Belt keeps slipping off

Old beltslipped off nrw belt does thessme changed pully

My car has 77000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
The possible causes of this include that the pulleys are not all in the same plane, the pulley on the harmonic balancer has shifted due to a break in the rubber bond, the belt tension is inadequate and/or the bearings on which the pulleys (or accessories) are mounted are worn or seized. To remedy this problem, a diagnostic is performed to figure out which parts have failed and need to be replaced. The belt will have to be removed (so all pulleys can be inspected) and replaced. Even if the existing belt can and will be reused the recommended service to request is a belt diagnostic/replacement and the responding certified mechanic will take it from there. This problem will be resolved very readily as the possible causes are limited in number.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Slipping can be the result of a loss of belt tension (or a weak automatic tensioner) or pulley misalignment. When the belt slips off the track, the friction between the belt and accessory drive pulleys causes the belt to overheat. If you hear a high pitched squealing noise, it`s probably time for a switch.
The serpentine belt need constant tension on the belt to keep it from coming off. If the belt alignment is not aligned then the belt may come off. The tensioner may be out of alignment and not putting enough tension on the belt. Have a mechanic check the tensioner and replace it if needed.
One of the clearest signs that your serpentine belt may need to be replaced is wear and tear to the belt itself. The belt may appear cracked and frayed if it is ready to break. The tread on the belt may also be missing pieces or look flattened, both of which can cause the belt to slip.
If your serpentine belt is failing, you may notice performance issues with your vehicle. The vehicle may frequently overheat. Your air conditioning or power steering may fail to work or not work properly. You may notice your vehicle battery failing to recharge if the alternator is affected by a bad serpentine belt.
Sometimes the belt falls off (rather than breaking) because the pulleys and tensioner are worn, damaged, or misaligned. In that case, simply replacing the belt will not fix the problem.
There are a couple of factors influencing the answer to this question, but on average, your car should be able to run between 20-90 minutes with a broken serpentine belt. The engine will overheat faster without a functioning cooling system on a hot day, so your driving window is less.
What Does a Serpentine Belt Do? As we mentioned early, a serpentine belt delivers power to your alternator, power steering pump, and air conditioning compressor. In some cases, it also supplies power to your water pump. It`s a long, winding rubber band of sorts that is attached to your crank pulley.
Since the serpentine belt helps provide power to cool the engine, a faulty belt can cause the car engine to overheat as the water pump will not turn. As soon as the engine begins to overheat, have it inspected by a mechanic as it can cause a breakdown and cause engine damage if left overheated.
If a belt is not tensioned properly, it will ride too loose or too tight on the pulley. A belt that`s too loose on a pulley will cause slippage, which leads to heat build up from friction. This heat will damage your rubber belts and cause the belts to crack and break.
This damage interferes with the rotation of the belt causing torn belts, or the belt falling off of the engine. Without a belt, stalling and overheating of the engine become commonplace. For auditory cues, squealing noise from the engine belt can be a tell-tale sign.
The main physical difference between an idler pulley and tensioner pulley is a simple adjustable bolt! However, in terms of function and purpose, an idler pulley is responsible for guiding a belt drive in an engine or mechanical system, while a tensioner pulley is responsible for tensioning the drive belt.
The primary distinction between tensioners and idler pulleys is the presence of an adjustable bolt. Tensioners are positioned on the bolt through mounting. Idler pulleys are not mounted to an adjustable bolt.
What causes serpentine belts to break? Too much wear due to heat and friction will cause a serpentine belt to break over time. That`s why regular inspections are vital to making sure this doesn`t happen.
Another symptom of a potential problem with the drive belt tensioner is unusual belt wear. If the drive belt tensioner pulley has any sort of issue it can cause unusual and accelerated wear on the belt. A bad pulley can cause fraying on the edges of the belt, and in severe cases can even cause it to break.
If the dampener is not able to control the tensioner arm, it can cause fluctuations in tension. The belt may oscillate between too little tension and too much tension. The belt will slip and catch, causing noise and vibration.
Of the parts that will eventually need to be replaced in your vehicle, the serpentine belt is one of the most important. How long does a serpentine belt last? Being made of durable rubber, a serpentine belt can last anywhere from around 50,000-100,000 miles.
The short answer is yes, your car will start even if the serpentine belt is broken or missing. To get the car going, the battery sends power to your starter motor. The starter motor provides enough power to get your engine moving and the combustion process started.
If the serpentine belt completely fails and breaks, then your car will break down. In addition, you will notice a loss of power steering, the air conditioning will not work, and the engine will no longer be able to be cooled like it should be.
The serpentine belt is one long, snaking, winding belt that keeps your alternator, power steering pump, air conditioning and—in some cases—your water pump running smoothly and effectively.
A worn timing belt will affect your engine`s starting speed as it is attached to the pulleys that drive the crankshaft. Eventually, the belt can slip on the camshaft drive causing the engine cylinder to open and close at the wrong time.
Serpentine belts are much longer and wider than older V belts. Improved material quality lets belts last much longer. A narrow, deep V-belt design evolved into a wide, flat belt with teeth. Several V belts on older engines have been combined into one serpentine belt on newer engines.
A serpentine belt actually has the ability to transmit the power between your power steering pump, your alternator, air conditioning compressor and water pump, whereas your drive belt simply operates them..
Split belt cover

There`s a lot to be said about the damage that can be caused from forcing a belt onto a pulley or running your v-belts with the incorrect tension, as this is the most common cause for many types of belt damage, including cover splits.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Old belt was sqeeking, new belt does not but it slips off constantley. The old belt stays on though. Why is this?
ANSWER : Check to be sure that the new belt is actually the right part number or, better yet, use an OEM (dealer) belt. Also, be sure the tensioner is the right part number or use an OEM sourced tensioner. Check to be sure that all of the pulleys and accessories (e.g., alternator, water pump, A/C compressor) that are driven by the serpentine belt are all operating in the same plane. It is not unusual for the pulley on the crankshaft harmonic balancer pulley to move (generally outward) relative to its original position. The pulley is rubber bonded and over time can move. If that pulley moves, that means that the belt groves are no longer running in a perfect plane and that alone can cause slipping. If you request serpentine belt inspection a certified Mechanic, dispatched by YourMechanic right to your location, will identify the problem and thence get the issue resolved for you promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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hey i had a belt break while traveling on my 2004 honda pilot. It is the small belt and not the serpentine belt. The mechanic t
ANSWER : Hello. The smaller belt is known as your timing belt, and it works inside the engine to keep mechanical components aligned with each other during the compression cycle. The serpentine belt, which is the big belt, drives the alternator, water pump, AC compressor, and a couple of other components. If the small belt broke it is likely the timing belt. This will cause the car to stall, lights to illuminate, and can even cause serious damage to the engine. Typically replacing a timing belt is a lot more complicated and expensive than replacing a serpentine belt. You may want to receive a second opinion on the car before you go ahead with repairs.

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Timing belt is tight and yet appears to be slipping several teeth when belt is rotated,
ANSWER : This is okay since there are more notches on the belt than the amount on the sprockets. Once you aligned the first time the belt marks will almost never line up perfectly again. The marks are used to put the belt on correctly. They aren’t used as an indicator after the engine is turned again. You should be okay to start the motor as long as timing marks on pulleys line up. If you run into any issues, have a certified technician, like one from YourMechanic, assist you with the replacement of the timing belt.

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Belt keeps on sliding off and breaking the belt.
ANSWER : Hello. Dodge unfortunately had a strange history with this issue in one way or another. The type and quality of belts you are installing may be playing a factor, and you may want to upgrade to a better belt. The type and quality of belt tensioner you installed could also be playing a factor. A smooth belt tensioner surface is subject to the belts sliding off, especially if there is any liquid in the area. If the water pump, oil, or power steering pump are leaking fluid, then the belts are more prone to slipping off and becoming damaged. If you need to have this scoped out, have a local expert, like one from YourMechanic, inspect the belts and make proper adjustments or repairs as necessary.

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Can you change the defected water pump without changing its defected belt (which is the drive belt and only belt in this model of
ANSWER : Hello. Yes you can replace the water pump without replacing the serpentine belt. If the belt is worn, and it breaks while you are driving, you can damage a lot of other components in that area. Typically the price of a serpentine belt is relatively inexpensive. You will have to remove the belt to replace the water pump anyway. Since you are likely going to have to purchase a new pump, we do recommend that you purchase a belt at the same time. You SHOULD replace the belt if it is worn, and this is a perfect time to do it. It is not necessarily required, but you are putting yourself at risk of another break down at a later time. Not to mention if the belt is already worn, manipulating off and back onto the vehicle while changing the water pump can further damage it, and shorten the amount of time its got left. Belts should be replaced before they break, as to the amount of damage they can cause when they do break. Again, you may be able to get away with not replacing the belt right now, but if its as worn as you say, its going to break sooner than later and should be replaced.

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Belts are cracked and need replacing, okay to leave off a/c belt?
ANSWER : Hello. If the belt driving the A/C compressor only drives the A/C compressor and nothing else, you can remove it with no consequences. The fan shroud is not optional equipment however as it has both a cooling system function and a safety function.

Depending on your climate, you might consider diagnosing the A/C system and repairing it. If you use a service such as YourMechanic, it will often be economical enough to do it, particularly if the fault is limited.

Even if the compressor shaft sealing is leaking (would be likely after 25 years), that is fixable in the field. Feel free to contact YourMechanic if you have additional needs relative to this or the replacement of your power steering, alternator, A/C belts.

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Timing Belt Cover replacement and External Belt too.
ANSWER : The parts are touching likely because either the parts were not installed properly or fasteners may be missing or broken. If oil has been leaking, this can cause the seal around the covers to swell as well causing misalignment. Consider hiring an experienced technician like one from YourMechanic who can come out and take a closer inspection of the belt drive to see what is causing the misalignment and offer a more personal diagnosis as well as estimate the proper repairs.

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Belts keeps breaking – 1992 Mercury Capri
ANSWER : Hello. If this all started after the alternator was replaced, then that is more than likely the problem. If the alternator is defective and has an internal bearing failure then this will occur. Also, if the alternator is not mounted correctly, then this can happen. I would have the shop warranty the alternator and that should take care of it. Alternatively, a qualified professional from YourMechanic can come to your home or office to diagnose the recurring alternator problem in person.

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