Timing Chain Symptoms: 5 Things To Look For A Failing/Stretched Timing Chain

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Timing chains are essential to an engine’s operation, keeping the engine’s valves and pistons in sync. 

A timing chain that is in working order is crucial for the engine’s performance, fuel efficiency, and longevity. 

However, suppose the timing chain starts to fail/stretch. 

In that case, it can lead to significant issues like engine misfires, engine not starting, metal-on-metal sound, engine warning light, and poor fuel efficiency, leading to an engine failure that requires costly repairs.

This article will discuss the failing/stretched timing chain symptoms and what to do if you suspect your engine is experiencing issues.

a typical double over head cam engine with variable valve timing and timing chain
A Typical double-over-cam timing chain setup.

5 Failing/Stretched Timing Chain Symptoms

Engine Misfire

An engine misfire is one of the most common symptoms of a failing/stretched timing chain. 

This happens when the timing chain is not correctly synchronizing the engine’s valves and pistons, leading to a non-ideal engine ignition resulting in the spark plug igniting the fuel while one of the valves is still open. 

The result is an engine that sounds rough and sputters during operation.

Engine Not Starting

If your timing chain is failing/stretched very severely can cause the engine not to start at all.

The crank and valve timing are so out of sync that the ECU won’t let the injectors spray fuel to save the engine.

On Older Vehicles running carburetors, this scenario won’t happen since the vehicle does not have an ECU.

Metal-on-Metal Sounds

A failing/stretched timing chain can also produce a metallic rattling or knocking noise from the engine. 

This sound is typically heard only at startup because the timing chain vibrates against the timing chain tensioner guides while the engine oil pressure builds up to tension the chain.

If the sound doesn’t stop while idling, the timing chain is on its last legs and must be replaced as soon as possible.

Usually, this is the first sign the timing chain needs replacement.

Here is an excellent example of the noise you will hear from a stretched/failing timing chain:

1.2 TSI faulty timing chain rattle

Engine Warning Light

If your vehicle’s timing chain is experiencing issues, your engine warning light may turn on. This happens when the timing chain is so stretched that it causes the crank and cam timing to be so out of sync that the vehicle’s ECU will turn on the warning light and even reduce engine power.

Poor Fuel Efficiency

A stretched or failing timing chain can also lead to poor fuel efficiency. 

If the engine’s valves and pistons are not synchronized correctly, the engine may not be able to burn fuel efficiently, leading to a decrease in fuel economy.

a pushrod V engine with timing chain and tensioners
A typical overhead valve (pushrod) timing chain setup.

Final Thoughts On Timing Chain Symptoms

If you experience these symptoms, bringing your vehicle to a trusted mechanic is crucial. 

However, ignoring the issue can lead to further damage to your engine, resulting in costly repairs or a complete replacement.

In most cases, a failing or stretched timing chain can be replaced by a trusted mechanic or DIY if you are okay with delving into engines.

Here is a video of HumbleMechanic doing a timing chain replacement on a Volkswagen 2.0 Turbo 4 cylinder as an example:

How To Properly Time and Install Timing Chains on a TSI Engine

Therefore, it is essential to maintain your engine’s timing chain and other components regularly to prevent premature failure.

Hopefully, you found this article helpful and will prevent your vehicle from getting costly damages.


What Does A Failing Timing Chain Sound Like?

It sounds like a metallic rattling or knocking sound coming from the front of the engine.
The longer you ignore it, the louder and more severe the sound will become as it starts eating away at the edges of the timing chain tensioner guides until the chain snaps and experiences engine failure.

What Happens When A Timing Chain Goes?

Catastrophic engine failure is caused when the timing chain fails.
This is due to the engine spinning at idle speed or more, and suddenly the valvetrain stops causing the piston to hit the open valves, bending them and/or damaging the piston and combustion chamber.

How Much Does It Cost To Fix A Timing Chain?

A timing chain replacement can cost $400 if you are willing to do it yourself to upwards of $6,000.
Engine layout, placement, manufacturer, and year of production can alter the pricing of the timing chain.
An econobox inline four-cylinder will be cheaper than a luxury vehicle with a V8 or V12, and the older the car gets, the more scarce the parts become.