11 Bad Belt Tensioner Symptoms & Causes

If you are reading this post, it simply means you want to acquired knowledge about the Eleven bad belt tensioner symptoms and causes.

Let’s quickly dish it out.

It is indispensable that engine or machine parts never last forever, so the belt tensioner is no exception. Undoubtedly, it would help if you did not underestimate the belt tensioner’s efficacy, being an integral propeller of any vehicle’s combustion system and putting a regulated amount of pressure on other auxiliary accessories.

Contemporarily, most vehicles’ engine uses a serpentine belt to drive accessories such as air compressor, power steering pump, water pump, and alternator. Practically, unlike the V-belts, which are tensioned as they move the brackets, a serpentine belt, on the other hand, utilizes a spring-loaded tensioner to enhance the accessories’ stay fitted.

Perchance the belt stretches past its lifespan; it becomes too long for the tensioner to work effectively. In any wise, you will need to replace the belt.

In essence, this guide will help put you through as you understand the following specific contents; how to tell if the serpentine belt tensioner is terrible,

how can you tell if your belt tensioner is going bad, 11 bad belt tensioner symptoms, what does a bad belt tensioner sound like, what causes a serpentine belt to break, how long does a serpentine belt last, and much more.

Be patient; let’s get into the gist!

How To Tell If The Serpentine Belt Tensioner Is Bad?

Of the slip or break of the serpentine belt, many damages arise. Although, I will list some common symptoms of a lousy serpentine belt that you should look for to avoid incurring irreparable damage to your engine.

Here you have them, in any case!

  • The displeasing whining sound.
  • Poor driving experiences like overheating, flicking lights, rough idle, acceleration issues, and dimmed headlights.
  • AC compressor issues.
  • The engine vibrates and shakes.

The above are ways you can tell that your engine’s serpentine is faulty.

How Can You Tell If Your Belt Tensioner Is Going Bad?

11 Bad Belt Tensioner Symptoms and causes

The smooth running of your vehicle is on the belt tensioner, which synchronizes other components. So far, to tell or know when your belt tensioner is going bad requires you to be acquitted with these signs and facts below.

Let’s get started as you have them here!

  • Rusting and cracking on the belt tensioner’s arm
  • Worn-out pulley bearings on the belt tensioner.
  • Strange noises like; knocking, rattling, and squealing noises, either from the tensioner’s bearings.
  • Dents, cracks, and chips on the surface of the tensioner’s pulley.
  • Trouble starting your vehicle.
  • Acceleration difficulty.
  • Loss of spring power.

11 Bad Belt Tensioner Symptoms?

A bad belt tensioner can cause numerous problems with your vehicle’s engine. However, the 11 symptoms of a faulty belt tensioner are detailed below.

Here you have them;

1.      Check Engine Light On.

A lousy belt tensioner in your vehicle’s engine would affect the valves, triggering the check engine light on the dashboard. However, the check engine light could mean many issues with your car.

It would help if you used a Scan Tool to check for the trouble code to confirm the problem.

2.      Growling Noise.

The falling of the belt tensioner would as well affect the inner bearing, and the pulley also falls apart. When this situation occurs, you would hear a loud, growling noise.

Make sure to replace a faulty belt tensioner because the growling noise isn’t pleasing.

3.      Engine Fails To Turn Over.

The inability of the belt tensioner to regulate the appropriate amount of tension to the timing belt, which would synchronize with the camshaft and crankshaft, will cause ignition issues.

However, the fuel would not ignite with the air mixture in the cylinder (chamber). In such a situation, you would hear the motor after you turn the key in your ignition, but the engine won’t turn over.

4.      Rapidly Or Unevenly Wearing Of The Serpentine Belt.

When the belt tensioner gets weak, it would be difficult for the serpentine belt to fit suitably on each spinning pulley groove as the alternator, power steering, and others. This irregularity would result in rapid wear and fall out of the place of the serpentine belt.

5.      Misfiring Engine.

The irregular or premature opening and closing of the valve in the combustion chamber, as regards the lousy belt tensioner, would make the engine misfire.

To this, a faulty belt tensioner affects the timing belt, which cannot have the regulated amount of rotation to move the crankshaft and camshaft simultaneously.

6.      Serpentine Belt Slipping Off During Startup.

If your serpentine belt slips off when your engine runs, it indicates that the belt tensioner is faulty and no longer regulates the required tension that the serpentine belt should have.

Even with the engine put off, the pulley and belt tensioner should spin freely without noise. Peradventure, there is noise, and the belt tensioner is faulty.

7.      Failure Of Hydraulic Tensioner.

If there is oil leakage, the belt tensioner is no longer responsible for the suitable amount of tension to the hydraulic belt. So, it is necessary to replace the belt tensioner to avoid oil leakage.

8.      Power Loss.

The failure of the belt tensioner would also affect the serpentine belt and make it slip off or even break. The power steering pump, alternator, and AC compressor would stop functioning immediately. In essence, the engine will lose power.

9.      Overheating Engine.

Though it is the function of the water pump to cool the engine, without mixing words, the inability of the serpentine belt to power the water pump due to the failure of the belt tensioner would cause overheating engine. As the engine keeps running without a handy water pump, the engine is prone to irreparable damage.

10.  Squealing Sound.

The poor adjustment and slipping of the serpentine belt are due to the inappropriate working of the belt tensioner. The malfunction of these belts would bring about a squealing sound which may stop after some time or, if sustained in the engine area of your vehicle, could indicate that the belt tensioner is damaged.

11.  Steering problems

The power steering pump coordinated by the serpentine belt could fail to perform correctly and effectively due to the irregularity of the serpentine belt and the belt tensioner.

To this, it will become difficult to steer your vehicle smoothly. Although, you would have to struggle before you could run, especially if your car has Variable Assist Power Steering.

What Does A Bad Belt Tensioner Sound Like?

Possibly, the sound from a bad belt tensioner isn’t something you would love to hear. So, if your vehicle’s belt tensioner is lousy, it will begin to make a loud, growling noise.

To this effect, this loud growling noise indicates that the bearing inside the belt tensioner has failed and has automatically fallen apart. Perchance, hearing a growling noise would surely be a sign indicating a belt tensioner. Thus, replacement is essential in any case!

What Causes A Serpentine Belt To Break?

A serpentine belt in your vehicle’s engine is a thick strip of grooved metal and rubber that winds around various accessories as it powers these auxiliary systems.

With a magnificent function, you wouldn’t want to have a breakdown of the engine due to a break on the serpentine belt. However, a serpentine belt would break if there is a failure or fault from the belt tensioner.

However, the belt tensioner regulates a certain amount of pressure that keeps the serpentine belt at its proper level of tension. Without this regulated tension to the serpentine belt by the tensioner belt, or if the tensioner belt is faulty, the serpentine and other auxiliary belts would be disengaged and slip.

Thus, you wouldn’t want to experience this!

How Long Does A Serpentine Belt Last?

The lifespan of the serpentine belt would depend on factors such as; the type of quality material used in making the serpentine belt, the vehicle’s mileage, how long the car has existed, and the model of the vehicle because an inspection of vehicles differs by model.

Although, the type of material is the primary factor since it is vital. That said, serpentine belts made of Neoprene rubber which don’t last, are used for older vehicles, but for modern cars, serpentine belts made of Ethylene Propylene Diene Monomer are used, which last longer.

Notwithstanding, an intermediate serpentine belt would last for a mileage range of 55 000 to 90,000 miles. Having high and regular maintenance, you wouldn’t worry about what would make your serpentine belt slip, slap, or even break.


To summarize this informative guide, the worth of the belt tensioner is as crucial as regulating the tensions in synchronization with other vital components of the engine.

Nevertheless, the belt tensioner is not immune to tearing and wearing.

So, it is considered a maintenance procedure for replacing it when wearing and tearing occurs.

Similarly, some frequent symptoms are associated with a bad belt tensioner or a lousy serpentine belt.

Including; strange noises in the form of whirling, rattling, and squealing, overheating of the vehicle’s engine, excessive wear and tear of pulleys, oil leakage, and just a few to mention.

So be watchful of these signs!

Finally, suppose you notice any of these signs detailed in this guide. In that case, I recommend you get a professional mechanic to help diagnose the problem using a Scan Tool, replace worn-out parts, and guesstimate the cost of replacement as well. Take care of your vehicle so that your vehicle will, in turn, take you to your destinations successfully.

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