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Squealing noise from engine bay on 2017 Impreza

0

Chris P. · rep 0 · May 22, 3:19 AM · 1 replies · solved · Question

Vehicle: 2017 Subaru Impreza Premium

Hey everyone,

I'm looking for some advice on a persistent issue with my 2017 Subaru Impreza Premium. It has about 70,000 miles on it, and for the past few weeks, I've noticed a loud squealing noise coming from the engine bay.

The noise is most prominent on cold starts and tends to get louder when I turn the steering wheel, especially at low speeds. It sounds like it's coming from the front of the engine, near the belts. It sometimes lessens after the car warms up, but it's still noticeable.

Could this be the serpentine belt, or perhaps a pulley? What's the best way to diagnose this at home before I take it to a mechanic? Any specific things I should look for?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:19 AM

0

ClearTheCode admin answer:

A squealing noise from the engine bay, especially on cold starts and when turning the steering wheel, is a classic symptom of an issue with the serpentine belt or one of the accessories it drives. At 70,000 miles, your 2017 Impreza is at an age where these components can start to show wear.

Here's how to diagnose and what to check:

  1. Serpentine Belt Inspection:
    • Visual Check: With the engine off and cool, inspect the entire length of the serpentine belt. Look for cracks, fraying, glazing (a shiny, smooth appearance), or missing ribs. A glazed belt can lose traction and slip, causing squealing.
    • Tension: While you can't easily check tension without a gauge, a very loose belt can also squeal. However, modern Subarus typically use an automatic tensioner.
  2. Accessory Pulleys: The serpentine belt drives several accessories, each with its own pulley. A failing bearing in any of these pulleys can cause a squeal.
    • Power Steering Pump: Since the noise gets louder when turning the wheel, the power steering pump (if hydraulically assisted, though many newer Subarus are electric) or its pulley is a prime suspect. Even with electric power steering, the belt still drives other components.
    • Alternator: Check for any wobble or excessive play in the alternator pulley.
    • A/C Compressor: Listen for noise from the A/C compressor clutch or pulley.
    • Idler Pulley/Tensioner Pulley: These pulleys simply guide the belt or maintain tension. Their bearings can wear out and cause noise.
  3. Diagnosis Steps:
    • Water Test (Caution!): With the engine running and squealing, carefully spray a small amount of water onto the ribbed side of the belt. If the squeal temporarily stops, it strongly indicates a slipping belt. If it doesn't stop, the noise might be coming from a pulley bearing.
    • Stethoscope/Hose: Use an automotive stethoscope (or a long piece of hose held to your ear) to pinpoint the source of the noise by listening near each pulley.

When to see a shop:

  • If the serpentine belt is severely cracked, frayed, or broken – do not drive the car.
  • If you've identified a noisy pulley but aren't comfortable replacing it or the belt yourself.
  • If the noise persists after replacing the belt and you can't pinpoint the source, as it could indicate a more complex issue with an accessory component.
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