What Happens To A Car When The Serpentine Belt Breaks?

Often referred to as an alternator belt, fan belt, or accessory drive belt, the serpentine belt is designed to “spin,” or “drive” various mechanical components that are attached to the engine in your vehicle. These accessories are responsible for providing power to essential vehicle systems. Some of these systems include the car’s electrical, power steering, cooling, and even the A/C system. Essentially, the serpentine belt is responsible for turning all of them and keeping these systems running properly. If you compare cars, serpentine belts can vary by vehicle. But there are a number of symptoms to observe that can be signs of a failing belt.

Symptoms of a Failing Serpentine Belt

Generally speaking, the average serpentine belt lasts up to five years (or 50,000 miles) before it needs to be replaced. Many have been known to last for up to 80,000 miles without issue, but for an exact service interval, you should consult the owner's manual of your vehicle. Over time, the serpentine belt begins to fail due to the heat and friction it is subjected to every day when operating. Therefore, it must eventually be replaced in order to keep your vehicle running smoothly. If you believe your serpentine belt is beginning to fail, keep an eye out for the following symptoms:

1. Squealing Noise From The Front Of The Car

If you begin to notice a squealing noise emanating from the front of your vehicle, it could possibly be your serpentine belt. This sound could be caused by belt slippage or misalignment. The only way to ensure whether it’s your serpentine belt or not is to contact a professional mechanic and have them diagnose the issue and assess whether you need to replace the serpentine/drive belt.

2. Cracks or Wear on The Belt

You should physically inspect your serpentine belt on occasion to ensure it is in good shape. Check the belt for cracks, missing pieces or tears, abrasions, rib separation, uneven wear, and damaged ribs. If you observe any of these symptoms, you should replace your serpentine belt.

3. Air Conditioner or Power steering Are Not Working

When the serpentine belt completely fails and breaks off from the engine block, your car will break down. You may also notice a loss of power steering or air conditioning that stops working. If the power steering fails while the vehicle is in motion, it could create serious safety issues for both the driver and other pedestrians on the road. Preventative maintenance is the best way to ensure your belt does not break while you’re driving it.

4. Your Engine is Overheating

The serpentine belt helps provide the power needed to cool the car’s engine, so a failed belt can result in your engine overheating, due to the water pump’s inability to run from the broken belt. If your engine begins to start overheating, immediately have it inspected by a certified mechanic. Overheating can lead to a breakdown and cause permanent damage to your engine if left unaddressed.

What Happens if a Serpentine Belt Breaks?

Though your serpentine belt may not be prone to failing, it does wear down over time. As the belt begins to wear - or becomes damaged or contaminated - the engine accessories are not able to spin at the proper speed. For example, the engine’s alternator is designed to power the car’s electrical system and simultaneously recharge the battery during operation. When the alternator doesn’t spin fast enough, the output will diminish, which can lead to loss of vehicle power, dim headlights, loss of electronic functions, and sometimes a dead battery.

Most vehicle manufacturers recommend the inspection and replacement of the serpentine belt somewhere 60k and 90k miles. Some high-end serpentine belts have been designed to last more than 100k miles, due to advancements in material technology. But even a standard belt can survive for quite some time once it has become worn. However, driving with a worn belt brings substantial risk, because if the belt in your vehicle does break while you’re driving, the results can be startling at the very least - if not dangerous.

Many engine accessories are vital to your vehicle’s performance. So while it’s not necessarily a big deal if the serpentine belt breaks and your A/C stops working, it’s a much bigger issue if it causes your power steering or electrical system to fail.

Again, here are some of the primary consequences of a broken or worn serpentine belt:

  • A broken serpentine belt can lead to a sudden loss of power steering in your car, making your steering very difficult to turn. You don’t want this happening in the middle of a busy intersection when you’re trying to hang a right!
  • A broken serpentine belt causes the water pump to stop circulating coolant through the engine’s cooling system, causing it to overheat. This can happen at any time, if the belt decides to go out on you.
  • A broken serpentine belt also stops the car’s alternator from generating power, which is responsible for operating both the vehicle’s electrical and electronic systems. It also is responsible for recharge your battery, so if your headlights dim, the radio stops working, or your dash lights go out, your battery has probably died. And the reason may be that your alternator isn’t working because of a broken belt!

The serpentine belt should be kept in good working order, which includes servicing the tensioner and belt pulleys. Occasionally, the serpentine belt falls off and doesn’t break, simply because the tensioner and pulleys are worn, damaged, or misaligned. In this instance, replacing the belt will not be enough to solve the problem. The underlying issues that contributed to the damage or misalignment will need to be addressed before the vehicle will run properly. Serpentine belts can also fall off if they aren’t routed correctly, or if it is simply the wrong belt for the vehicle.

Vehicle owners should consider scheduling regular inspections and replacement of their serpentine belt as a part of their routine vehicle maintenance every 30k miles. While your belt will wear out over time, being proactive with preventative maintenance can help you avoid the dangers and potential hassle of a broken serpentine belt.