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Summary
  • The timing belt tensioner secures the timing belt and keeps it tensioned.
  • There are hydraulic and mechanical timing belt tensioners.
  • The symptoms of a bad timing belt tensioner include an illuminated check engine light, engine performance problems, starting problems, and noises from the engine.
  • Driving with a bad timing belt tensioner can damage the engine.

Vehicles have a timing belt or a timing chain inside their engine that’s partnered with a timing belt tensioner. While timing belt tensioners are generally built to last for a long time, they can still fail. When they do, it can cause an array of engine problems. In this article, you’ll learn about the symptoms of a faulty timing belt tensioner so that you can fix it before it worsens.

What Does a Timing Belt Tensioner Do?

To understand the purpose of the timing belt tensioner, you’ll first need to learn about the timing belt. This part connects the crankshaft and camshaft, which are separate components at the top and at the bottom of the engine. The timing belt is also responsible for keeping these parts in sync. The crankshaft is connected to the connecting rod and piston assembly, while the camshaft controls the intake and exhaust valves.

timing belt tensioner
The timing belt tensioner connects the crankshaft and camshaft, and is also responsible for keeping these parts in sync.

The timing belt tensioner secures the timing belt and keeps it tensioned. Since the timing belt can stretch out over time, the tensioner pushes on a segment of the belt to ensure that there isn’t any slack. Slack can cause the belt to slip on the pulleys or even come loose, which would cause a number of engine problems.

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There are two types of timing belt tensioners. Hydraulic tensioners use a piston to push on a lever or arm attached to the belt, while mechanical tensioners use a spring or a special tool instead to achieve the same result.

Bad Timing Belt Tensioner Symptoms

Your vehicle might have a faulty timing belt tensioner if it exhibits one or more of the following symptoms.

Note: Other problems can mimic a failed timing belt tensioner. You or your mechanic should perform a thorough diagnosis before conducting any repairs.

Illuminated Check Engine Light

The engine timing is constantly monitored by the powertrain control module (PCM) through the crankshaft and camshaft sensors. If the timing belt develops issues, the PCM will detect the timing changes and turn on the check engine light. It will also store a diagnostic trouble code.

Engine Performance Issues

To function properly, engines need a spark, a specific combination of air and fuel, and sufficient compression. Faulty timing belts can’t open and close valves at the appropriate timing, resulting in a loss of compression. This results in an engine that performs poorly. Your vehicle might also have misfires and a rough idle.

Starting Problems

If the timing belt tensioner fails, it might cause the timing belt to break or become too loose to turn the camshafts. If this happens, the engine may not even start because the valves are open when they shouldn’t be, resulting in valve-to-piston contact and catastrophic engine failure.

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Various Noises Coming from the Engine

When the tensioner becomes faulty, the belt and pulleys can generate high-pitched whining or chirping noises due to the belt rubbing on the pulleys. If the tensioner fails completely, the noise might escalate into squealing or grinding. If the timing belt tensioner is driven by oil, the noise might be most prominent during start-up, when oil is just beginning to circulate throughout the engine.

Catastrophic Engine Failure

If some engines don’t have proper valve timing because of a faulty timing belt tensioner, then it can cause the valves to hit the cylinder, which can cause catastrophic engine failure. These types of engines are called interference engines. Faulty valve timing in these types of engines can cause catastrophic damage and require an engine replacement.

Timing Belt Tensioner FAQ

What Causes Timing Belt Failure?

A timing belt is typically made of rubber material with teeth on one side that transfers torque between various engine components. The rubber material will wear out with age and mileage due to the heat and friction inside the engine.

Rubber teeth can wear down and no longer be able to grip the gears. This frequently results in the timing belt sliding, which can potentially damage the engine. The belt can also crack under stress. The material can also crack because of mileage and age.

Where to Get A New Timing Belt Tensioner for Your Vehicle

A faulty timing belt tensioner isn’t the end of the world, but it will cause many problems for you and your vehicle. Your vehicle might display engine performance issues, make strange noises, and even have difficulty starting your vehicle. Fortunately, with the help of CarParts.com, finding a replacement timing belt tensioner is a breeze.

All you need to do is use your mobile phone to visit our website at CarParts.com. Input your vehicle’s details into the selector, including the exact year, make, model, and engine. This way, you can easily check out our vast collection of compatible timing belt tensioners.

Our parts are sourced from some of the best manufacturers in the industry. They’re available at unbeatable prices to help you get more bang for your buck. We ship them from warehouses strategically located across the US to guarantee fast and reliable shipping.

With this in mind, it’s better to get your timing belt tensioner replaced sooner rather than later. Check out our collection of quality timing belt tensioners at CarParts.com to help you get started with your vehicle’s repairs.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He’s an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Reviewed By Technical Reviewer at CarParts.com

Tony Harlin is a Master Gas and Diesel Diagnostic Technician with over 18 years of experience. He works full-time at a large independent automotive shop as a driveability and repair technician working on all types of vehicles with a focus on diesels. ASE certifications include A1-A9, L1 and L2, as well as X1.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : DIY , Engine Tagged With :
Garage Essentials
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