Car Parts Basic: the Serpentine Belt


Exactly how your car runs can be a mystery. Petrol goes in the tank, the engine fires, and off you go, right? Well, yes and no. One of the key components of your vehicle’s engine is the serpentine belt, which helps many of your car’s systems work, like the air conditioning and power steering. Auto maintenance and repair specialist The Humble Mechanic explains the important role your car’s serpentine plays and some common ways it may break down.

Hey everybody, it’s Charles from and today we are talking serpentine belts.

The serpentine belt is a vital component on most vehicles and it has the incredibly important task of driving engine accessories. The most common accessories driven by the serpentine belt are going to be the alternator, the power steering pump and the AC compressor. Some engines may also drive other accessories like the water pump. On most vehicles, a pulley on the end of the crankshaft is what turns the belt and drives the accessories. The system also consists of a tensioner to keep the belt tight and maybe even additional rollers to help guide the belt. These are commonly referred to as idler pulleys.

Maintenance intervals vary depending on the belt and the vehicle but typically range anywhere from 60 to 100,000 miles. It’s really important to perform periodic inspections on your serpentine belt.

Let’s start with a visual inspection. What you’ll be looking for is: cracks across the ribs of the belt; if the belt has a non-ribbed side; perhaps any glazing or really shiny spots; or any other signs of belt damage including the edges of the belt frame. Another way to inspect the belt is to use a serpentine belt rib tool. This is actually the best way to check for belt wear. As the belt wears into a pulley, the depth of the ribs become even deeper. This is a normal condition, but it may be really hard to see.

Using a tool like this, that can be purchased at most auto parts stores, is really the best way to inspect the belt. When you set this tool on the ribbed portion of the belt, it can show how much wear the belt has on it. Also, any oil or coolant saturation on the belt means it’s time to replace it and fix those leaks.

In addition to normal wear and tear, we also want to be aware of some types of failures. A complete failure of a serpentine belt is when the belt breaks or comes off the rollers. This means the accessories are not being driven and may result in no charging voltage, no AC or no power steering, and in certain cases can lead to vehicles overheating. We also may encounter some noise, like a squeak noise, when a serpentine belt’s worn out. Not only is it common when the belt wears but this can also be the sign of a failing tensioner or a failing bearing in any one of the pulleys.

When it comes to replacement of a serpentine belt, it’s usually pretty straightforward and requires very simple, basic hand tools. Most of the time, the biggest challenge is actually getting to the belt itself. When you’re doing the belt, draw out the pattern of the belt on a piece of paper or take a picture with your phone to help remind you of the routing of the belt.

If you guys have any serpentine belt questions or comments, feel free to leave them down below.

(Source: theAllstateBlog)

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