What Is a Timing Chain?

The engine timing chain or valve timing chain is a type of roller chain found in the internal combustion engine. 

What does it do?
It synchronizes your vehicle’s crankshaft and camshaft(s). This allows your intake and exhaust valves (operated by the camshaft) to be timed correctly with the pistons (driven by the crankshaft) — resulting in proper fuel combustion.

Some modern engines feature variable valve timing technology that adjusts the timing of valve opening and closing to different car engine speeds and load conditions. This precise variable valve timing system optimizes engine performance, fuel efficiency, and emissions.

Additionally, the timing chain may also drive engine components like the water pump and fuel injection systems in certain engines. 

Note: Some cars use a timing belt instead of a timing chain.

When Should I Replace a Timing Chain?

It’s a good idea to have a timing chain replacement between 80,000-120,000 miles. 

Timing chains are highly durable and are designed to last your vehicle’s lifetime, however, wear and tear can happen with time — especially in cars with high mileage.

What Are the Symptoms of a Defective Timing Chain?

Here are a few warning signs that indicate timing chain problems:

• An illuminated check engine light: If you’re experiencing valve timing chain problems, your car engine computer will detect the issue and trigger the check engine light. Depending on the timing chain component that prompted the warning, it’ll likely store a faulty timing chain-related trouble code, like P0011 or P0012. 

• Engine noise: A bad or loose timing chain often makes a whirring or rattling noise. Damage to related components, like chain guides or a tensioner, will also produce whining or buzzing noises near the timing chain cover region. 

• Poor engine performance: A stretched timing chain can disrupt the synchronization between the camshaft and crankshaft, leading to incorrect valve timings and incomplete combustion. As a result, the engine may misfire, idle, or feel sluggish. 

• Metal shavings in your oil: Tiny metal bits can shear off a worn timing chain. Small metal pieces in your engine oil, when drained or found in the oil filter, could mean your timing chain needs a replacement.

How Urgent Is a Timing Chain Repair?

If you suspect a damaged timing chain, get it fixed ASAP. 

If they wear out or become loose, it’ll disrupt the engine’s functioning and even shut it down without warning while driving.

You may not always have a broken timing chain. But if it does break, a broken timing chain can destroy your engine.

For instance, some engines with timing chains are “interference” engines. This means the engine valves and pistons move in and out in the same cylinder space. 

When the timing chain breaks, the engine valves won’t move out of the way, and the pistons will smash into them, possibly resulting in a catastrophic engine failure.

How Much Does a Timing Chain Replacement Cost?

A timing chain replacement typically costs between $1,600 to $ 2,000 (parts and labor included.) The actual timing chain replacement amount depends on your vehicle’s make and model and local labor charges.  

The timing chain itself costs around $100-$250, but a timing chain kit can go up to $500. A proper timing chain kit will include gears, a chain tensioner, and sometimes even the water pump. 

Labor costs can fall around $950 to $1,200. That’s because replacing a bad timing chain is complicated, and any mistakes in the timing chain setting can cause severe engine damage. 

This explains the costly repairs as well as why you shouldn’t DIY and get a professional to handle the repair.

3 Timing Chain FAQs

Here are answers to some commonly asked questions on timing chains:

1. Is a Timing Chain the Same as a Timing Belt?

Timing belts and timing chains have the same function — they connect the engine’s camshaft and crankshafts. 

However, here’s how they differ:

• Timing chains are made up of metal and located inside the engine (so they can be lubricated with engine oil). They generally last longer, saving costs in the long run. 
• Timing belts are situated outside the engine and are made up of rubber. They are also quieter and cheaper to manufacture. A rubber timing belt requires more frequent replacement than a timing chain.

2. Why Does a Timing Chain Break?

It’s rare for a timing chain to break. However, accelerated wear can happen when the vehicle doesn’t stick to scheduled oil changes.

Why?
The engine oil helps in the lubrication of the timing chain, so regular oil changes promote its longevity. 

A defective timing chain tensioner, chain cover, or guide can also damage the timing chain. It can result in a free or loose timing chain that will slap against other engine components — leading to costly repairs.

Note: A rubber timing belt is more likely to break than a timing chain.

3. Is It Worth Fixing A Timing Chain?

Assuming you want to keep driving your vehicle, then yes. 

While replacing a worn timing chain isn’t easy or cheap, it’s still less expensive than replacing an engine due to a broken timing chain.