I have 1997 Chevrolet Lumina sedan. I’m trying to diagnose a sound coming from my engine. It is a “whirring” noise that varies with the engine speed (e.g., if I accelerate, the sound becomes louder and the pitch increases a bit). The sound occurs constantly, but is best noticed during acceleration.
About 8 months ago, I heard similar noises and it turned out to be the alternator since the battery was draining and the voltage was below acceptable levels. Had that replaced and the sound went away.
I’ve opened the hood while the car is running, and the sound is definitely in the region of the alternator. However, I also know that an idler pulley with bad bearings can make a similar noise and so too can the power steering system. The power steering fluid is fine; I triple-checked that.
I haven’t noticed any faltering in the electrical system. The interior light doesn’t flicker or vary in brightness with acceleration, the air fan speed doesn’t vary in and out of acceleration, the console lights are fine, and there’s no battery or “Volts” indicator on the console. I’ve tried turning on all the accessories of the car — headlights with brights on, radio, holding the brakes, interior lights on — to see if an indicator would come on, and nothing.
The noise has only been around for a few hours and it’s only been day time so I haven’t been able to try the headlight trick effectively. Also, it is extremely cold: only about 5 degrees Fahrenheit.
Any thoughts on what it could be?