Cold start noise.
I just purchased this 2009 Impala and it makes the strangest high pitched winding noise when you first start the car when cold. Its almost sounds like some kind of little jet engine spinning up and once it warms up a little the thing begins to wind down and stop. It doesn't seem to be affecting the performance but it doesn't sound right to me. Can anyone else tell me if this is normal or something I should be concerned about. Dave
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Answers
I'd think of power steering pump, if it has hydraulic power steering still.
An idler pulley on the serpentine belt.
Another possibility might be a vacuum leak that closes some as the engine heats up. It may still be leaking, but the size of the opening and volume has changed so the sound is not created any longer.
2014 Malibu 2LT, 2015 Cruze 2LT,
I wouldn't have thought of the secondary air pump because the air pump on my Cobalt 2008 sounds a little different from that. I has a delay after a cold start of half a minute or so but when it comes on it's more of a pumping sound and it quits after about 30 seconds or so. But I can see it has a vacuum cleaner sound now that
the Cardoc3 posted.
My Cobalt does not run the air pump on a cold start after sitting for short times during a cold winter day, at least not that I notice. But after a long overnight period where the engine coolant inside completely cools to garage temp 40-50 deg F, it does run. Same if it sits outside for hours on cold winter days not being driven after morning coffee until late afternoon or evening to put it in the garage, then I hear it running for 30 seconds or.
Does your car have a voltmeter? I start my Cobalt inside the garage and if I idle for a time, I see the headlights dim briefly and then brighten again when the current load of the secondary air pump kicks in. If your car shows that addition of a load when the sound starts, that might help tell you it's the normal operation of the air pump.
Good luck finding it and I hope it's something normal. Sounds like you have a good car there that will give you service for a long time with little maintenance.
If you determine what it is, please post here again to let me know.
2014 Malibu 2LT, 2015 Cruze 2LT,
2014 Malibu 2LT, 2015 Cruze 2LT,