Automotive Maintenance: How to Tell If Your Car’s Belts Need Replacing
Belts are a key maintenance item in any car. These simple components look like oversized rubber bands, and can range in size from about a foot to six feet or more. They’re found on all cars, and are used to transfer power from the engine to other rotating devices needed for the car to function.
Included among the devices that may use belts to drive them are the power-steering pump, alternator, air-conditioning compressor, and water pump. Most cars newer than the 1980s drive several of these accessories off of one long belt, called a serpentine belt, instead of separate smaller belts.
No matter what the particular configuration your car uses to drive its various systems, belts are critical components. Without them, your vehicle won’t go very far. And like most consumable parts, belts wear out and need replacement from time to time.
Here are some simple ways to tell if your car’s belts need attention:
One of the surest indications that a belt needs replacing is how it looks. Over time, belts get hard from the heat, flexing, and general stresses of operation. This can cause cracking. In more extreme cases, chunks can come out of the belt. If you see either of these signs on a belt it should be replaced as soon as possible, even if you haven’t observed any of the other symptoms described in this article.
In some cases — for engine timing belts in particular — the belt can’t easily be inspected visually. And timing belts don’t really give off any signs that they’re about to fail. Worst of all, when the timing belt breaks, it typically causes expensive internal damage to the engine. For this reason, the only practical way to judge when it’s time to replace the timing belt is by how many miles the car has on it. In most cases, engine-timing belts should be replaced at about 100,000 miles. But every automaker has its own specific mileage they recommend to replace this belt. To find out exactly when yours should be replaced, check your owner’s manual or discuss the matter with a qualified mechanic.
Squealing, chattering, or chirping
If you’re hearing shrill, high-pitched noises from under the hood, it’s possible that you have a problem with one or more of your belts. These sounds are simply the noise being made when the belt slips on the pulley. It generally indicates a loose belt, whether from stretching, improper adjustment, or broken components.
If a belt is slipping, or rubbing on other components, the friction will cause it to heat up. This creates a burning-rubber smell. In extreme cases, the belt can heat up to the point where it’s giving off grayish-blue colored smoke.
Most cars built before approximately 2006 have hydraulically boosted power steering. In this type of system, a belt transfers power to a pump, which sends pressurized fluid to the steering system to amplify the driver’s efforts and make the steering wheel easier to turn. If the belt is slipping, the pump won’t provide as much pressure and the steering wheel will become more difficult to move. This is often accompanied by the squealing noise described earlier.
The pump that circulates water through the engine to cool it is driven by a belt. As with other belt-driven systems, if the belt is slipping or has become disconnected, it will compromise the system. In this case, if the water pump isn’t turning as fast as it should, the engine can overheat.
Electrical and battery issues
A belt running off the engine turns the alternator, which generates power to charge the battery. If the belt that drives the alternator is in bad condition, it can slip, reducing how much power the alternator will generate. This can cause dim headlights, trigger a warning light on the gauge panel, or cause the battery to weaken or die.