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How to Tell if Your Timing Chain Is Going Bad

Mia Bevacqua
March 21, 2018

 

Your engine relies on perfect timing. As it goes through its four strokes — intake, compression, combustion and exhaust — it relies on the camshaft to open its valves and the crankshaft to move its pistons, all without them crashing into each other. The timing chain or timing belt plays a big role in this.

Timing chains can either or stretch or break. This can cause several problems:

1. Illuminated check engine light: The car’s computer monitors engine operation to ensure emissions don’t get too high. A stretched timing chain will hurt engine performance and increase emissions. If this happens, the computer will turn on the check engine light and store a diagnostic trouble code

2. Poor engine performance: A stretched timing chain will affect valve timing. This can cause a number of engine performance problems, such as a misfire, rough running and a lack of power.

3. Engine won’t start: If the timing chain breaks, the engine won’t have compression and won’t start.

4. Engine overheating: Although rare, if the water pump is driven off the timing chain, a loose timing chain may result in engine overheating.

5. Engine failure: If the timing chain breaks or jumps time — meaning it starts skipping teeth on a gear — the valves may contact the pistons. This will damage the pistons and cause the valves to bend, ruining the engine. A loose timing chain may also slap around, smashing other components in the engine.

Get it diagnosed by a professional
 

What does a timing chain do?

The timing chain or belt attaches to the camshaft, in the top half of your engine, and the crankshaft in the bottom half, ensuring that they turn at the correct speed and time so that your engine runs smoothly. In some cases, the timing chain or belt may also drive additional components, such as the water pump and balance shaft.

Timing chain vs. timing belt

So, what’s the difference between a timing chain and a timing belt? Well, there’s the obvious — one’s a belt and one’s a chain — but each has an advantage.  A timing belt will run more quietly but will need to be replaced as part of regular maintenance every 60,000 to 100,000 miles. Meanwhile, a timing chain will make more noise but is stronger and longer-lasting. Both can cause a lot of damage to your engine if they break. 

Timing chains tended to give way to timing belts in cars made in the 1970s and ’80s, but have made a comeback in the past decade or two because of their longer life expectancy and the fact they typically give warning signs before breaking.

» MORE: How reliable is your car?

How to fix the problem

If you notice the signs of a stretched timing chain, get it replaced immediately, before it breaks. This is a sensitive procedure that can cause serious engine damage if not done correctly, so you’ll want to leave it to a professional mechanic

If the water pump is driven off the timing chain, it’s a good idea to replace the pump at the same time, as a preventative measure.

In a worst-case scenario, if your timing chain has snapped and severely damaged the engine, you’ll be facing a big repair bill. It might not be worth shelling out for, depending on the age of your car and the amount of miles on it. Get an estimate from your mechanic, do the math and determine if you would be better off buying a different automobile.

 

Mia Bevacqua

About the Author

Mia Bevacqua is an automotive expert with ASE Master, L1, L2 and L3 Advanced Level Specialist certification. With 13-plus years of experience in the field, she applies her skills toward writing, consulting and automotive software engineering.

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