5 Symptoms Of A Failing Idler Pulley
Here are five common signs that indicate idler pulley issues:
1. Chirping Or Whining Noise From The Engine
Engine noise due to idler pulleys can be attributed to three possible situations:
- An Old Or Worn-Out Pulley: When the pulley starts to wear out, it may make a squeaking or chirping noise due to rubbing against the engine drive belt (sometimes called engine belt or accessory belt).
- Pulley Slippage: Once the pulley is sufficiently worn out and starts slipping, you’ll hear a whining or squealing noise that worsens as the damage increases. Pulley slippage can lead to other issues like drive belt and alternator trouble.
- Pulley Damage: A worn-out pulley will get damaged and form cracks after a certain point. In that case, you’ll hear an even louder and continuous squealing noise. It may eventually break apart and cause the serpentine belt to tear and break as well.
In other words, the noise from a failing idler pulley will increase as the damage increases. So, it’s best to have the part checked while the pulley noise is light.
2. Illuminated Check Engine Light
Generally, an illuminated check engine light won’t turn on to indicate a failing idler pulley. However, it may turn on due to the effects of a busted idler pulley.
What triggers the check engine light?
A broken idler tensioner pulley can cause a displaced drive belt, leading to a series of other issues, including alternator failure. The check engine light would be triggered as soon as the drive belt slips off.
So, the check engine light could be a symptom of a damaged idler tensioner pulley.
3. Reduced Vehicle Performance
The idler pulley is a component of the serpentine belt system that drives important elements like the alternator, power steering (via the power steering pump), and water pump.
That’s why a bad pulley will hamper a vehicle’s performance and needs immediate servicing.
Note: Some older vehicles have a separate fan belt and alternator belt rather than a single serpentine belt connected to all the engine accessories.
4. Visible Wear And Tear
A visual inspection of the engine belt, especially if you hear a chirping engine noise, can help you determine if you need an idler pulley replacement.
Look out for abrasions and scoring marks on the pulley or damaged pulley bearings. This wear and tear could eventually lead to pulley seizing or a pulley breakdown.
Alternatively, you could have a mechanic take a look at your engine bay if you suspect pulley damage.
5. Drive Belts Stop Working
A failed idler pulley can affect the rotation of the accessory belt and may even cause the belt to slip off and stop working.
So how do you know when you have a faulty drive belt?
Most probably, the check engine light will be illuminated, and you’ll need to inspect the engine. Your car may have a stalled engine with an undone or broken drive belt. But even if the engine can run without the belt, it’ll overheat as the water pump will stop functioning.