Today we’re going to be talking about serpentine belts. Let’s start by talking about the accessories that are driven by the serpentine belt. First is the alternator. That’s the device that makes electricity to power the vehicle and recharge the battery. Then there’s the air conditioning compressor that makes cool air for you.

The power steering and power brake pumps are driven by the serpentine belt in most vehicles. Those pumps make the pressure that assists your steering and braking.

In many vehicles, the water pump is driven by the serpentine belt. The water pump is what circulates the coolant that protects your engine. In some cars, the water pump is driven by the timing belt.

The radiator cooling fans on some vehicles are also driven by the serpentine belt. Some have separate electric motors. That’s really a lot of work for one belt.

But modern engine design has a single belt that snakes around the front of the engine and drives most if not all of these accessories. Serpentine belts do a lot of work, but they’re tough and can last for thousands of miles.

Just how long will they last? That’ll vary for each individual car. Your manufacturer will have a recommendation for when it should be changed, but it could need it sooner. The good news is that a visual inspection can reveal a belt that’s getting close to failing.

Your service center can look at the belt: if it has more than three or four cracks per inch it needs to be replaced. A deep crack that’s more than half the depth of the belt – replace. Frayed, missing pieces, a shiny glazed look? It’s out of there.

What’s involved in replacing the belt? First the old belt is removed. Then a new one is fitted around all the pulleys for the accessories and the drive. There’s a special pulley called a tensioner.

This pulley is mounted to the engine block with a spring loaded arm. Its job is to apply the correct amount of tension to the belt to keep it from getting loose and maybe slipping off. Because the spring in the tensioner pulley wears out, AutoNetTV recommends replacing them at the same time as the belt. It just makes sense.

What are the warning signs that there’s a problem with the serpentine belt? You may hear a squealing sound from under the hood when accelerating. A loose belt might give you a slow, slapping sound.

What do you do if your belt breaks? If you’ve actually had that happen on the freeway, it can be a little scary. Often the first thing you notice is that you have no power steering or power brakes. Don’t panic – you can still steer and brake, but you’ll have to do the work. It’ll be harder to steer and you’ll need more time and effort to stop, so plan accordingly.

Your dashboard will light up will all kinds of warnings. You’ll see a warning about your cooling system if you have a water pump that’s driven by the serpentine belt. This is very critical because without your cooling system working, your engine will overheat. If you don’t stop you’ll have massive engine damage, maybe to the point that you need a new engine. Pull over as quickly as you safely can. Open your windows and turn the heater on full blast to provide a little engine cooling and pulled over as soon as possible.

The battery light will come on because the alternator isn’t working. If your car’s water pump isn’t driven by the serpentine belt, you’re not in danger of overheating so you can drive a little further if necessary. But the battery will run down to the point where the car won’t run and will just shut off. You don’t want that to happen while you’re driving.

Remember, this does not have to happen if you replace your serpentine belt on schedule. Ask your technician to check your belts and hoses from time to time so you can take care of them if they need to be replaced prematurely.

Don’t you hate it when you hear that squeal from under the hood? It usually means there is a problem with the serpentine belt.  The serpentine belt powers a lot of engine accessories. It runs the alternator-which charges the battery, the water pump-which cools the engine, the air conditioning and the power steering pump.  All pretty important parts. It is called a serpentine belt because it snakes around a bunch of engine components.

Serpentine belts are especially tough. They can last for years and go for tens of thousands of miles.  But, with time they wear out.  If your belt breaks while you are driving, everything will come to a halt within minutes.  You have to stop the car or it will overheat, potentially causing major engine damage. And it probably won’t be at a convenient time or place.  You might even need to get your car towed to a service center. That is why manufacturers recommend a belt replacement on schedule. You really should get it done on schedule because a belt failure will definitely take you off the road.

If you hear a squeal when accelerating or a slow, slapping sound at idle, you should have your serpentine belt looked at. Your service technician will visually inspect your belt to see if it needs to be changed sooner than scheduled.  If the belt has more than three or four cracks an inch, has deep cracks that penetrate half the depth of the belt, is frayed, is missing pieces or has a shiny glazed look, it needs to be replaced regardless of age or mileage.

Serpentine belt replacement is relatively inexpensive, especially compared with the cost and inconvenience of being stranded or getting a disabled vehicle to a service center for repairs.  An ounce of prevention is worth a pound of cure.