

Belt dressing can help if the squealing is caused by slip between the belt and the pulleys due to a lack of tension or if the belt is glazed and smooth. The tacky substance in the dressing can provide additional grip, reducing the slip and noise. However, it does not address the underlying issues that may be causing the squealing, such as worn-out belts, misaligned pulleys, or improper belt tension.

While belt dressing can provide a temporary solution to belt squealing, it’s essential to address the root cause of the problem. Regular maintenance, including proper tensioning, alignment, and keeping the belt and pulleys clean, is the best way to prevent belt noise. If the belts are significantly worn or damaged, it’s best to replace them with new ones.

How To Fix A Squeaky Belt With Soap?

Using soap to fix a squeaky belt is a temporary solution and may not be the best way to address the problem. Squeaky belts are often caused by friction between the belt and the pulleys or other components of the system.

Applying soap can provide temporary lubrication and reduce the noise, but it won’t address the underlying issue, which may be belt wear, misalignment, or tension problems. It’s essential to identify and fix the root cause of the squeak for a long-lasting solution.

Ensure the engine is off and the vehicle is in a safe, stationary position. You can use a bar of soap or liquid soap for this. Rub the soap directly onto the surface of the belt while turning the belt manually or running the engine briefly to allow the soap to distribute evenly. Start the engine and listen for any improvement in the squeaking noise. If it has decreased, the soap has temporarily lubricated the belt.

Be aware that the soap’s lubricating effect may not last very long, and the squeak may return. It’s best to address the root cause of the squeak for a more permanent solution.

How to Fix a Squealing Serpentine Belt with WD40

If you notice a squealing sound coming from your serpentine belt, you can apply WD-40 as a temporary solution. Squealing often occurs due to excess moisture on the ribbed side of the belt, causing it to slip. WD-40 is effective in removing moisture, which can help eliminate the squealing. Be sure to wear safety glasses when applying WD-40 to the belt and use short bursts to lightly cover it without over-saturating. Applying too much WD-40 can potentially damage the belt.

If the squealing returns shortly after applying WD-40, it’s a sign that you should consider replacing the belt promptly. The serpentine belt drives various engine accessories, so a malfunctioning belt can disrupt the functioning of your vehicle. You can use WD-40 to temporarily alleviate the issue and then seek professional assistance to have the belt replaced.

WD-40 should only be employed as a temporary remedy for a squealing serpentine belt due to its potential to harm the belt. This product is primarily petroleum-based and consists of approximately 50% Stoddard solvent, 25% light oil, and 12% to 18% LVP Aliphatic Hydrocarbon, with an undisclosed secret ingredient.

Petroleum-based substances have the propensity to cause rubber to expand and deteriorate, making them unsuitable unless you intend to replace the belt. When lubricating rubber components, it is advisable to utilize silicone or a dry Teflon lubricant.

While spraying WD-40 on the serpentine belt can temporarily silence the squealing, it does not address the root problem and may contribute to belt damage. Its usage is only warranted when you have plans to replace the belt and desire a temporary cessation of the squealing.

On How to Fix Noisy Serpentine Belt

In conclusion, addressing a noisy serpentine belt is essential for maintaining your vehicle’s performance and ensuring a quiet, smooth ride. A squealing or chirping serpentine belt can be caused by various factors, including wear and tear, misalignment, or inadequate tension. We’ve explored several methods to fix a noisy serpentine belt, whether it’s using belt dressing, soap, or WD-40 as temporary solutions.

However, it’s important to remember that these are just temporary fixes and should not substitute for proper maintenance and addressing the underlying issues. Regular inspections and maintenance, such as checking for wear and tear, adjusting belt tension, and realigning pulleys, are crucial for long-term serpentine belt health.

If you find that the squealing persists or reoccurs shortly after applying these quick fixes, it’s a sign that you should consider a belt replacement. The serpentine belt plays a crucial role in powering various engine accessories, and a malfunctioning belt can lead to more significant problems down the road.

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