Any strange noise from the engine is concerning! If you hear rattling and clanking, pull over! It may be your timing chain. What is a timing chain? What kind of noise does it make? How can you diagnose the problem?
A timing chain connects the crankshaft to the camshaft in a combustion engine. It is an important component that allows the valves in the engine to open and shut for intake and exhaust. If the timing chain is faulty, it makes a metallic rattling sound. This could be due to wear and tear, damage, low or old oil, or a faulty oil filter.
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What is a Timing Chain?
A timing chain may also be called a timing belt, or a cambelt. Its purpose in the engine is to connect the crankshaft to the camshaft. This opens and closes the valves during the intake and exhaust strokes in a combustion engine.
Types of Timing Chains
Timing chains are usually made of metal or rubber-coated metal. A timing chain is usually more durable, but also may make more noise while driving.
A timing belt is made of rubber composite. This belt has teeth that fit against the gears on the crankshaft and camshaft. Rubber timing belts are much quieter than timing chains, but they usually need to be replaced more often.
How a Timing Chain Works
The crankshaft turns and the timing belt starts to move. Since the timing belt connects the crankshaft, and the camshaft, as the timing belt moves, so does the camshaft.
When the camshaft turns, it opens or closes each valve and moves the pistons up and down. The timing belt or chain controls the timing of the intake, compression, combustion, and exhaust phases in the engine. Precise coordination is needed to make sure the engine runs!
What Does Timing Chain Noise Sound Like?
Since the timing chain is located in the engine, the sound will come from the engine compartment. It will usually sound like a rattling or metallic clanking sound. Think of the sound of metal on metal contact. Some people describe the sound as a metallic slapping noise.
The noise is usually the loudest when the car first starts and the engine is relatively cool. You may notice the sound becomes fainter or stops altogether as the engine and the chain both warm up.
What Causes Timing Chain Noise?
There are quite a few possible causes of timing chain noise! Assess your vehicle to diagnose the cause of your timing chain noise.
Stretched Timing Chain
With time and wear and tear, the timing chain can stretch out. Once it is stretched out, it won’t fit as tightly over the gears while it turns. You will hear a loose, metallic sound as the chain is in motion.
Worn Bearings or Sprockets
If the bearings or sprockets are worn, the chain will not engage with the crankshaft and camshaft correctly. The chain will sound like it is slipping as it fails to grab the gears.
If the chain is stretched, or the bearings are worn, the chain may jump from the correct position. If this happens, you may hear an initial loud, metallic clank, then the engine will stop.
Broken Timing Chain
The car will not run with a broken timing chain. You may be able to hear it rattle in the engine as it snaps. Look in the engine compartment for the pieces of the chain.
Old or Low Oil
The oil circulating in the engine compartment lubricates the timing chain. If the oil is low, or the quality of the oil is diminished, you may hear timing chain noises.
The oil normally flows between the timing chain and the gears. Without that lubrication, the metal pieces will make contact with each other. It is important to change the oil regularly to keep your car running smoothly.
Check your car’s manual to see what grade and viscosity of oil to get. The wrong oil may not lubricate the engine and the timing chain correctly. Look for a synthetic oil for the best results. Synthetic oil may be a little more expensive but it has anti-wear additives.
Bad Oil Filter
The flow of oil can also be disrupted by a bad oil filter. If the oil isn’t flowing well through the engine, the timing chain will not be well lubricated and may make noise. A quality oil filter is worth the investment! Make sure you replace the filter as recommended.
Don’t let a rattling engine ruin your day! Listen carefully to diagnose the issue with your timing chain. Once you determine the problem, it can be fixed and you will be back on the road again in no time!