Car Making Whistling Noise – What Does This Mean?

A whistling noise while driving is a common problem. The noise can be caused by a loose belt, a worn belt, or a bad water pump. The sound of the belt in question will vary depending on whether it’s worn or not.

A worn belt will make an uneven sound at all speeds because it has stretched and no longer fits snugly around its pulley wheel.

A loose belt will make more of an intermittent rattling sound as it rubs against other parts on your vehicle’s engine block when one wheel turns faster than another during acceleration or deceleration (e.g., going up steep hills).

Most times, you can hear a car whistling noise while driving, accelerating, decelerating, or braking.

You hear a whistling noise during idle or when you’re coasting and letting off the gas pedal to bring the car to a stop (sometimes called “spark knock”). This is quite similar to when your car makes whirring noise when slowing down.

It is most common in older cars with carburetors and poor fuel quality. The harder you press on the brakes, the higher-pitched the whistle becomes as more air passes through it at higher speeds; newer cars use electronic fuel injection systems and don’t have this issue as often.

Why Is My Car Making A Whistling Noise?

1. A Loose Serpentine Belt Tension

Check the belt tension. If it’s loose, replace it. If it’s too tight, loosen it. Remove the serpentine belt and lay out all of its components to see exactly how they fit together before re-attaching them to one another.

Replace the old belt with a new one that matches the dimensions of your old one, close enough for them to work together again without slipping or being too loose or tight on either side of the pulley causing whistling noises in your engine compartment.

2. A Worn Out Serpentine Belt

The serpentine belt is a rubber-covered, V-shaped piece that wraps around the engine and drives all the accessories. It will squeal or “whistle” as you drive the car. You can check for wear using two methods:

  • Look at the belt from behind your car in front of an open hood (or up from underneath) to see if there are any cracks, splits, or missing pieces.
  • Check for fraying along edges by flipping over about six inches of the belt and feeling for thinned-out spots where various sections join together (the heat from friction can cause this). If you find any flaws in your old belt, then it’s probably time to replace it before something goes wrong with one of those accessories.

Related Post: Clunking Noise When Braking

3. Dirt In The Streams of The Alternator Pulley

You may be noticing a whistling noise coming from your alternator pulley. This is a common problem and can be fixed with simple maintenance. The first step to repairing this issue is understanding how dirt might get into the alternator pulley.

There are two ways that dirt can get into the alternator pulley: 

  1. Through the belt or an opening in the front of the alternator. The most common cause of dirt getting into an engine’s belts is improper belt adjustment or misalignment issues with parts in front of or behind it (such as idler pulleys). Another possible cause could be that something is obstructing one side of its path – such as when someone puts their hand on top of their car at night without realizing that they have just removed all air circulation from underneath them.
  2. Through an opening in front of your alternator (or “vibration damper”). These openings decrease vibration by reducing friction between moving parts inside the engine compartment. However, they also enable particles like dust and sand to enter if they aren’t adequately protected against intrusions by sealing off these openings with gaskets designed explicitly for them.

4. A Worn-out Tensioner Roller

You could hear a whistling or squealing noise when you start your vehicle. A worn-out tensioner roller causes this, usually caused by a worn or broken belt. Belts need to be replaced every two years, while tensioners should be replaced every five years.

5. A Bad or Failing Water Pump

A bad or failing water pump can cause a whistling noise in the engine. Additionally, it may cause the car to overheat and stall. A leaking water pump can also cause the car to overheat and stall, or leak coolant into the oil. This will result in internal engine damage.

Water pumps are usually mechanical, but they can also be electric. They keep coolant flowing through your radiator to work correctly and keep your engine at an optimal temperature while driving—but they can wear out over time or fail if they’re not maintained properly.


worn-outSome of the reasons why you could be hearing a whistling noise from your car include a loose or worn belt, dirt in the alternator pulley, worn out tension roller, or a failing water pump. Go through the diagnosis and fixing processes we’ve listed here to get it resolved. I hope this helps you with your car whistling noise problem. Remember to do your research and be safe