What are the symptoms of a bad alternator pulley?

[MacElizabeth]

When the alternator pulley fails, it will cause abrupt acceleration/deceleration without cushioning effect, produce abnormal noises during startup, and make rattling sounds even with light throttle input. If these symptoms occur, please immediately visit a 4S shop for inspection, repair or replacement. Below are maintenance measures for automotive alternators: 1. Monitor bearing wear: If insufficient lubrication is found, add a few drops of engine oil through the oil cup opening, being careful not to let it seep into the rectifier as this would affect electrical transmission. 2. For uneven brush contact surfaces: Smooth them with fine sandpaper. Replace brushes when spring elasticity is insufficient or brushes are excessively worn. For undamaged but overly short brushes: Insert shims into the holder to ensure proper contact with the rectifier. 3. Keep the alternator's dust cover secure: Never remove it as this prevents dust ingress that could cause mechanical failures.

[VanFrank]

When the alternator pulley on my car failed recently, it was a nightmare. After starting the engine, there was constant squeaking noise, especially when accelerating - it turned into high-pitched screeching like metal scraping. While driving, the headlights flickered, the AC stopped blowing cold air, and the battery warning light on the dashboard stayed on. If neglected, a completely failed pulley could cause belt slippage or breakage, leading to sudden engine stall or even overheating damage. That expensive repair taught me a lesson: regularly check belt tension and look for cracks/wear to prevent minor issues from becoming major disasters. Now I inspect the belt condition every six months - safety first.

[DelPhoebe]

Suddenly while driving, I noticed an issue with the electrical system: the battery warning light on the dashboard kept flashing, the headlights dimmed like a dying flashlight, and even the AC stopped blowing cold air. The mechanic later diagnosed it as a faulty alternator pulley—the belt couldn't turn, cutting off power to the system. Key symptoms included this electrical instability plus grinding noises from the engine bay, like a rusty chain turning. Continuing to drive risks severe battery drain, leaving you stranded with a dead starter. Don’t delay repairs too long, or the belt could snap and jam into the engine, making tow-and-repair costs even steeper.

[GeorgeFitz]

Symptoms of a bad alternator pulley are quite noticeable. Initially, there's a humming noise from the engine area, which turns into a sharp screeching sound during acceleration due to belt slippage. Sometimes, you may feel abnormal vibrations while driving, with lights and music flickering. A faulty pulley can also trigger engine overheating warnings or cause the AC to fail. A simple check involves inspecting the belt for looseness or cracks. Replacing it promptly will prevent further issues.