Serpentine Belt Buyer’s Guide
- The serpentine belt is a long belt that loops around a complicated system of pulleys to power the alternator, air conditioning system, power steering system, and the water pump.
- Although serpentine belts are made with high-grade, sturdy rubber, they’re still bound to wear out due to constant exposure to heat and friction. The average lifespan of a serpentine belt ranges between 50,000 to 100,000 miles or about five years and up.
- Common signs of a failing serpentine belt are physical damage, whining or squealing noises, air conditioning and power steering issues, engine overheating, and electrical systems failure.
- If you’re buying a serpentine belt by itself, the cost would be around $10 to $80. Replacement serpentine belt kits which typically include the serpentine belt, the tensioner, and two idler pulleys costs around $100 to $300.
Your car is made up of hundreds of complex interconnected parts. These various electrical and mechanical components work together to make your car run as it should. One of these complex components that is absolutely vital to your car is the serpentine belt.
What is a Serpentine Belt?
The serpentine belt, also called the drive belt or accessory drive belt, is a long, “endless” belt that loops across a complicated system of pulleys to power various parts of your vehicle. In most cases, the serpentine belt is responsible for providing power to the alternator, air conditioning system, power steering system, and the water pump.
Since the serpentine belt performs a crucial function for several important systems in your vehicle, failure of this component will cause problems in other systems as well. When the serpentine belt fails, your engine accessories won’t spin at the right speed resulting in loss of power. This means that your electrical system will fail and your air conditioning and power steering systems will stop working. If your serpentine belt powers your water pump, the water pump will stop working as well causing your engine to overheat.
Serpentine Belt Location
The exact location of the serpentine belt depends on the engine layout of your vehicle. In general, it’s located beside the engine and can be seen easily when you pop the hood of your vehicle open. Since the belt snakes its way across a system of pulleys, it’s quite easy to recognize.
Other Types of Vehicle Belts
Older cars used to have multiple V-belts or fan belts to control various systems. These belts are now replaced by the singular serpentine belt in modern vehicles. Some cars also have timing belts. The timing belt is usually covered and looks quite different from the serpentine belt, so you don’t have to worry about confusing the two.
How Long Does a Serpentine Belt Last?
Although serpentine belts are made with high-grade, sturdy rubber, they’re still bound to wear out due to constant exposure to heat and friction. Many mechanics agree that the average lifespan of a serpentine belt ranges between 50,000 to 100,000 miles or about five years and up.
Checking if your serpentine belt needs to be replaced after 50,000 miles or five years, whichever comes first, is advisable. This is to ensure that the belt will always be in excellent working condition. If you don’t want to routinely replace it after the recommended mileage, make sure you take the necessary precautions. After 50,000 miles, it’s essential that you regularly check the serpentine belt for signs of damage. The important thing to remember is that the serpentine belt must be replaced before it fails completely.
Signs of a Failing Serpentine Belt
Knowing how to tell if a serpentine belt is bad can help you avoid unexpected belt failure. Here are some common signs of a failing serpentine belt:
Visible Physical Damage
Serpentine belts are exposed to heat and friction and are constantly stretched as well. With prolonged use, the rubber will start showing cracks, missing chunks, missing ribs, or frayed edges. Cracks and missing chunks are easy enough to recognize, and fraying usually happens on the edges of the belt.
Serpentine belts might also develop a shiny or glazed look. Glazing happens when the serpentine belt is constantly slipping from one of the pulleys. These are all signs that the belt is worn out and needs to be replaced soon.
Whining or Squealing Noises
Strange whining or squealing noises under the hood of your vehicle will alert you to a failing serpentine belt as well. This is usually caused by a serpentine belt that keeps on slipping, low pressure from the tensioner, or issues with your belt and pulleys not working correctly. When you hear whining, squealing, or chirping noises coming from the front of your car, make sure to check your serpentine belt for any issues.
Air Conditioning and Power Steering Issues
If you’re experiencing issues with your air conditioning and power steering system, it could be a result of your serpentine belt slipping. If your serpentine belt completely fails and breaks, your air conditioning and power steering system will stop functioning. This can cause serious safety issues when the belt breaks while you’re driving. It’s absolutely essential to avoid this scenario. Make sure to check your serpentine belt at once if you notice that your AC is not functioning normally or if you experience loss of power steering.
Electrical Systems Failure
Since the serpentine belt also powers the alternator, failures in your electrical system could also point to a worn out serpentine belt.
If your car’s serpentine belt also powers the cooling system or water pump, its failure can also result in your engine overheating.
When looking for signs of damage to your serpentine belt, it’s also a good idea to check related components such as the tensioner, accessory pulleys, and idler pulleys. This will help you ensure that you’re replacing all worn out components in one go.
Choosing a Replacement Serpentine Belt
Finding the right fit is the most important factor when choosing a replacement serpentine belt. Make sure to check your owner’s manual to find a replacement belt that directly fits your vehicle.
If you want to have a wider range of choices, consider going with an OE replacement for your serpentine belt. OE replacement car parts usually work similar to the original factory-issued component that you’re trying to replace. In some cases, OE replacement parts or aftermarket parts actually provide a better option compared to an OEM part. For serpentine belts, many aftermarket car parts manufacturers use high-grade materials and advanced manufacturing methods to create belts that are highly heat-resistant and last longer than the original part.
How Much Does It Cost To Replace a Serpentine Belt?
If you’re buying a serpentine belt by itself, the cost would be around $10 to $80. Replacement serpentine belt kits which typically include the serpentine belt, the tensioner, and two idler pulleys costs around $100 to $300.
Tips to Bear in Mind When Purchasing a Serpentine Belt
The performance of your engine accessories—the water pump, alternator, and fan—is directly affected by the condition of the serpentine belt. Yes, even a 5% loss of belt materials or a slight damage on it can have an effect on the operation of these accessories. This is why it’s important to regularly check your belt even if it doesn’t require any maintenance.
A bad belt can give you drivability problems. And once it snaps, it can leave you and your passengers stranded in the middle of nowhere. So as soon as you notice signs of a bad belt, don’t think twice in replacing it. When looking for replacement, here are some tips:
Make sure to get the right replacement.
When purchasing online, be extra careful in making your choice because you won’t be able to scrutinize the product personally. To be sure you’ll get the right replacement, check out the unit’s part number and make sure it is designed to replace your old belt’s part number.
This also particularly helpful if you’re purchasing a serpentine belt only. By getting an exact replacement for your stock, you can be sure that it’s compatible with the tensioner, pulley, engine, and all the accessories that should be driven by the belt.
Besides the part number, you should also pay particular attention to the number of grooves, ribs, as well as the width of the belt and make sure the specs of the replacement unit match all the specs of the stock.
Buy new gaskets, gasket adhesive, and other things you may need for the installation.
To save time and money from making multiple purchases, it will be wise to include gaskets, adhesive, as well as all the hardware you may need when installing the belt along with your serpentine belt purchase. If the tensioner has defects, you should replace it as well. You can even consider getting a kit to be sure that all the components are compatible with one another.
Purchase a belt that’s one size smaller than your old serpentine belt.
It isn’t a good idea to install a belt that’s either too big or too small. If you can’t find your manual and there’s no way for you to know the exact length of the belt, measure it’s length with a string and get a belt that’s one size smaller than the measurement you’ve obtained. If you’ve measured 80 inches, get a 79-½-inch replacement belt. This is because the belt has tension while the string doesn’t.
How to Visually Inspect the Serpentine Belt
Unlike the v-belt that requires periodic adjustment, serpentine belts need no maintenance at all. But that doesn’t mean they shouldn’t be checked regularly. At every oil change, it’s a good idea to inspect the condition of the serpentine belt. By doing so, you can catch a bad belt right before it snaps or fix any damage that may shorten the belt’s service life.
Here are the steps on how to do visual inspection on your serpentine belt:
Difficulty level: Easy
Step 1: Consult your owner’s manual to find the belt’s location and to be familiar with its specs. Take note of how the belt looks like and what components are powered by it. Prop the hood up and look for the belt. You may need a flashlight if your work area isn’t well-lit for you to clearly see the condition of the belt.
Step 2: Look for oil on the serpentine belt. The belt’s back or smooth side is what drives the vehicle’s water pump. When this side of the belt gets soaked or glazed with oil, it will definitely slip and fail to keep the engine cool. Also, when there’s oil in the serpentine belt, there could be some kind of a leak somewhere. You have to do some more troubleshooting to find out where the oil is coming from and have it fixed.
Step 3: Check for tears or abrasions. If there’s any, that’s an indication that the belt is rubbing against a pulley flange or a bolt as it runs. The tears will get more serious as the belt gets older. If this is the case with your ride, smoothen out the pulley flange or bend the component that rubs with the belt to get it out of the belt’s way.
Step 4: Search for bumps or pinholes as these are signs that debris and dirt have found their way into the area between the belt and the pulleys. To inspect for missing chunks of the belt’s ribs, you can turn it around and crank the engine to reveal other sections of the belt for inspection. If there are a few, widely spaced chunks, there’s no need for you to worry. But if they are many and are close to each other, that calls for a replacement.
Step 5: Don’t ignore cracks. While hairline cracks are normal, they shouldn’t be deep enough to get into the backing or the flat side of the serpentine belt. If the crack is deep, then you must have your belt replaced. Also, if the cracks are 3mm apart, these are indications that your serpentine belt has already seen better days.