8 Major Signs Of Bad Timing Belt: Take Immediate Action!

The first sign of a bad timing belt is the check engine light will be on. Other common signs are frequent engine misfiring, rough idling, and excessive white smoke emission. Unusual ticking or knocking noises and engine overheating can happen due to a bad timing belt as well. If the timing belt is completely broken, the engine won’t even start. 

A timing belt can be bad for various reasons and signs of a bad timing belt can vary with those reasons. Keep reading and you will get a detailed explanation about bad timing belt signs. 

What Does A Bad Timing Belt Mean?

A bad timing belt means the timing belt is failing to properly synchronize the rotation of the camshaft and crankshaft. As a result, the engine inlet and outlet valves are not opening and closing at the proper times. 

A timing belt can be bad for several reasons. For example –

  1. The timing belt is torn, stretched, or worn out.
  2. The timing belt has slipped from the pulleys.
  3. The timing belt has oil or debris in it. 
  4. The timing belt tension is either too loose or too tight.
  5. The timing belt is completely broken. 

If the timing belt is facing any of these issues, you will notice several signs in your car. And, of course, you need to know when to change the timing belt before it’s too late. 

bad timing belt

8 Signs of A Bad Timing Belt and What Do They Mean?

When the timing belt of your car engine is bad, it will affect the engine timing. And consequently, your engine will show various symptoms. Here are the nine most usual indications of a bad timing belt. 

1. Check Engine Light On

Like all the other issues with your car engine, the check engine light will be on when the timing belt is bad (1). This sign might not be able to specifically warn you about the timing belt issue. But it will give you a headstart to look for other signs carefully. 

2. Engine Misfiring

Another common sign of a bad timing belt is the engine misfiring or suddenly losing power while driving. The camshaft is responsible for opening and closing the outlet and inlet valves to maintain the proper combustion process. 

When the timing belt is worn out or not tensioned properly, it can’t rotate the camshaft at the correct time. As a result, the valves don’t open and close at the right time, disrupting the combustion process. And so, your car faces frequent engine misfiring. 

3. Rough Idling

The average RPM should be between 600 to 1000 while your car is idling. The rate shouldn’t be fluctuating too much. 

In a rough idling situation, you will notice an abnormal fluctuation in the (RPM) tachometer. In this situation, the RPM might go below or above the idle RPM range frequently. This rapid fluctuation in the RPM meter is a sign of a bad timing belt. 

If your car is idling roughly, there will be abnormal bouncing and vibrating sensations in the car. 

When you idle the car with a bad timing belt, the frequent misfiring of the engine causes this rough idling. 

bad timing belt sound

4. Unusual Noise From The Engine

A bad timing belt sound can vary depending on the specific problem. 

When the timing belt is worn out or missing a tooth, it can’t rotate the camshaft properly and you will hear a ticking noise from the engine. 

If the belt is stretched or not tensioned properly, it causes tapping or knocking sounds by hitting the pulleys rapidly. 

The timing belt will make loud squeaking noises when it is exposed to oil and debris.

5. Engine Overheating

The ideal car engine temperature while operating is between 195 to 220 degrees Fahrenheit. If the timing belt is bad, it can cause your car’s engine to overheat. 

Due to a bad timing belt, the camshaft can’t open and close the inlet and exhaust valves in proper time. The delayed combustion process causes more pressure in the engine resulting in engine overheating. 

Moreover, the timing belt also operates the water pump. When the timing belt can’t rotate the water pump pulley efficiently, the pump can’t circulate the coolant throughout the engine. Coolant circulation is essential for keeping the engine within the specified temperature range. 

6. Excessive Emission

When the combustion process is delayed or hampered, it causes a lot of excess gas to trap within the cylinders. And this excess gas is pushed out through the exhaust pipe. 

So, when the timing belt is bad, you will notice too much white smoke coming out through the exhaust pipe. 

7. Poor Fuel Economy 

Due to interrupted combustion, the engine can’t burn the fuel efficiently. . As a result, fuel consumption increases. 

8. Car Difficult To Start

When the timing belt is severely torn, you will find it difficult to start the car due to reduced initial power transmission. 

But what happens when the timing belt breaks completely? If the timing belt is completely broken or slipped from the pulley, you won’t be able to start the car at all. And if this happens while driving, a car with a non-interference engine will stop immediately without any engine damage. 

On the other hand, a car with an interference engine can be exposed to severe damage. In this type of engine, there is no gap between the piston and valves. So, if the timing belt fails, the piston and valve will collide and damage the engine. 

When and How to Check The Timing Belt?

If you notice the signs of a bad timing belt mentioned above, you need to check the timing belt immediately. 

Moreover, many car manufacturers mention a specific interval for checking the timing belt, which is on average 30,000 miles of driving. Follow this interval for checking the belt. And, check this out if you’d like to know about the differences between driving belts and timing belts.

Can I Check A Timing Belt Myself?

It’s recommended to take help from a technician for checking the timing belt. Especially to identify if the belt is tensioned correctly or not. However, if you have prior experience changing the timing belt, you can check the timing belt yourself. 

Here’s what you need to check –

  • Check if there is any oil leaking from the timing belt cover. It may not directly relate to a bad timing belt, but it can cause the timing to be off and damage the timing belt. 
  • Open the timing belt cover with a compatible wrench and visibly inspect for any signs of damage in the timing belt including cracks, missing teeth, or fraying. 
  • Check if there is any oil, debris, or foreign object stuck in the belt. 
  • Measure the tension of the timing belt. The following video will help you with that. 
  • Inspect the relative components like the pulleys and the water pump. If you find any damaged components, fix them as soon as possible. 
Can I Check A Timing Belt Myself Infographic

If the timing belt is not properly tensioned, adjust the tension and align the belt properly. However, if the belt is damaged, you must replace it immediately. A damaged timing is destructive for your car’s engine. 

Tips to Make Timing Belt Last Longer

Here are some tips that will make your engine’s timing belt last longer. 

  1. Keep the timing belt properly tensioned. If the timing belt is tensioned too tight or too loose, it can get damaged quickly. 
  2. While checking the engine for maintenance, usually twice a year, check the timing belt as well. If it has oil or debris in it, clean them. 
  3. If you notice any oil leak from the timing cover, immediately check the valve cover and sealants for oil leaks, and replace the broken or worn-out valve sealants. 
  4. Make sure the engine doesn’t overheat. An engine can overheat for many reasons, identify what caused the problem and fix it immediately (2).
  5. Replace the timing belt after the manufacturer’s recommended interval even if the timing belt looks good.

Is It Safe To Drive A Car With A Bad Timing Belt?

No, it is not safe to drive a car when the timing belt is bad. If the timing belt fails, the whole car engine function will be hampered. And it’s risky to drive a car when the engine performs poorly. 

Moreover, as mentioned earlier, in some cases, a bad timing belt can even damage the car’s engine badly. Speaking of timing belts and car engines, here you’ll get to know everything about timing belts on Honda Odyssey.

Getting back to the point, you should not even consider how long can you drive with a bad timing belt. If you see the sign of a bad timing belt, you need to check and if required, replace it right away.


Can A Timing Belt Last 300,000 Miles?

It is possible for a timing belt to last 300,000 miles. But it’s not very common. Timing belts are typically designed to last for about 60,000 miles to 100,000 miles of driving. Some high-quality timing belts may be able to last longer like 120,000 miles of driving. However, you should not use a timing belt for 300,000 miles. 

How Much Does It Cost To Fix A Timing Belt?

A timing belt costs around $100 to $500, depending on the quality. And the replacement cost will be an additional $300 to $500, depending on your region. So, in total, you may need to spend $400 to $1000 to fix a timing belt. 

What Causes A Timing Belt To Mess Up?

Improper timing belt tension and misalignment cause the timing belt to mess up. Driving the car harshly for a long time and not changing the timing belt after the recommended interval can mess up the belt as well. Debris or oil on the timing belt can mess it up too. 


These are the signs of bad timing belt. If you notice these signs, you need to inspect the timing belt and may have to change it. 

The timing belt is often neglected but is an essential component of the engine. So, take proper care of it and your engine will perform better for a long time. 

That’s it for today. Goodbye!

Written By

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Aaron Byrne

Hi, Aaron Byrne here. I'm an expert automotive mechanic with 10 years of experience. I work on engine parts especially timing belts for their repair, maintenance, and replacement.

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at Autoglobes.com with a passion for the automotive industry.