A failing timing belt represents one of the most catastrophic risks to your engine, capable of causing thousands of dollars in damage within seconds of complete failure.
This critical rubber belt synchronizes your engine’s valves and pistons, ensuring they work together in perfect harmony. When it fails, the results can be devastating and expensive.
The most common symptoms of a bad timing belt include ticking or clicking noises from the engine, engine misfires and rough idle, oil leaks near the timing cover, excessive exhaust smoke, engine failing to start, loss of power during acceleration, and check engine light activation.
Timing belt replacement typically costs between $500 and $1,500, depending on your vehicle and whether additional components like the water pump are replaced simultaneously.
Understanding these warning signs and replacing your timing belt preventively can save you from complete engine destruction. This guide covers the seven key symptoms, replacement costs, and critical maintenance intervals to protect your engine investment.
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.
How a Timing Belt Works?
Unless you drive an EV, all modern vehicles have either timing belt or timing chain. For more info about timing chains.
A timing belt is responsible for synchronizing the rotation of the crankshaft and camshaft(s).
This precise timing makes sure that the engine’s valves open and close at the correct intervals relative to the position of the pistons, allowing for proper intake of air and fuel, and exhaust of combustion gases.
The belt is typically made of reinforced rubber with teeth that mesh with sprockets on the crankshaft and camshaft.
As the crankshaft rotates, driven by the power of combustion, it turns the timing belt, which in turn rotates the camshaft(s) at exactly half the speed of the crankshaft.
Engines are classified as either interference or non-interference types, and an engine’s type has a major effect on timing belt failure:
- In interference engines, the pistons and valves occupy the same space in the cylinder at different times. If the timing belt breaks, the piston can collide with open valves, which can cause severe (and expensive) engine damage.
- Non-interference engines have adequate clearance between pistons and valves, even if the timing is off. While a broken timing belt will still cause the engine to stop running, it’s less likely to result in catastrophic damage.
Timing Belt Location
Your car’s timing belt is found inside the timing cover. The belt is located near the front of the engine and is constructed from rubber. If you notice a heavy-duty metal construction instead, your car uses a timing chain.
The timing belt is an essential component for normal engine operation. The car engine cannot run properly without a reliable timing belt.
Symptoms of a Bad Timing Belt
A few timing belt warning signs indicate you have a worn-out or broken timing belt, which will require you to replace or contact a professional mechanic to replace it and diagnose other internal components.
#1. Ticking or Clicking Noises from Engine.
A failing timing belt often produces distinctive ticking, clicking, or rattling noises coming from the front of the engine, particularly around the timing belt cover area.
These sounds occur when the belt’s teeth begin to wear, slip, or when related components like tensioners and idler pulleys start to fail.
The ticking sound typically becomes more noticeable during idle and may increase with engine RPM.
Unlike valve train noises that come from the top of the engine, timing belt-related sounds originate from the front and may be accompanied by a rhythmic pattern that matches engine speed.
Worn timing belt teeth can cause the belt to slip slightly on the pulleys, creating intermittent clicking sounds as the teeth attempt to maintain proper engagement.
This slippage also affects engine timing, potentially causing performance issues that accompany the audible warnings.
Pay particular attention to any new noises from the front of your engine, especially if they’re accompanied by other symptoms.
Timing belt tensioners and idler pulleys can also fail, creating similar sounds that indicate immediate timing belt service is needed to prevent complete failure.
Never ignore unusual noises from the timing belt area, as they often provide the only advance warning before catastrophic belt failure. Have any front-engine noises diagnosed immediately to determine if timing belt replacement is necessary.
#2. Engine Misfires and Rough Idle.
When a timing belt begins to stretch or slip, it affects the precise timing between pistons and valves, causing engine misfires, rough idle, and overall poor performance.
You’ll notice the engine running unevenly, particularly at idle, with possible shaking or vibration throughout the vehicle.
Timing belt stretch allows the camshaft timing to become retarded relative to the crankshaft, meaning valves open and close slightly later than optimal.
This timing disruption affects combustion efficiency, causing incomplete fuel burning and resulting misfires that you’ll feel as engine roughness.
The misfires may be more noticeable under certain conditions, such as during acceleration or when the engine is under load.
You might experience hesitation during acceleration, reduced power output, or a general feeling that the engine isn’t running as smoothly as normal.
Modern engines with sophisticated computer controls may detect timing inconsistencies and trigger diagnostic codes related to camshaft or crankshaft position sensors. These codes often indicate timing issues that can stem from timing belt problems.
Address engine misfires promptly, especially if they develop suddenly or worsen over time. While other issues can cause misfires, timing belt problems require immediate attention to prevent complete engine failure.
#3. Oil Leaks Near Timing Cover.
Oil leaks around the timing belt cover area often indicate problems with timing belt components or related seals that require immediate attention. These leaks can accelerate timing belt deterioration and may signal that major timing belt service is overdue.
The timing belt cover protects the belt from contamination, but oil leaks can occur from several sources including the front crankshaft seal, camshaft seals, or gaskets between the timing cover and engine block.
Oil contamination severely shortens timing belt life and can cause sudden belt failure. Look for oil accumulation around the timing cover, particularly near the bottom where gravity causes oil to collect.
Fresh oil leaks appear wet and may drip onto the ground, while older leaks create dark, sticky deposits that attract dirt and debris.
Oil leaks onto the timing belt itself create extremely dangerous conditions, as oil causes the rubber to deteriorate rapidly and can make the belt slip on its pulleys. This slippage affects engine timing and significantly increases the risk of complete belt failure.
Address timing cover oil leaks immediately, as they indicate both immediate timing belt contamination risk and the need for seal replacement that’s best performed during timing belt service. Continuing to drive with oil leaks in this area risks sudden timing belt failure.
#4. Excessive Exhaust Smoke.
A worn or slipping timing belt can cause excessive exhaust smoke as improper valve timing affects combustion efficiency and allows unburned fuel to reach the exhaust system.
The smoke may appear black, blue, or white depending on the specific timing issues and their effects on combustion.
When timing belt stretch retards valve timing, the exhaust valves may not open fully during the exhaust stroke, trapping some burned gases in the combustion chamber.
This trapped exhaust mixes with the incoming air-fuel mixture, reducing combustion efficiency and creating excess emissions.
Black exhaust smoke typically indicates rich fuel mixtures caused by poor combustion efficiency from timing problems.
Blue smoke may result from oil consumption if timing issues affect cylinder sealing, while white smoke can indicate coolant burning if timing belt failure affects the water pump.
The exhaust smoke from timing belt problems often worsens under acceleration or load, when precise timing becomes most critical for efficient combustion. You may also notice reduced fuel economy accompanying the visible smoke emissions.
Monitor your exhaust emissions carefully, as sudden changes in smoke production can indicate developing timing belt problems. Combined with other symptoms, exhaust smoke changes provide important warning signs of timing belt deterioration.
#5. Engine Fails to Start.
Complete timing belt failure prevents the engine from starting, as the camshaft can no longer rotate to operate the valves.
You’ll hear the starter motor cranking normally, but the engine won’t fire because the valves remain closed and no air-fuel mixture can enter the cylinders.
This complete failure scenario represents the worst-case outcome for timing belt problems, often resulting in extensive internal engine damage in interference engines.
The continuing rotation of the crankshaft while the camshaft stops can cause pistons to collide with valves, creating thousands of dollars in repair costs.
Before complete failure, you might notice increasingly difficult starting, longer cranking times, or intermittent starting problems as the timing belt stretches and timing becomes inconsistent. These early warning signs provide opportunities for preventive replacement.
In some cases, partial timing belt failure allows the engine to start but run very poorly, with severe misfires, no power, and potential internal damage occurring with each revolution.
Stop driving immediately if the engine starts but runs extremely rough after suspected timing belt problems.
Never attempt to continue operating an engine that won’t start due to suspected timing belt failure. Have the vehicle towed to prevent additional damage that occurs when trying to force-start an engine with timing belt problems.
#6. Loss of Power During Acceleration.
Timing belt stretch or wear creates noticeable power loss during acceleration as improper valve timing reduces engine breathing efficiency and combustion effectiveness.
You’ll notice the engine feels sluggish, hesitates during acceleration, or fails to respond normally to throttle input.
As the timing belt stretches, valve timing becomes retarded, meaning valves open and close later in the engine cycle than optimal.
This timing disruption reduces the engine’s ability to breathe efficiently, limiting power output and creating the feeling of reduced performance.
The power loss may be more noticeable during highway merging, hill climbing, or other high-load situations where maximum engine output is needed.
You might find that the engine requires more throttle input to achieve the same acceleration you’re accustomed to.
Fuel economy often suffers along with power output, as the engine works harder to produce the same performance level.
The computer may also advance ignition timing to compensate, potentially causing knock or ping under load if timing belt problems continue to worsen.
Pay attention to gradual power loss that develops over time, as this pattern often indicates timing belt stretch rather than sudden component failure. Early detection and replacement prevent progression to complete failure and potential engine damage.
#7. Check Engine Light Activation.
Modern engines monitor camshaft and crankshaft positions constantly, triggering check engine light activation when timing belt problems cause inconsistencies between these critical sensors.
The engine computer can detect even slight timing variations that indicate developing timing belt issues.
Common diagnostic codes related to timing belt problems include P0016, P0017, P0018, and P0019, which indicate camshaft and crankshaft correlation errors.
These codes specifically point to timing discrepancies that often stem from timing belt stretch, wear, or impending failure.
The check engine light may illuminate intermittently at first, becoming more frequent as timing belt problems worsen. Modern engines may also enter reduced power mode to protect against damage when significant timing inconsistencies are detected.
Professional diagnosis with a scan tool can reveal specific timing-related codes and real-time sensor data that help confirm timing belt problems.
This diagnostic information proves invaluable for determining whether timing belt replacement is necessary before complete failure occurs.
Never ignore check engine lights accompanied by other timing belt symptoms, as these codes provide early warning of developing problems. Have diagnostic codes read and analyzed promptly to determine if timing belt service is needed.
Causes of Timing Belt Failure
While every timing chain will eventually need to be replaced if you drive the vehicle enough, there are certain situations and conditions that will accelerate the wear and tear your chain experiences.
In this section, we’ll break those down for you to help ensure that you’re able to maximize chain life and delay any potential damage.
#1. Lack of Oil Changes.
Engine oil is responsible for lubricating the moving parts of your engine. That includes the timing chain and the gears/sprockets that it attaches to. If you don’t change your oil on time, this can cause wear and tear and shorten the lifespan of your timing chain.
The problem is that as oil ages, it is exposed to high heat and naturally-occurring detergents from gasoline. These reduce oil’s ability to lubricate (called viscosity).
Your engine oil will also become thicker over time and will coat less and less. Eventually, the timing chain may be left unprotected from metal-on-metal wear. When this occurs, you can expect wear and tear to accelerate dramatically.
#2. The Wrong Engine Oil.
Another problem is using the wrong engine oil in your car. While all engine oil types perform the same function, they are not the same. You should use the oil weight recommended by the automaker for your specific model.
This information should be available in the owner’s manual or on the oil filler cap under the hood. Engine oil is rated by weight, which can be misleading for some. It’s a measure of thickness/viscosity.
For instance, 0W20 flows like 0-weight oil (very thin) during the summer and like 20-weight oil in the winter (thicker). In comparison, 5W20 flows like 5-weight oil in the summer and 20-weight oil in the winter.
Using oil that does not have the right flow characteristics for your engine can mean starving the timing chain of oil or coating it in oil that’s too thick and reducing its performance.
Always use the automaker’s recommended oil for your vehicle. If you’re unsure what it is, ask the mechanic at your next oil change.
#3. Towing/Heavy Loads.
The more work the engine must do, the more wear and tear moving parts like the timing chain will incur. This is especially true when it comes to towing or hauling heavy loads. The more weight the engine must move, the harder it must work.
This adds stress and load to the engine and the timing chain. In some cases, you may even hear the chain rattling when the engine is under a heavy load, particularly if the chain is nearing the end of its life.
However, don’t assume that if you don’t hear a rattle your chain is fine. Always follow the automaker’s recommended schedule of services, particularly when it comes to replacing your timing chain.
#4. Failing/Faulty Tensioner.
Like the engine’s serpentine belt, the timing chain also has a tensioner. Its purpose is self-explanatory – it provides tension to keep the chain taut and prevent it from jumping. There are two types of tensioner used today: hydraulic and spring-loaded.
If the tensioner fails, it will no longer hold tension on the timing chain. Depending on the situation, this can lead to a rattling sound, but it could also allow the chain to jump and cause the engine to shift out of time.
In that case, you may experience backfires and the check engine light will usually come on. Depending on the situation, this may also cause your engine to idle rough, or put your car into “limp home” mode.
This is a security feature that reduces the load on the engine by cutting off nonessential systems, like air conditioning, as well as limiting the speed of the vehicle.
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.
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.
How to Change the Timing Belt?
Suppose you noticed any of the outlined symptoms above and found out that the timing belt needs replacement after an inspection or exceeded the manufacturer’s replacement date.
In that case, you have to follow the steps below and replace the belt. You will need proper mechanical tools to carry out this maintenance.
Tools and Other things needed:
- Underwood work light
- Ratchet and standard sockets
- Torque wrench
- A timing belt (you can get this complete timing kit if you’re doing a complete job)
- Park your car: park your car on the firm and level ground. Engage your hand brake.
- Remove the battery terminals: Remove the battery terminals to avoid any spark during this maintenance.
- Remove the drive belt: you have to remove the drive belt out of the way.
- Remove engine accessories: The alternator, the power steering pump, AC compressor may be blocking the timing cover.
- Remove any engine mount that may be blocking your way: you have to uninstall any engine mount on the way, you will have to support your car with a jack stands.
- Remove the crankshaft pulley: This is very important you unbolt the crankshaft pulley bolt and get it out of the way. If you’re working on a manual transmission car, you have to break free the crankshaft pulley bolt before removing the drive belt. The pulley might prove stubborn to pull off. You can get a pulley removal tool for a few bucks and get the job done without much stress.
- Unbolt the timing cover bolts: Grab your wrench and the right socket size and break free the bolts. Unscrew them with your hand.
- Mark the timing marks: you want to mark the cam and valve cover, the crank, and the oil pan, so you don’t forget the timing. But if you have to turn the engine after removing the timing belt, you have to turn your engine to TDC, learn and mark the timing marks.
- Release the timing belt tensioner: Release the timing belt tensioner so you can easily take off the timing belt.
- Remove the old timing belt: Get the old timing belt out of the way.
- Install the new timing belt: Install the new timing belt and ensure that it is well-aligned with the pulleys. You can a complete timing kit so you can replace any other components that need replacement.
- Reinstall the timing cover: Fix the timing cover in place and torque down the bolts.
- Reinstall the crankshaft pulley: Reinstall the crankshaft pulley and torque it according to the manufacturer’s spec. Then, reinstall any other accessories that you removed earlier.
- Reinstall the Drive belt: Reinstall the drive belt the same way you removed it. Ensure the belt is well-aligned on the appropriate pulleys.
- Start your engine and confirm your work: well-done if you get this right. You can start your engine and allow it to idle before hitting the road.
When Should a Timing Belt Be Replaced?
A timing belt is one of those things that’s critical to replace according to the auto manufacturer’s schedule. Most often this will be between every 75,000 and 100,000 miles. Check your owner’s manual for the exact schedule for your vehicle.
Replacing your timing belt is not one of those things you can just put off indefinitely. Eventually, the belt will break and you may have thousands of dollars in engine damage. It’s simply not worth the risk.
Timing Belt Replacement Cost
We recommend Parts Geek for the best prices and selection. When you realize that it’s time to replace your timing belt, the total cost will likely put a dent in your wallet.
Because a timing belt job usually includes replacing the water pump, belt tensioner, and idler rollers (in addition to the belt itself), the total replacement cost will be between $800 and $1,100 on average.
The price will be on the lower end for small vehicles and on the upper end for larger trucks and SUVs. Expect to pay more at a dealership vs a good independent mechanic.
While the timing belt kit itself will only cost about $100 to $150, additional parts like the water pump will add another $200 or so.
Timing belts are usually purchased in kits that contain the idler pulley(s) and a replacement tensioner. Some even come with the water pump.
The biggest expense will the for the labor costs since replacing a timing belt can take a few hours. For this reason, plan on about $600 to $800 just in labor costs.
Unless you have at least a moderate amount of auto repair experience, you shouldn’t try to replace a timing belt yourself. This is one of those jobs you should let a pro handle.
FAQs.
Q: What does a bad-timing belt sound like?
A failing bad-timing belt sounds like a ticking noise in front of your car when it starts wearing out. If the belt eventually breaks, it will give a whining noise when trying to start the engine. A whining noise sounds like no compression in the engine.
Q: How do I know when my timing needs replacement?
A few signs or symptoms will indicate when you have to replace your timing belt. So, when you notice these signs, you should inspect and change your timing belt.
- Engine misfires. Note that a lot of things will cause your engine to misfire.
- Ticking sound in front of your car. When your timing belt starts going bad, you may hear ticking sounds.
- The engine won’t start. If your timing belt break, your engine will not start. Note that several things can cause your engine not to start.
- The actual timing belt is worn out. When you notice that your timing belt is worn out, it is the right time to replace it.
- You have exceeded the recommended replacement date. If you have reached the manufacturer’s recommended date for replacement, you have to replace the belt.
Q: Can I replace the timing belt myself?
Timing belt replacement needs a professional mechanic to handle. But if you’re a good DIY, you can replace the timing belt yourself by following the step-by-step guides above.
Q: How long timing belt can last?
Well, this solely depends on the timing belt you used the last time you replaced your timing belt. However, on average, all timing belts should be replaced between 60,000 to 90,000 miles or 7 to 10 years, whether it covers the mileage or not.
All the same, I recommend you check your service booklet to know when to replace your timing belt.
Final words
At this point, you must have known jumped timing belt symptoms, symptoms of bad timing bad, and how to replace it.
However, you should note that replacing a timing belt can be a professional service and can cause catastrophic engine damages if not carried out correctly.
You should carefully follow this guide to replace your timing belt. But if you’re not coming with this guide, you can contact a professional mechanic to replace your timing belt.