Wrench Wench has been in love with automotive mechanics for decades. She loves sharing advice with fellow DIY mechs and curious cats.
Is Your Fan Belt Acting Fussy?
Are you concerned that your that your fan belt is on its way to complete disrepair?
Worried that your aging fan belt might be too hard to fix, or that if you drive it longer it might cause your car more trouble?
And are you wondering what the difference is between a fan belt and a serpentine belt? Not to worry, when we say "fan belt" we mean "serpentine belt," too: the serpentine belt is the longer, post-'80s version of the fan belt, as explained below.
Regardless of what drew you to this article, it's the right place for you to be if you're looking to learn about fan belts or serpentine belts, because that's what we're gonna use this space to talk about!
How Can I Tell If My Fan Belt Is Bad?
- Steering your vehicle becomes a wrestling match. If steering has become a little more challenging than it used to be, it might be a sign that your fan belt is on its way out. As the fan belt continues to lose its grip and slip, it makes power steering increasingly difficult, as your car misses the help of the water pump, which also has responsibility for driving the power steering belt.
- The cabin inside your car develops disco fever. As the belt continues to lose its grip, it will struggle to turn the alternator, especially during a cold start. So you may notice that the lights inside the car, and the headlights, go dim when you start your car or whenever there's an extra load on your battery.
- Your car hits the “snooze” button when you try to start it. As your serpentine belt wears down, it has trouble turning the alternator belt consistently, which can lead to no-start problems. Sometimes it gets so bad that it kills your battery, or causes the car to intermittently fail to start, even when the battery is charged up.
- Your vehicle spikes a fever. As your fan belt or serpentine belt breaks down and frays, it won't be able to turn the water pump consistently, which slowly defeats the engine’s cooling systems and causes the temperature to rise more than it should. At first, it'll only be a few degrees and you might just notice off hand that your temp gauge is up a few degrees more than normal. After a while, if the belt lets the water pump slide enough times, the engine will overheat.
- Your serpentine belt is impersonating a snake in the grass. If you find your fan belt is no longer attached to your engine, or is lying on the ground somewhere, that is definitely a sign that it's time to replace your fan belt!
When experienced individually, these signs do not always indicate that your fan belt or serpentine belt needs to be replaced. Many types of electrical and mechanical failures can cause most of these signs and symptoms as well. But seeing two or more of these signs or symptoms together increases the likelihood that your car's fan belt needs your attention.
Why Is My Car Making That Noise?
Old fan belts and serpentine belts are one of the most common parts that cause your car to make some seriously disturbing noises.
- Squealing: If you're noticing a loud squealing or scratching noise coming from under your hood—especially when you first start your car or truck for the day, when you're going up a hill with the heater or A/C on, or when you push on the accelerator pedal—that is your fan belt screaming out: "CHANGE ME!"
- Flapping: If your serpentine belt partially breaks or severely frays, it can start making a "flapping" sound as the broken parts of the belt strike various other things inside the front of the engine compartment.
- Ticking: This is another sound that can occur when small pieces of the belt have separated and are briefly striking other things. It's a small ticking sound that speeds up when you hit the gas.
Signs and Symptoms of a Fan Belt Needing Replacement
|When Starting Up||While Driving||Upon Inspection|
Screeching or squealing noise
Squealing while driving up hills
Flickering or blinking lights
Squealing while A/C or heater is on
Flapping or ticking sounds
Broken or torn strips
Trouble with power steering
Loss of power steering
Missing tread or ribs, or worn out tread
Amperage gauge stays on
Temp gauge shows elevation or the engine overheats
Proper Care & Replacement of Fan Belts: DIY Fan Belt Inspection Video
Common Questions and Answers: Accessory Drive Belts
What Is a Fan Belt? What Does It Do?
- The technical name for a "fan belt" or "serpentine belt" is the accessories drive belt. The reason for this is simple: its job is to turn several pulleys and gears that utilize the energy and inertia from the crankshaft and starter to turn and power up different accessories and important functions in your car. These include, but are not limited to, harnessing energy from your alternator which is sent back to your battery and keeps it charged, activating your power steering which makes your vehicle way easier to steer, and turning your water pump to keep your engine cool.
Why Does My Car Need a Fan Belt or Serpentine Belt?
- Your fan belt drives the accessories and main functions of your vehicle. Without your belt, or with a very worn belt, you couldn't use power steering, your car would overheat all the time, and many more challenges would pop up.
What Is the Difference Between a Fan Belt and a Serpentine Belt?
- Fan Belt: "Fan belt" is kind of a colloquialism these days. Fan belts are more commonly found in vehicles built before the 1990's when serpentine belts started to replace them. In theses older models, "fan belts" are usually paired with other belts that together form a "V" shape around your drive pulleys and gears. It is very common to find classic cars that had a three-belt setup including one belt to run the coolant fan.
- Serpentine Belt: Just like the old "V Belts," the serpentine belt is designed to drive all the accessories in your vehicle. The only true difference between a serpentine belt and a fan belt is that a serpentine belt is designed to manage ALL of your accessories using only one belt that loops and winds around the front of your engine like a long black snake.
- The video below explains the difference between a fan belt and a serpentine belt.
Is a Fan Belt or Serpentine Belt Different From a Timing Belt?
- Yes, the timing belt is hidden inside the engine, has ribs on it, keeps the engine timing correct, stops the engine if it breaks, and is not nearly as accessible and serviceable as the fan belt or serpentine belt.
How Often Should I Inspect My Fan Belt?
- Once a month is best, though if you inspect your belts whenever you take your vehicle in for an oil change, you'll usually be safe. Serpentine belts, which are much more commonly found in cars these days, are designed to last much longer then their predecessors. You shouldn't need to replace them more than every four or five years or every 60,000-100,000 miles.
What Should I Look for When Inspecting My Belts?
- Cracking: Check every side of the belt for any cracking or peeling. If you find any, that means it's time to replace your belt before it breaks on you.
- Fraying: As a serpentine and fan belt start to get older, they can start to move a little in their track. As this happens, the sides of the belt can become more vulnerable or can sometimes start rubbing against other belts or parts of the engine block, which then causes the outer edges of the belt to fray. The more fraying you have or that you allow to form, the closer you get to having your belt bust on you while driving.
- Worn Tread: There is a tread on the underside of your belt and just like a tire, the tread will wear down over time. When you inspect the belt, you want to see how worn the tread is. The flatter and more faded it is, the more likely it will cause you unnecessary transportation headaches.
- Malformation: Look for any melted, dented or malformed areas on the belt. The thickness and texture should be uniform across the entire belt.
- Tension: How taught is your belt? You should be able to push down a little bit on a serpentine or fan belt, though there should never be enough "give" that you're able to easily slide your belt on or off its track. There should be enough tension to keep it in place so that it won't slip tracks or fall off completely.
How Long Can I Drive a Car if the Fan Belt Is Whining or Squealing?
- With over 30 years of combined experience, my fiance and primary business partner and I both agree, you shouldn't expect to go more than a week with a failing fan belt or serpentine belt before it is likely to break. That is not to say that there aren't plenty of people who've managed to drive their vehicles with failing fan belts for much longer, but they are all literally exceptions to the rule.
What's the Worst Thing That Can Happen If I Keep Driving and It Breaks?
- Your car could stall if the alternator or battery is already low.
- Your motor could overheat if the car doesn't stall.
- The loss of power steering at high speeds could cause a collision.
My Car Isn't Starting, Could It Be My Fan Belt?
- Yes! If your fan belt has inconsistently done it's job for a while, it could cause the battery to slowly drain from not receiving enough energy. Likewise, if your fan belt or serpentine belt breaks or falls off, that would prevent your car from starting even if you were able to drive home after losing the belt.
Can I Still Drive My Car Without a Serpentine Belt or Fan Belt?
- So long as the vehicle is still running when the belt falls off, breaks, or is removed, and the alternator still has a good charge, you should be able to safely drive your car home or to a shop. You might even get a few more starts out of it after then, though your battery will quickly die from not being recharged by the alternator through the drive belts.
My Ammeter Shows My Battery Isn't Charging at the Right Amperage. Could It Be My Fan Belt or Serpentine Belt?
- Yes, if it's not gripping enough to charge the battery back up. This failure to charge can ruin a battery, starter and alternator also, requiring all to be replaced.
How Hard Is It to Change a Fan Belt or Serpentine Belt? Does It Require a Lot of Tools?
- No, and no. There are always exceptions, but most cars made between 1920 and 2018 should have a super-simple setup, whether that's v-belts or a serpentine belt. In most cases, you will only need one breaker bar or a large wrench with a square peg that can fit into the center of the tensioner pulley, so you can pull the tensioner pulley back and release the belt. In older models you'll use a socket wrench to remove a few bolts near the alternator. Either way, the project is one of the most simple DIY repairs you can take on, which is why I usually recommend it for first time DIY'ers looking to get started, drivers who want a taste of what it's like for their mechanic, or drivers who want to make sure they aren't getting completely ripped off labor-wise.
Do You Do It Yourself or Take It to a Shop?
Trying to decide if this repair is worth your personal time and attention versus it being time to just bite the bullet and take your car into a shop to get that fan belt changed?
Below I've created a handy table with some starter "pros" and "cons" that usually help my clients decide whether they'd like to fix something themselves, have me fix it, or take it into a shop.
Use it to get your priorities straight if you're not yet sure which choice you want to make.
Do you enjoy DIY mechanic projects?
How busy is your life right now? Do you doubt you have the time to work on your own car?
Do you feel a sense of accomplishment from taking care of your own belongings?
Does thinking about getting greasy or dirty make you queasy or hesitant?
Have you had one or more bad experiences taking your vehicle into shops before?
Do you even own a tool?
Do you need to prove to someone else that you can fix things yourself?
Does the idea of buying the right tools for this job feel daunting?
Are you new to DIY mechanic projects? Would you like to start with a very simple starter repair?
Do you trust yourself or any of your friends to fix your vehicle properly?
Can you afford to pay the shop price to fix your car?
Would you prefer the benefits of guaranteed work or warranties over any benefits of doing it yourself?
Are your looking for a cool science project for school that would include learning about weights, pulleys, belts, and gears?
Can you afford the costs of shop repair?
Do you have another vehicle you can drive while you learn how to repair this one?
Do you need your car fixed and back to you in a few hours or a day?
Are you naturally mechanically minded, or do you feel you could "figure things out" if you didn't have any help?
Does the idea of having to open your hood and secure the hood prop make you feel overwhelmed? What about looking at the engine?
Fan belt and serpentine belt replacements are FANTASTIC first-timer projects. They also make great father-son-type starter projects. The task usually only requires the removal or loosening of a few bolts to remove the belt and replace it. There's very little to it, and it's very easy to navigate through the project even if you know almost nothing about cars. It's a great confidence-building maintenance task for any budding DIY mechanics out there."
— Wrench Wench
Issues That Can Lead to a False Diagnosis of Failing Fan Belt
- Misaligned pulleys: In some cases when you see all of these signs and symptoms, it could be that one or more of your pulleys is misaligned and causing the serpentine belt to stretch more than it is meant to, or sit more loosely than it should. This can happen from something as simple as not seating the alternator back into place correctly after removing it to loosen up the belt.
- Humidity: If the humidity in your geographic area rises, or you drive your car out of a low-humidity environment and into a high-humidity one, the moisture in the air can cause your belt to act up or slip.
- Wet surfaces: Sometimes right after it rains especially hard, you drive through a large puddle, or you visit the car wash, you might notice many of the above signs. It is common to freak out at this moment and think that there is something permanently wrong with the car.
- Frozen pulley: I've seen this much more often in older cars with disconnected AC units or disconnected smog pumps, though it could happen in any car. It's easy to confuse a stuck pulley with a failing fan belt, so make sure you inspect everything thoroughly while making your diagnosis!
- Bad tensioner pulley: Bad tensioner pulleys are the problem most commonly misdiagnosed as a bad fan belt or serpentine belt. This situation doesn't happen often, though, as most tensioner pulleys are designed to last over 200,000 miles.
Decided to DIY?
Fixing your fan belt is super simple. In another article we'll go through removing and replacing fan belts step by step. Until then, check out these two great videos below that will walk you through the DIY process if you've decided you're brave enough for this super-simple repair.
How to Replace an Alternator Belt (Same as Fan Belt)
How to Replace a Serpentine Belt
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2018 Wrench Wench
Comment Below With Your Stories & Experiences!
WheelScene from U.S.A. on February 09, 2018:
Thanks for sharing such a comprehensive article!