Why Does the Serpentine Belt Squeal/Chirp?
The serpentine belt drives the alternator, power-steering pump and AC. Its squeal is common, with causes from simple (tension) to needing replacement.
Causes of squeal
A worn/cracked or glazed belt, wrong tension (a weak tensioner), a worn pulley/bearing, or water/oil reaching the belt.
When it is dangerous
If the belt snaps, several systems stop at once (charging, steering, cooling) and the engine can overheat. A constant squeal with vibration deserves a quick check.
The fix
Inspect the belt visually (cracks/wear), the tensioner and pulleys. Replace a cracked belt and do not delay. A morning damp squeal alone may be transient.
FAQ
Squeal at start then gone?
Usually moisture or temporary tension; monitor it. If it recurs or grows, check the belt and tensioner.
Can I drive with belt squeal?
A short distance yes, but do not delay the check — a snapped belt stops charging and cooling suddenly.