All responsible vehicle owners understand that there’s going to be at least a little bit of routine maintenance necessary to keep their cars rolling down the road safely.
Most folks, though, anticipate that this routine maintenance is only going to involve airing up the tires every now and again, checking on the brakes, and replacing oil every 3000 to 5000 miles.
Unfortunately, that’s not all the maintenance that your vehicle is going to need.
Every 80,000 to 100,000 miles you’re going to have to do a more complete overhaul of your vehicle. At least with a few core components, anyway.
One of those core components is a serpentine belt.
What is the Serpentine Belt?
Back in the “old days”, every accessory in your engine bay had its own dedicated belt.
Your alternator had a belt. Your water pump had a separate belt. Your radiator fan had a belt. Your power steering system had a belt.
All of them had their own belts!
Nowadays, though, vehicles have what’s called a serpentine belt – a single belt that runs across a bunch of different pulleys throughout the engine bay to operate all of the different accessories at once.
The advantage here, of course, is that you have a single belt that needs to get repaired or replaced when something goes sideways under the hood. It’s a whole lot easier to pop one belt off and replace it than hunting down each individual belt, finding a way to access them, and replacing them separately.
The downside, though, is that there are a whole bunch of different things that can go wrong different spots on the serpentine belt to cause it to become compromised – or even start to shred it.
What Causes a Serpentine Belt to Shred?
Yes, you’re reading that right.
It’s possible for your serpentine belt to sustain so much damage that it begins to shred.
If that happens you are going to be in for a bit of a project, one that’s going to take a little more of your time (and probably a little more of your money) than you would have expected.
Let’s run through some of the most common root causes behind serpentine belt shredding.
Incorrect Alignment with Accessory Pulleys
One of the biggest culprits for a serpentine belt to begin shredding is that anyone of the accessory pulleys – your alternator, your water pump, your fan, your power steering, etc. – is just a little bit out of alignment.
If even one of those pulleys is only slightly out of alignment (and worse, if a couple of those pulleys are out of alignment) your belt is going to be pulled and tugged in the wrong direction.
That’s going to cause some serious damage, sometimes the point where the belt shreds completely!
This is the first thing you’re going to want to check!
Most of the time this happens when an accessory was repaired or replaced and the alignment wasn’t double checked before the serpentine belt got put back on.
Bad Idler or Tensioner Pully
If everything looks good to go and is aligned you may be dealing with an idler or tensioner pulley that isn’t behaving the way it should be.
These kinds of pulleys are used to alter the direction of the belt as it handles its responsibilities. If you have a bearing go bad on either one of these pulleys you’re going to start to see at least a little bit of tilting in one direction or the next.
That tilting – even just ever so slightly – is often enough to put extra pressure, extra attention, and extra friction onto your serpentine belt.
It’s not going to take very long until the belt itself begins to shred on you if that’s what’s going on.
Too Much Play in the Crankshaft
If you are dealing with a serpentine belt that has started to shred hopefully it’s because of one of the two problems that we highlighted above.
If not – and if you’re dealing with a serpentine belt that has begun to shred because of play in the crankshaft pulley – you’re probably looking at a significantly more frustrating and expensive repair.
Maybe you are dealing with a little bit of play in the harmonic balancer portion of the crankshaft. That’s still a troublesome fix, but it’s not as bad as actually having to play in the crankshaft itself.
This is the kind of trouble that needs to be diagnosed by a proper mechanic, though.
They’re going to be the ones that can let you know exactly what’s happening under the hood and they are usually going to be the ones that tackle this kind of repair.
Sure, if you’ve grown up with cars and are comfortable working on them you could probably take on this project in your driveway – if you have the tools and the time.
Most folks, though, are going to want to outsource this kind of heavy lifting to the professionals so that it gets done right and gets done much quicker.
How Do I Fix This Problem?
At the end of the day, if you are dealing with a serpentine belt that shreds on a regular basis – or a belt that has to be replaced multiple times in a short span of time – you’re going to want to visit a trustworthy mechanic.
Let them know what’s going on. Let them know what kind of work has been performed on the vehicle recently. Let them know when and how you notice your serpentine belt shredding.
They are going to want to poke around under the hood, inspect all of the different accessories that are connected to the serpentine belt, and then have a look at your crankshaft pulley and the crankshaft itself.
Give them plenty of time to make this diagnosis (though hopefully it’s pretty quick and easy to spot – like trouble with misalignment on your accessories or bad bearings).
They’ll point you in the right direction and will almost always be the folks to tackle fixing the problem if it’s more involved!