5 Symptoms of a Bad Timing Belt Tensioner & Pulley in Your Car

The internal combustion engine contains a part called the timing belt. This is responsible for ensuring that the camshaft and crankshaft are rotating at the same time. That way, the valves of the engine will open and close when they are supposed to. The functioning of the valves is meant to be in sync with the intake strokes and exhaust strokes of the engine’s cylinders.

The two main parts of a timing belt are its durable rubber and nylon-reinforced cords. The belt is constantly coming in contact with various gears and pulleys. After a while, the belt becomes too loose because the wear and tear stretch it out. For this reason, a timing belt tensioner is used to ensure the belt remains tight. If the tensioner goes bad, then it will basically be like having a bad timing belt because it won’t be able to function properly anymore. This will create all kinds of trouble for your engine performance.

The Top 5 Symptoms

Below are the top 5 symptoms of a bad timing belt tensioner. If you notice any of these, then it is likely time to replace your timing belt tensioner at once.

Check Engine Light – If the timing belt is loose because of a bad tensioner, then the timing of the valves will be off. This means problems in the engine, which will then result in the check engine light illuminating on the dashboard.

Knocking Sounds – When the timing belt gets loose, it will start to knock around and hit the timing cover and the other parts inside of it. If it does not exactly sound like knocking, then it might be more of a slapping sound instead.

Engine Fails to Turn Over – The camshaft and crankshaft cannot synchronize when you have a loose timing belt caused by a bad tensioner. Because of this, you won’t be able to ignite the fuel and air mixture in the chamber. You may hear the motor after you turn the key in the ignition but you won’t be able to turn the engine over.

Grinding Sounds – If the timing belt doesn’t have a firm grip on the pulleys, then it will cause the pulleys themselves to make grinding or rattling noises. This will definitely happen if the pulley bearing goes bad.

Engine Misfires – If the valves of the cylinder open or close too prematurely, then it will result in an engine misfire. This will happen if the timing belt is not able to rotate the camshaft and crankshaft at the same time.

Read also: 5 Symptoms of a Bad Tie Rod End and Replacement Cost

Replacement Cost

The replacement cost of the timing belt tensioner is anywhere from $150 to $300. Parts will be about $130 while the labor will be around $90 to $150. Taxes and fees may be added to these prices.



  1. My 2011 Chevy Silverado makes a ticking noise in the mornings then when it warms up it stops and I don’t hear it anymore??

    What causes this noise

  2. I have Audi A4T and the tensioner become so that is mean my valves are damaged cause it seems like there is no compression

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