Learn about the different belts in your vehicle, including what they do, how you can maintain them, and what can happen when a failure occurs.
Belts serve an important function under the hood of your car, transmitting engine power to critical systems throughout the vehicle. When one wears out or fails, it can cause an annoying breakdown – or worse, severe engine damage.
Sometimes, the failure relates to the most understood component -- the serpentine belt. However, depending on the age of your vehicle and the design of your engine, there could be multiple belts powering different accessories. That means, a proper response to any failure is necessary, since these myriad belts are critical to the efficient operation of the entire propulsion complex.
What Belts Are Typically Found In A Vehicle?
To begin, let’s investigate the wonderful world of beltdom. Bear in mind that while the list typically applies to everything in this component universe, some belts may or may not be in your vehicle, depending on the design of your individual powerplant.
Serpentine Belt
Long and thin, a serpentine belt curves around pulleys like a snake (hence its name). It is the main belt in a vehicle, and it powers most of the engine accessories, such as the alternator, water pump, air conditioning compressor, and power steering pump. If this belt fails, the engine may overheat, the battery may not charge, the air conditioning may not work, and the power steering may become difficult to operate.
*Note that the Serpentine Belt is sometimes referred to as the Drive Belt or occasionally, a Multi-Rib Belt.
Timing Belt
This belt is responsible for rotating the camshaft in an internal combustion engine (ICE). If the timing belt fails, the engine may stop running entirely or the engine’s valves may collide with the pistons, causing severe engine damage.
*Note that the Timing Belt can also be referred as the Timing Chain, Cam Belt or the Toothed Belt.
V-Belt
Named for their deep “V” shape, V-belts were the standard before serpentine belts. Older engines used multiple V-belts coming off the crankshaft to power various accessories, such as the alternator, water pump, A/C compressor, and power steering pump.
Ultimately, serpentine belts replaced V-belts, as they are considered easier to maintain and replace.
*Note that V-belts are sometimes referred to by the individual accessory group they power, such as a Fan Belt or Alternator Belt. They are also sometimes more simply called Accessory Belts.
Best Practices For Belt Maintenance
There are a number of elements relating to a solid belt maintenance program.
These may be seemingly “simple” car parts, but regular investigation of their condition and performance not only helps extend their life, but also helps prevent problems from occurring in the first place. Failure to do so can create direct damage to belt components, such as cracking and splitting. Sometimes, a belt can take on a “glazed” appearance, which happens when it wears down from excessive heat or from slipping on the pulleys.
Here are some suggested best practices associated with a regular belt maintenance program.
Inspection
Check belts regularly for signs of wear, cracks, abrasions, or fraying. This process should be done at least once a year -- or more frequently, if you’ve seen problems in the past.
Tension
Ensure that belts are properly tensioned. Loose belts can cause premature wear, while at the same time belts that are too tight can cause component stress on critical elements such as pulleys, bushings and bearings.
Alignment
Make sure that belts are properly aligned with each pulley. Misalignment can cause excessive wear and, in some cases, early belt failure.
Replacement
Belts should be replaced at manufacturers’ recommended intervals or sooner if they show signs of wear. For example, most serpentine belts should be replaced every 50,000 to 70,000 miles, while timing belts should be replaced every 60,000 to 100,000 miles. Of course, each engine is different and should be based on how the vehicle’s engine is utilized.
Environmental Factors
Belts are prone to excessive climatic heat, cold, moisture, chemicals or damage from clag, mud or grit. Any of those processes can cause early belt deterioration. To avoid this, it's important to keep the engine bay clean and free of leaves, dirt, oil and/or any chemical overspray, while at the same time periodically conditioning the belts with a protective spray or similar viscous solution.
Routine Maintenance
Regular routine maintenance, such as oil changes and tune-ups, can also help extend the life of belts. This is because proper maintenance can help to keep the engine running smoothly, thus reducing stress on the belts.
Belt Failure Symptoms
Nearly everyone has experienced belt failure, but just in case you haven’t, here are some common symptoms that will alert you it may be time for a belt replacement.
Squeaking or Squealing
One of the most common symptoms of a failing belt is a squealing noise coming from the engine bay. This is particularly true when the engine is first started or when the accelerator is pressed. The noise is usually associated with a loose or worn belt slipping across the face of a related pulley.
Alternator Warning Light
If the serpentine belt fails, it may cause the alternator to stop working which, in turn can result in a warning light on the dashboard.
Engine Overheating
If the belt that drives the water pump fails, it can cause the engine to overheat since coolant will not be circulating properly.
Dead Battery
If the serpentine belt fails, the battery may not charge. This may cause it to go flat, leading to starting problems.
Power Steering Failure
If the belt that drives the power steering pump fails, the power steering system may fail making it difficult to operate the vehicle’s steering system.
Engine Misfire
If the timing belt fails, the condition can cause the engine to misfire, or even stop running entirely. A malformed or broken timing belt can also create valve/piston collisions leading to severe engine damage.
Air Conditioning Failure
If the belt that drives the air conditioning compressor fails, the air conditioning system may fail.
Engine Thumping or Knocking
If the belt tensioner, idler pulley, or other belt-related components fail, these noises can announce the onset of an engine failure.
Insights Into Belt Removal & Replacement
Depending on the individual belt and how it relates to associated mechanical components, belt removal and replacement should be executed with a degree of caution. Frankly put: some DIY processes are just easier than others.
Here are some tips relating to the level of ease when dealing with each belt, and why this information is important to you.
Serpentine Belt
Replacing a serpentine belt is a relatively straightforward task that can be performed by a DIYer with basic mechanical skills. This belt is located at the front of the typical engine and can be accessed easily, making it a good choice for a beginner to tackle.
However, when you’re looking at a transverse engine (i.e., sideways in the engine bay) depending on how much space the particular engine takes up, this may not be worth the time/cost to do it yourself.
Timing Belt
Replacing a timing belt is a complex task that requires a high degree of mechanical knowledge and experience. The timing belt or timing chain is located at the front of the engine behind the timing cover. Consequently, replacing this component requires the removal of a myriad of affiliate components.
For these reasons, it's generally recommended that timing belt replacement be performed by a qualified professional offering a complete engine shop capability.
V-Belts / Accessory Belts
Replacing accessory V-belts can vary in difficulty depending on the make and model of the vehicle. In some cases, the belt may be located in a difficult-to-reach area, while in other vehicles it may be more accessible. That said, as a general rule, drive belt replacement is usually straightforward and can be performed by a DIYer with basic mechanical skills.
So, there you go; a lot of useful information you can leverage when considering engine belts. Just remember, every engine vehicle is different depending on the brand, year, model and configuration. So, if you want to ensure that you understand your vehicle specifically, always consult your Owner’s Manual first.