Does the engine timing chain need to be replaced?

The engine needs the piston and valve to work in perfect harmony in order to keep it running normally. The timing system is the key to keeping the crankshaft and camshaft in such harmonious coordination. Some trucks use a belt to connect them, which is called a timing belt, while others use a chain, which is called a timing chain. 

We all know that the timing belt needs to be replaced regularly because it is a rubber part that is prone to aging. Generally, it needs to be replaced every 3 to 5 years or 60,000 to 100,000 kilometers, regardless of whether the belt is worn or aged. Sometimes, there is no abnormality from the appearance, but it may break at any time after its service life has expired.

The timing chain is usually made of high-strength alloy steel, which has good wear resistance and durability. So does it need to be replaced regularly?

The timing chain also needs to be replaced, but its replacement cycle is longer, generally more than 150,000 kilometers. Such a high mileage leads to people often forgetting that it needs to be replaced.

In actual use, when the chain is stretched, it needs to be replaced. The chain is made of metal, and as long as the engine is running, it will be subject to huge tension, especially when the engine is running at high speed or under heavy load, the chain will be subject to greater tension. After long-term continuous stretching, the metal material will fatigue, causing the gap between the chain links to gradually increase, thereby lengthening the overall length of the chain. This phenomenon is actually easy to understand: any object will be stretched as long as it is stretched; if the object cannot be deformed, it will not be stretched, but will break directly. 

We can know that the chain needs to be replaced from two aspects. First, the engine fault light is on, and the computer detects the fault code related to the timing. For a vehicle with a chain, if the crankshaft and camshaft are not matched accurately, a fault code will be reported to remind the owner to replace it. Second, the chain makes a sound, mainly when idling, which is generally a rattling sound, like the sound of metal hitting each other.

What are the consequences if you don't change it? 

First of all, if the chain is too loose, it will cause the piston and valve to deviate from each other, which will affect the compression ratio and ignition time of the engine, resulting in a decrease in engine power, incomplete combustion, increased fuel consumption, and increased carbon deposits.

If the chain breaks directly, the valve and piston will collide with each other more seriously, causing damage to many parts.

The replacement cycle of the chain is related to the quality of the chain and the use of the vehicle. If the vehicle is used in a harsh environment, with frequent rapid acceleration and deceleration, which causes a large impact on the chain, or if the vehicle is often loaded with heavy objects, causing the engine to run under heavy load, the life of the chain will be shortened.

When a vehicle is driving at high speed, if the engine suddenly fails due to a chain problem, it may cause a traffic accident and threaten the safety of the driver and passengers. Therefore, timely replacement of the timing chain is not only a maintenance of vehicle performance, but also a responsibility for personal safety.