What Happens When a Timing Belt Breaks While Driving?

When the timing belt breaks while driving, you will hear loud noises, the engine may stop running, and it may suffer severe internal damage. Moreover, other possible engine damages include bent or broken valves, damaged cylinder head or wall, damaged camshaft, and a damaged piston.

Imagine you’re driving down the highway, and suddenly, your vehicle sounds like it just exploded. You pull to the side of the road and notice there is no smoke coming from the engine. But when you look under the hood, you see the timing belt has broken.

So, today I will discuss what happens when a timing belt breaks while driving.

Now, let’s dive into the detailed discussion of the scenario, the symptoms, the major causes, and their possible solutions. 

Can a Timing Belt Break While Driving?

Yes, the engine timing belt can break while driving without any prior warnings. Timing belts wear out and sometimes break when they are under excessive load. When your timing belt wears out, your engine will not run as smoothly as expected.

The timing belt may also break due to low or excessive high tension, incorrect tension adjustment, a ruptured cord line, a water pump seizure, and many other reasons. The symptoms of a bad timing belt include weird ticking noises, engine misfiring, and rough idling. 

Summary:

Timing belts can break while driving without any prior warning. The symptoms of a bad timing belt include weird ticking noises, engine misfiring, and rough idling. In case of a broken belt, the engine will face further damage or stop working.

What Happens When a Timing Belt Breaks While Driving?

When a timing belt breaks, the engine will stop working, and it can cause further damage to your engine. Also, you can no longer drive your vehicle with a broken belt. So you must replace it as soon as possible to avoid serious consequences. 

The timing belt is a major component of the timing system of an engine. This system consists of the belt, tensioner pulley, camshaft pulley, and crankshaft pulley. The belt connects all three pulleys together and allows them to synchronize their movement.

If the belt breaks and some of the components fall out of sync, it can damage the rest of the engine components. For example, if one of the valves doesn’t close quickly enough, it might hit the piston and substantially damage the piston and the valve.

However, it is important to note that what happens to the engine when the timing belt breaks depends on the engine type. Depending on the valve and piston interference, the engines are categorized into two main types.

• Interference Engine
• Non-interference Engine.

Summary:

When a timing belt breaks, the engine will stop working and can cause further damage to the engine. You can no longer drive your vehicle with a broken belt, so you must replace it as soon as possible to avoid serious consequences.

How Do I Know If My Engine Is an Interference Or Non-Interference?

In simple words, an interference engine has no gap between the pistons and the valves. On the other hand, a non-interference engine has a gap between the pistons and the valves. Due to this, when a timing belt breaks, it affects both engines differently.

What Happens If a Timing Belt Breaks On an Interference Engine?

In interference engines, pistons can move due to inertia even after losing the synchronization. And, since there is no gap between pistons and valves, it can cause further damage to the engine. Pistons and valves, for example, can bend or break.

What Happens If a Timing Belt Breaks On a non-Interference Engine?

Comparatively, on non-interference engines, the engine automatically stops itself when the timing belt breaks. Since there’s a gap between the pistons and the valves, it prevents further damage to the engine when it is out of synchronization.

What are The Symptoms Of A Broken Or Cracked Timing Belt?

You already know when the timing belt breaks, the crankshaft, camshaft, and other components lose their synchronization. Additionally, here are some common symptoms and potential consequences of a bad timing belt.

Ticking Noises

The most common symptom of a timing belt failure is when you hear weird ticking noises from the engine compartment. Although low oil pressure can be the reason for the noise, if the oil level is ideal, the timing belt has failed.

Engine Light Flashing

The second symptom is when you see the engine light is on and flashing, which means there’s something wrong with the engine. Ideally, the P0017 is the engine fault code related to the timing belt, crankshaft, and camshaft correlation error.

Blown Engine 

If your engine is an interference engine, it’s prone to severe damage when the timing belt breaks. The piston may damage and bend the valve, damaging other crucial components of the engine. If you hear a crackling noise, stop the engine immediately.

The Engine Won’t Start/Misfire

The engine may misfire if the timing belt is broken or not functioning properly. Also, you may not be able to start the engine entirely if that happens. You may hear the clicking sound of the starter motor when you attempt to start the car, but the engine won’t start.

Summary:

When a timing belt breaks, it affects both engines differently, depending on whether the engine is an interference or non-interference engine. 

What Causes Timing Belt To Break?

The timing belt can wear out and break for any reason without any prior warning. There are six possible causes behind the timing belt failure. Here’s the list.

Reason 1: Excessive Load

Excessive load on the timing belt is a major cause of timing belt failure. The belt might have worn-out teeth, incorrect tension adjustments, or rough pulleys. As a result, it creates more friction and excessive load on the timing belt, causing it to fail.

Change the belt if it has worn-out teeth and adjust the correct tension to the belt. If the belt has incorrect tension, you need to adjust it for optimal performance. There are two major ways of adjusting a timing belt: The plunger method and the sonic tension meter.

Consider watching this video to adjust the timing belt tension correctly.

It may sound interesting and weird at the same time, but did you know you can adjust the timing belt tension with your smartphone? There are apps to measure the belt tension with your smartphone, or you can even use a good guitar tuner app.

Here’s the comparison video of checking and adjusting the belt tension using smartphones and other factory tension adjustment tools. 

Reason 2: Misalignment

Proper belt tension and pulley alignment are essential for maximizing your timing belt’s potential. Misalignment can prematurely wear the pulley flange or cause frayed edges. 

This can result in reduced load transmission, system efficiency losses, or even a complete run-off of the pulley.

There are two main belt and pulley misalignment types: Angular misalignment and Parallel misalignment. Check the below picture for a visual understanding.

Image Source: JE Bearing

Consider watching this video to understand these two types of misalignment better. 

You can diagnose the timing belt for misalignment with some easy procedures. Generally, the timing belt misalignment causes weird noises in the engine chamber while running. There are primarily three methods: with bare eyes, traditional method, and laser.

Alternatively, you can use the water spray method. Here’s the complete guide on how to use the water spray test for pulley misalignments. 

Reason 3: High/low Tension

Excessive high or too much low tension in the belt is another reason the timing belt can fail. Low tension in the belt causes the belt’s teeth to shear and wear. It also causes a lack of proper grip between the pulleys and the timing belt, resulting in slippage.

Excess tension can also cause the timing belt to wear off from friction and heat. High tension can also cause misalignment due to excess pressure between the belt and pulleys. When the timing belt slips, it causes squealing noises, excessive friction, engine overheating, and misfiring.

Reason 4: Oil Leakage

Another reason for a timing belt failure is oil leakage. Oil leakage in the engine compartment can reach between the belt and the pulleys, causing the belt to slip. Furthermore, it disrupts the proper grip and friction between the belt and pulleys.

Due to oil leakage, debris and dirt can clog the belt over time. So, if you find out there’s an oil leak, fix the leak immediately and clean the belt from debris.

Reason 5: Water Leakage 

In a similar way to oil leakage, water leakage can interfere with the timing belt’s performance. Water leakage can contaminate the timing belt causing it to dampen and lose friction. The effect can worsen if the leaking water is mixed with antifreeze.

Reason 6: Damaged or Worn Out Pulleys

Pulleys are the major components where the timing belt runs. If the pulleys are worn out, the timing belt can slip and can overheat due to generating excess friction. Additionally, the timing belt will fail to maintain proper tension with worn-out pulleys.

Summary:

Timing belts can break due to excessive load, misalignment, excessively high or too much-low tension, water/oil leak, and damaged or worn-out pulleys.

Can You Drive With a Broken Timing Belt?

No, you cannot drive with a broken timing belt. If the timing belt is broken, you won’t even be able to start the car since the engine won’t work without it. Tow the car to the nearest service center in this condition; do not attempt to start the engine.

How Long Can You Drive With A Bad Timing Belt?

It’s not recommended to drive a car with a bad belt in the first place And, there is no doubt that you cannot drive a car with a broken timing belt. The belt can snap at any moment, so don’t take the risk if it is damaged but not yet broken.

Sometimes, people get confused between a timing belt and a chain. If you ride a Mazda, this guide will help you become aware of whether the car has a timing belt or a chain.

Summary:

You cannot drive a car with a broken timing belt. Tow the car to the nearest service center if the timing belt is broken, and don’t attempt to start the engine.

How to Replace a Timing Belt?

You can replace a broken or damaged timing belt yourself if you don’t want to spend on a mechanic. The process is easy but needs a lot of patience. Typically, the timing belt changing procedure can take around 4-8 hours, depending on the type of vehicle.

Here’s a quick overview of how to replace the timing belt in easy steps.

Tools Needed

• New timing belt. (according to your vehicle)
• Jack and Jack stand.
• Combination wrench.
• Socket wrench.
• Torque wrench.
• Screwdrivers.

Step 1: Prepare the Vehicle

Disconnect the negative cable from the battery and jack up the front part of your car for easier access to the engine compartments. Also, engage the car’s handbrake to prevent accidental movement or spinning of the vehicle.

Step 2: Remove the Fan Belt and Power Steering Belt 

To access and remove the timing belt, remove the fan and power steering belt. Loosen the alternator motor by gently unscrewing the bolt and nuts holding it to remove the belt. Similarly, loosen the power steering belt and crankshaft pulley.

Step 3: Remove the Belt Case

In the next step, you have to remove the timing case that covers the timing belt. In some vehicle models, you will get clear access to the timing belt after removing the timing case. Some vehicle models, however, require you to remove other engine components like the water pump, radiator fan/cap/plug, and intake hoser to access the timing belt.

Step 4: Remove the Broken Belt

Follow the manufacturer’s instructions when loosening the timing belt tensioner. Once you loosen the tensioner cog, the belt will lose tension, and you can remove it. Make sure to remove the timing belt gently without triggering the tensioner cog.

Step 5: Replace the Timing Belt

Install the new timing belt and assemble the engine’s other components accordingly. Make sure to avoid some common mistakes while installing the belt if you don’t want to regret it later.

Tighten the tension, and follow the manufacturer’s guidelines to adjust the timing belt tension for optimal performance. Finally, reconnect the negative battery cable.

Here’s the complete walkthrough video on how to replace the timing belt. Consider watching it if the above replacement steps seem confusing.

Precautions

• Make sure you replace the timing belt when the engine is cold. If you have recently driven the car, wait at least 3-4 hours. 
• Make sure there’s no angular or parallel misalignment.

Summary:

To replace a timing belt, first prepare the vehicle and remove the fan belt and power steering belt. Then disassemble the belt case to remove the broken belt. Finally, install the new timing and belt and tighten the tension along with the screws. 

How Much Does It Cost to Replace a Timing Belt?

Typically, the timing belt replacement can cost between $300-$500 for average-size cars. The replacement would cost more for larger cars, SUVs, and trucks since they have bigger engines. Additionally, the labor cost can range between $245-$450. 

FAQs

Last Words

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