A typical car has two or three serpentine belts that drive various components, such as the power steering pump, air conditioner compressor, alternator and coolant pump. Serpentine belts don't last forever, though. Depending on the type of car you own and the way in which you drive it, your serpentine belts may last for 50,000 to 100,000 miles on average. But you can often tell when a serpentine belt has failed or is about to fail by looking for the following signs.
#1) Battery Won't Hold a Charge
If your battery keeps dying, it could be attributed to a bad serpentine belt. Assuming your car's alternator is driven by a serpentine belt -- and that belt fails -- the alternator won't be able to recharge your car's battery. The battery and the alternator are likely still good, but you need to replace the serpentine belt. Otherwise, the alternator won't recharge the battery while you drive.
#2) AC Not Working
Another possible sign of a failing serpentine belt is the air conditioner not working. Specifically, the air conditioner compressor is driven by a serpentine belt. Once the serpentine belt driving the air conditioner compressor fails, you'll no longer feel cold air coming out your car's air vents.
#3) Power Steering Not Working
Like the alternator and air conditioner compressor, the power steering pump is driven by a serpentine belt. And if this serpentine belt, your car will lose its power steering ability. Not only can this make it difficult to control your car; it makes turning dangerous, as you may fail to turn hard enough to stay in your lane.
#4) Squeaking Noise
You can often tell if a serpentine belt is bad simply by listening to your car when you first crank it. If the belt is worn, slipped, rotted or otherwise bad, it will likely squeak. The squeaking may only occur for 30 to 60 seconds immediately after starting your car,
#5) Overheating Engine
The worst symptom to experience when a failing serpentine belt is an overheating engine. While this doesn't apply for all cars, many cars use a serpentine belt-driven water pump to pump and circulate coolant through the engine. If the serpentine belt driving your car's water pump fails, you may notice your engine's temperature climbing dangerously high into the red zone.
While a failed or failing serpentine belt can cause a variety of problems, the good news is that it's a relatively inexpensive and easy part to replace.