09 Impala, Whining Noise Coming from Under Hood

So I have a 2008 Chevy Impala LS that hasn’t given me any real problems. I had some battery troubles recently that were the result of me leaving the parking/security lights on for 10 consecutive hours, but overnight-charged the battery and was good-to-go after that. But it seems like RIGHT after that was when the whining noise started.

It seems to be related to my power-steering system. I know this since the whining seems to pick up with acceleration and turning. However, I checked my power steering fluid and it did not appear to be depleted at all. I did notice, however, that it seems to be a light greenish color…which from doing a google search, I’ve gotten the impression that it’s probably not supposed to be that color.

What exactly is going on here?

I’d have the alternator checked out. They often whine when starting to fail. If your car was run when the battery was very low, the extra load on the alternator might have damaged it.

Light greenish sounds like radiator fluid. Usually its pinkish. I would make sure you’re checkinf the ps fluid. It has a screw off cap with a little dipstick attached to the cap.

Power steering noises would get worse when turning the steering wheel, not so much b/c of acceleration. But since you do notice an association with turning the steering wheel, it could be that. I’ve never noticed a green color to any of my power steering fluids, but maybe that’s just the color the tech who did the last refill used. There’s no route for the engine coolant to get into the power steering fluid (other than someone servicing the car accidentally doing that).

First thing is to get out your owner’s manual and check the power steering fluid, following those directions. If it seems ok, neither under nor over-filled, and the fluid is clear for the most part, not completely dark and opaque, then the next step would be to use a mechanics stethoscope to see if the noise is more likely coming from the power steering pump or the alternator. Or neither.

Alternators definitely will make a whining noise sometimes when the battery is overly discharged. But it should go away pretty much after driving a few dozen miles on the freeway. If it doesn’t, that could be a bad alternator or a battery on the fritz that needs replacing. Ask a shop to do a “load test” on the battery to decide.

I’ve had the alternator start to wine if a diode went out. Soon after that the battery discharged and confirmed it. An old timer told me that was typical of a failed diode to make noise. Have your alternator checked out. Places like AutoZone or Advance Auto Parts will test them free.