John’s Auto Care On Your Serpentine Belt



Today we’re going to be talking about serpentine belts for our Boulder, CO customers. Let’s start by talking about the accessories that are driven by the serpentine belt. First is the alternator. That’s the vital device that makes electricity to power the family car and recharge the battery. Then there’s the air conditioning compressor that makes cool air for you while you’re driving around CO in the summer.

The power steering and power brake pumps are driven by the serpentine belt in most Boulder auto owners’ vehicles. Those pumps provide critical pressure that assists your steering and braking.

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

The radiator cooling fans on some family cars are also driven by the serpentine belt. Some have separate electric motors. That’s really a lot of critical 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 essential work, but they’re tough and can last Boulder auto owners for thousands of miles.

Just how long will they last? That’ll vary for each individual car in the Boulder, CO area. Your auto maker will have a recommendation for when it should be changed, but it could need it sooner. The good news is that a visual inspection at John’s Auto Care can detect a belt that’s getting close to failing.

Your cheerful John’s Auto Care technician 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? Toss it.

What’s involved in replacing the belt at John’s Auto Care? 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 essential 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 and the automotive professionals at John’s Auto Care recommend Boulder drivers replace 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 around our Boulder streets. 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 a busy Eldorado Springs interstate, it can be a little scary. The first thing Boulder drivers usually notice is that they 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 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. Open your windows and turn the heater on full blast to provide a little engine cooling. Pull over as quickly as you safely can!

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 will just shut off. You don’t want that to happen while you’re driving in our local Boulder, CO traffic.

Remember, Boulder auto owners can avoid this stressful scenario if they replace their family car serpentine belt on schedule. Ask your cheerful John’s Auto Care service specialist to check your belts and hoses from time to time so you can take care of them if they need to be replaced prematurely.

John’s Auto Care
1900 55th St. #104
Boulder, CO 80301
303.442.2932

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John's Auto Care is an auto repair shop in Boulder, CO. Our mechanics treat every repair like it's our own car.

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