Idler pulleys or engine pulleys are vital for the engine drive belts in a vehicle. The idler pulleys guide the engine drive belts through different major engine components. With the presence of idler pulleys, it becomes easier for the engine belt to loop around all the components via the correct route. Hence, if your vehicle has a bad idler pulley, then it will affect the function of the AC compressor, water pump, alternator and power steering pump. 

Idler pulleys tend to fail over time and should be replaced at the earliest. But, how to tell if you have a bad idler pulley? Let’s go through the symptoms of a faulty idler pulley that will help you take proactive measures. 

SYMPTOMS OF BAD IDLER PULLEY

Here discussed are the common signs of a bad idler pulley:

SQUEALING SOUND FROM ENGINE BELT   

One of the common bad idler pulley symptoms is when the engine belts start producing a squealing sound. When the pulley seizes, or the surface is worn-out, then there is a squealing noise as the engine belt rubs against its surface, due to the absence of enough motion from the pulley, a squealing sound is produced.  

Also, if the faulty idler pulley slips or binds, the engine belt will yield a squealing sound when you start the engine. 

Besides, squealing sound is one of the car sounds that motorists should never ignore, as its a sign of a problem in your vehicle and needs to be fixed.

WORN OUT SURFACE 

When you start hearing squealing sounds, it is advised to look for any wear on the idler pulley. If you come across scoring marks, then it’s one of the signs of a bad idler pulley. The first thing you should do is replace it to prevent the engine belt from losing tension and slipping. Like any other component in the vehicle, the idler pulley surface is also worn out over time due to non-stop rotation. Hence, simply get it replaced. 

FAULTY BEARING OR PULLEY 

You can easily identify if the idler pulley or bearing is damaged to an extent that they may break apart or crack. This type of damage is quite visible and may affect the function of the engine. Also, the engine belt may fall off that may cause engine overheating or stalling. 

Belt Conveyor Idler

EXCESSIVE SPINNING

When you are looking for visible damage on the idler pulley, spin it. A properly functioning idler pulley will stop after spinning for a few rotations. But, if the pulley continues to spin then its one of the bad idler pulley symptoms and indicates a problem with the bearing. Also, you may hear a noise even at normal RPMs.

IDLER PULLEY DOES NOT SPIN OR SPINS SLOW 

A properly functioning idler pulley spins without any resistance and stops after a few rotations. However, a bad idler pulley will not spin and bind up. If this is the case, get the idler pulley replaced. Besides, if the faulty idler pulley is on any of the engine components, then the component will also need to be replaced. 

HOW LONG CAN YOU DRIVE WITH A BAD IDLER PULLEY? 

You can easily drive your vehicle for tens of thousands of kilometres with a bad idler pulley, until the engine components continue to function normally. But, if the engine belt slips then you may lose control of the vehicle while driving. 

WHEN AN IDLER PULLEY SHOULD BE REPLACED?

An idler pulley can wear out over time and fail completely. The time for an idler pulley to wear out varies. However, it needs to be replaced after a car covers approximately 80,000 to 160,000 km. The time to replace idler pulleys also depends on the time when the accessory or serpentine belt is replaced last time. 

HOW TO PREVENT IDLER PULLEY FROM GOING BAD

Since idler pulleys rely on bearings, there is not much that can be done to prevent them from failing. bad. Bearings wear out over time and hence, damage the pulley. However, regularly cleaning the car engine may help keep up the performance of the idler pulley and extend its life.  Moreover, there are many mechanical benefits of engine cleaning. 

When you replace components in the engine, don’t opt for low-quality parts just because they are affordable. Low-quality parts corrode and wear out faster and may affect the function of other parts linked to it. 

The idler pulley is vital to the function of the engine. The working of many engine components depends on the idler pulley and the drive belts. Hence, if your vehicle indicates any bad idler pulley symptoms then head to an auto service centre at the earliest.  Besides, when buying a used car in the UAE, don’t forget to check the symptoms of a bad idler pulley, discussed above.