Due to the nature of the drivebelt (sometimes called a "serpentine" belt), in that it's a relatively simple micro-V grooved strip of reinforced rubber, the only three problems you're likely to face are the belt slipping, separation of the ribs on the grooved side of the belt, or the belt snapping!
In the event of a slipping belt you may find the components it's powering struggling to work, such as intermittent power steering, flickering lights etc, and you'll pretty much always hear the belt squealing particularly when you first start the car from cold.
The embarrassingly loud nose will increasing in pitch as the revs rise. If your belt starts screeching don't ignore it. It may just need the tension adjusted or it may need to be replaced.
As the belt is pretty much always visible within the engine bay (and possibly also through the wheelwell) keep an eye on its condition – even very worn looking belts can work without apparent issue – but a damaged or worn belt should be replaced immediately – complete failure causes critical loss of all the devices the belt powers – so reduced power steering assist, insufficient coolant being pumped through the engine, and no charge going to the battery!
A worn belt, misaligned pulleys, debris in the V grooves, belt tension, or faulty components are just some of the common problems you can encounter. To determine the failure, spray a small amount of water onto the belt surface while the engine is running.
A worn belt generally will quiet down once it’s sprayed, but a misaligned belt due to a pulley will continue to chirp or even chirp louder.
A belt that has suffered separation of the plies and has lost some of its ribbing can emulate the sound of a serious internal engine problem, such as a connecting rod knock.
This is caused by the belt's automatic tensioner cycling rapidly back and forth. It is a relief indeed when such a serious-sounding problem turns out to be nothing more than a faulty drivebelt!
Tools you need to replace your drivebelt
Many belts can be replaced with a basic tool kit. Removal is a matter of releasing the tension applied to the belt (often via the tensioner, sometimes via the alternator mounted on a swinging bracket) and sliding the belt off the pulleys.
However, cars with automatic tensioners may need a special tool to release the tension, as many of these applications have extremely limited clearance between the driven components and the vehicle's unibody structure.
There are several different tools depending on the vehicle. They are commonly a long thin bar with some kind of socket that connects to the tensioner.
Tuning the bar releases the tension allowing you to remove, then replace the belt. Due to many belts having limited access, even if you only need to loosen one nut you may need to invest in a long handled wrench, which will not only give you access, but will also increase the leverage you apply to the tensioner.
How to extend the life of your drivebelt
As with all serviceable parts on a car, you should be prepared to replace the belt at the scheduled service interval, or whenever there is an issue with it.
Keep the engine bay clean but don't be tempted to apply any lubricant to the belt, which can cause it to slip.
How long should a drivebelt last?
How long is should last depends on the use the car gets, and the recommended service intervals. It's not unusual to get 50,000 miles from a belt, but at the same time don't be surprised if yours lasts a lot less time – particularly if it becomes contaminated with oil or similar.
You should check the belt regularly for signs of wear, damage, or cracking and change it at the first sign of degradation. A very shiny belt is also a sign replacement is potentially overdue.
How much does it cost to replace a drivebelt yourself?
In general the cost of the actual belt isn't too great – usually around $20. If a special tool is required to facilitate the loosening of the tensioner, then you must also factor that cost in.
Expect to pay up to $30 for the correct tool if yours can't be removed with a regular tool kit.