alics Blogs

Knowing about serpentine belt

Most new engines are equipped with serpentine belt drives for engine driven accessories. Most people know that the belt is a maintenance product, and it will eventually be replaced. However, many people do not know that the spring-type automatic tensioner that keeps the serpentine belt tight is also a kind of wear item. Therefore, when the belt needs to be replaced, the automatic tensioner may also have to be replaced.

There is a coil spring inside the automatic tensioner, which can exert proper force on the belt to keep the belt tight. The tensioner also provides a little “given”, so it can absorb and buffer the impact load on the belt when the A/C compressor clutch cycle is opened and closed. More importantly, the tensioner will automatically compensate for wear and keep the belt under constant tension. But nothing can last forever, neither the belt nor the automatic tensioner. The typical service life of the serpentine belt is about 60,000 miles or five years. When the belt approaches its service life, it may have cracks, glaze and noise. Often, we need to consider quality belt and tensioner pulley bearing from China Tensioner Pulley Bearings manufacturers.

If the aging belt is not replaced, it may break, resulting in the loss of driving torque of all engine accessories. When the water pump stops rotating, the coolant stops flowing and the engine starts to overheat. When the alternator stops rotating, there is no charging output and the battery starts to run out. When the power steering pump stops rotating, the steering suddenly becomes very stiff and difficult to control.

Symptoms that usually indicate that the automatic tensioner has reached its end include:

The tensioner moves excessively or swings or “belt vibrates” when the engine is running. This means that the spring in the tensioner is weak and/or the bushing is worn. The tensioner needs to be replaced.

Tensioner (or idler) swings. Swing means the bearing is hit.

Belt or tensioner noise. The tensioner should be quiet when the engine is running. Any screams, rumbles, growls or whistles should be investigated to determine the cause. The mechanic’s stethoscope can be used to identify the noise source. The probe should be placed on the bolt in the center of the tensioner to listen to the bearing noise. The idler gear should also be checked because the bearings in this component are also worn.

The pulley is damaged. Any type of physical damage on the automatic tensioner may indicate excessive tension or physical interference. If the pulley is damaged, replace the tensioner assembly, not just the pulley. If the idler gear is damaged, also check the tensioner, because the vibration caused by the damaged idler gear may damage the tensioner. China tensioner pulley bearings manufacturers provide quality tensioner pulley bearings.

Tensioner inspection always important

Check the movement of the tensioner arm with the engine off. Use a sleeve with a long handle ratchet or circuit breaker lever on the central bolt of the tensioner to rotate the tensioner. There is no specification to measure the resistance provided by the tensioner spring, but if the resistance provided by the tensioner is very small, it may indicate that the spring is weak or damaged. If it cannot move at all, the tensioner is stuck and needs to be replaced.