Serpentine vs. timing belt (drive vs. timing belt): Are they the same?

What is a serpentine belt?

The serpentine belt (sometimes drive, fan, alternator, or accessory belt) is a long piece of car equipment made from rubber. It coils around the vital parts of your car engine like a serpent, hence the name. Its main purpose is to deliver power to these parts. It includes the power steering pump, A/C compressor, water pump, and alternator.

serpentine belt

While modern vehicles largely sport a single belt wrapped around the components, it used to be common for manufacturers to utilize more than just the one to deliver power to them. These numerous so-called V-belts functioned independently of one another.

It was advantageous in certain aspects, such as when one of them broke. Because they weren’t linked, the other components not linked to the broken belt retained their functionality. Moreover, they were far less likely to slip.

On the other hand, using them meant filling up much more space in the engine. It was ultimately the cause that led to their demise. Nowadays, you are likely to find them solely in older car models. Their replacement might pose an extra challenge as they are not as easy to get ahold of.

Although the usage of just one belt has revolutionized the car industry in terms of efficiency, any damage to it ultimately renders all of the accessories inoperable.

While you can drive your car without air conditioning, the lack of power steering can truly be felt. This system facilitates the steering wheel/car wheels coordination. Bereft of its aid, you will find it far more arduous to operate it.

drive belt

Moreover, your car battery’s hours are numbered the moment the serpentine belt snaps. With the link between the alternator and the battery broken, it will fail to recharge. Innocuous as it sounds, it renders your vehicle dangerous to drive. Once the battery has run its course, headlights, indoor lighting, and power locks are just some examples of what stops functioning. Worse, you cannot start your car when your battery is out of juice.

You probably did not know such a thing as a water pump existed. Though not particularly renowned, it is responsible for cooling down your car engine while it does the heavy lifting. Non-functional water pump leads to your engine overheating. Your vehicle’s safety may be threatened if exposed to high temperatures for too long.

These components may be greatly damaged if you drive your vehicle with a bad belt for too long.

Durable as it may be, even your serpentine belt is not immune to the passage of time. It will fall prey to constant friction and heat exposure. Thus, it is prudent to replace it every 50,000 to 100,000 miles. Otherwise, it may break down while you are driving somewhere. It ultimately means pointless expenses that could have been avoided by regular maintenance.

serpentine belt on white background

If you are unsure when you last had it replaced, odd engine noises and failure of the components mentioned above suggest that your car is overdue for a check-up.

What is a timing belt?

timing belt

The timing belt is located inside the car engine, meaning it is not visible to the naked eye when you open the hood. It is made of rubber and features hard teeth that fall into the cogwheels of the crankshaft and the camshafts.

Here, it synchronizes the movements of all the parts which move in the engine. As you may know, most cars’ engines run utilizing the four-stroke cycle:

  • intake
  • compression
  • combustion
  • and exhaust.

A correctly functioning belt guarantees that the intake and exhaust valves open and close properly during each of the strokes.

Untimely opening of either of these valves leads to less power delivered to the wheels, which is undesirable. In case the timing belt is very worn-out, the haphazard operation of the engine components can lead to severe damage to your vehicle. Repairs of this caliber can be quite expensive.

It is important to note that your car may lack a timing belt. Instead, it may sport something called a timing chain. It serves the same purpose; the only difference is the material. While timing belts are made of rubber, timing chains, as you may suspect, are made of metal. The timing belt was invented as a quieter alternative to the timing chain, though the chains have been resurgent in recent years due to their greater longevity.

Which one may be found in your car depends on your model, and you can find the information in your manual. Both need to be replaced regularly, though chains less frequently.

Serpentine vs. timing belt: differences to know about

A serpentine belt is not to be confused with a timing belt. It contains numerous grooves in the shape of the letter V while the timing belt is speckled with much more pronounced teeth which fit into the cogwheels of the crankshaft and camshaft.

The serpentine belt is clearly visible, coiling around various components of the car engine when you lift the hood. However, the timing belt lurks much deeper in the machine. You will not be able to see it without taking the engine apart.

These two components also perform two separate functions. While the serpentine belt serves as a conductor of power to your engine components, the timing belt is responsible for synchronizing the moving parts of your engine during each stroke of the cycle.

The prices for their replacement are vastly different as well. Replacing your serpentine belt will cost you $25 to $200, depending on whether you choose to do it yourself or by a professional. The timing belt is much more expensive to replace, with prices ranging from $300 to $1000.

The reason behind what seems like exorbitant sums are that it is not as accessible. Because it is hidden deeper in the engine, you are unlikely to handle this task yourself. The labor cost is thus greater as well. If left unchecked, the damage caused is much greater and costlier.

However, there are some things both share. Neither one is resistant to age. Replacing them both is necessary if you wish to avoid pointless repair expenses. If you neglect this maintenance responsibility, you can expect to pay far more for car repairs than you would for the replacement only.

Frequently Asked Questions

Is a serpentine belt the same as a timing belt?

Although you are advised to replace both simultaneously, they are two independent engine components. The serpentine belt is found outside the engine itself. It makes it more accessible for repair than the timing belt, which is found deeper inside.

Their functions are disparate, with the serpentine belt delivering power to components such as the power steering pump, air conditioning, and alternator. On the other hand, the timing belt ensures synchronization of the pistons and valves during the four-stroke cycle.

They differ in terms of physical appearance as well. The timing belt has many teeth on its surface complementary to the crankshaft and camshaft cogwheels. The serpentine belt lacks these features.

Replacement costs of the serpentine belt are more affordable than those of the timing belt, the lowest prices being $25 and $300, respectively.

How much does it cost to replace a drive belt?

The replacement cost varies greatly depending on whether you choose to do it yourself or have it done by a professional.

The serpentine belt alone is a relatively cheap component, ranging from $25 to $75. The task itself is relatively simple, and anyone at least a little handy can perform it with the aid of the Internet.

Naturally, opting to have a mechanic do it for you is more expensive. Due to the added labor costs, we are looking at prices from $100 to $200.

In conclusion, the DIY route is better if you are confident in your abilities as it is cheaper. On the other hand, having a professional do the job guarantees seamless replacement and saves you some time. Decide according to your needs.x3 drive belt

When should a drive belt be replaced?

It should survive active duty for 50,000 to 100,000 miles without replacement.

It might be a good idea to have it replaced if you notice scratches, cracks, or frays on it. In addition, an abnormally sounding engine might also be a good reason to have it inspected. The final sign it being about to breathe its last is poor function of the components it links.

In any case, we advise you to replace it as scheduled. Failure to do so may result in greater expenses later on.

What are the 3 belts in a car?

You can find three types in your car: a timing, a serpentine, and V-belts.

The timing belt is located inside the engine itself, obscured from view. It features teeth on its surface, which fit into cogwheels. It synchronizes movable engine components while the car is running.

The serpentine belt winds around the engine, connecting its key components while delivering power. These components include the A/C, alternator, water pump, and power steering pump. When it breaks, the power supply to each of them is cut off.

The V-belts are now outmoded, though they once used to fulfill the task of the newer serpentine belt. They also provide power to the components mentioned above, but each is independent. It means that exactly one of them is assigned to each component. When one breaks, only its associated component’s function is jeopardized. They hold more tautly and are less prone to slipping. Given that they are usually found in older models, they can be harder to come by.

Should you replace the serpentine belt when replacing your alternator?

While it is not necessary for you to replace the serpentine belt when replacing the alternator, it is still a prudent choice to do so. It is because the belt is relatively cheap to kill two birds with one stone. The other option is to return to the shop later and replace it anyway. Getting an appointment scheduled may not always be easy. If you can, have both components replaced at the same time.

What happens to a car when the serpentine belt breaks?

Once it goes out of service, your engine will slowly stop working properly. Any key components inside it will soon lose their functions.

The power steering loss means turning your car will become an arduous task, perhaps even impossible.

Moreover, you will lose the soothing comfort of the AC. It leaves you at the mercy of the general temperature in your area.

The non-functional alternator leaves you with a slowly dying battery. Once it does indeed die, any components in your car which require electricity will cease to operate. Worst of all, you need at least some juice in your battery to turn on the ignition. Without it, you can’t start the car at all once you switch it off.

Without the water pump, your engine will start to overheat.

Driving your vehicle with a worn-out drive belt may lead to expensive damage. For this reason, we recommend that you have it replaced every 50,000 to 100,000 miles driven.

How do you know if your alternator belt is bad?

  1. Take your car out for a spin.

    A worn-out serpentine belt will often cause your vehicle to give out strange noises, so this is a good way to start the inspection.

  2. Listen to any whining or whirring.

    These high-pitched noises indicate your belt is about to break. They get louder the more you exert the engine, particularly when accelerating the car or ascending a steep slope.

  3. Notice if there is any squeaking going on under the hood.

    Again, it gets noisier the more pressure you put on the engine. If there is, your belt is likely slowly slipping from the components. While this may be remedied by simply reattaching it properly, it might be a good idea to have it replaced regardless. Better safe than sorry.

  4. Another noise associated with a bad alternator belt is knocking.

    This one is seldom as loud as the others and may take a trained ear to catch. You can usually hear this sound when the belt gets shaken up during rotation.

  5. Lastly, check whether you can hear a harsh grinding sound while you drive your vehicle.

    As with the previous ones, it gets louder as you accelerate.

  6. Whether you hear any of the peculiar sounds mentioned above or not, inspect the following visual cues.

    The absence of these sounds does not necessarily mean that all is well.

  7. While manning your vehicle, look closely at your interior lighting system.

    This system includes the dashboard, sun visor mirror lights, and overhead lights. If you notice they are not as bright as usual, your alternator belt might fail. However, ensure you inspect all of them as a whole. A single light not working properly does not mean your belt is busted. The alternator delivers power to all of them, so if you notice just one acting up, the root of the issue lies elsewhere.

  8. Inspect your dashboard and see whether an alternator or battery warning pops up.

    Many things can go wrong with either one of these components, and an old serpentine belt might be one of them.

  9. Check if the electronic components in your vehicle operate properly.

    Try rolling your windows up and down and see if it takes unusually long or if the movement is jagged. Power locks and adjustable seats may also act funny.

  10. If your belt is severely atrophied, it might produce a foul burnt smell.

    At this point, it has already damaged the alternator, so have your car checked immediately.

  11. Take a look at your battery’s power level.

    If it drops while you drive, the alternator is not charging it. While the alternator might be broken, your serpentine belt can also be the culprit.

  12. Notice if your car stalls while you drive.

    If these stalls are haphazard (you know you did not cause them), the alternator is probably lagging behind with its power delivery.

  13. The last signs to look out for are dim headlights.

    If you think the road in front of you is not as visible after dark as you are used to, your headlights are not bright enough. Either the issue lies in your bulbs, or the power delivered to them is insufficient. Driving with poorly functioning headlights is illegal in many countries, not to mention it is a danger to you and your passengers. Do not drive your vehicle if this is the case.

  14. Congratulations, you’ve reached the end of this guide.

    The less festive news is that if you noticed any of these signs, your alternator belt is likely due for replacement. Sorry to deliver the bad news!