2008 Chevy Impala, vibrations and funny sound from hood

I’ve owned a 2008 Chevy Impala for about 7 months. It’s at about 115,000 miles. It runs great…haven’t had any problems out of it. So far. But there are a few things that concern me.

When I start the car, I hear this squeaking noise under the hood. I do not always hear this—it seems as if it may be tied with cold weather, like it’s something that only occurs in the morning. But regardless, it seems abnormal. It subsides after a few minutes. The other thing I am noticing is that normally within the first 10 or 15 minutes of operation, if the car is at a stop light I’ll hear some strange humming accompanied by vibrations. Sometimes the lights will flash faintly when this happens.

When I first purchased the car, I had a mechanic check it out. The engine, transmission, radiator, etc. were in excellent condition. I’m hoping that this is not anything serious, but I figure these are still sounds that I should not be hearing with a car in good condition. Any advice would be greatly appreciated.

The first things that your mechanic should focus on are the serpentine belt (which drives the alternator and other accessories) and the tensioners that are used to maintain proper tension in that belt. The noise & the symptoms are consistent with belt slippage, but whether the problem is the belt, the tensioners, or both, is impossible to determine from a distance.

Agreeing With VDCdriver, On This Unit, It’s Fairly Easy To Pop The Serpentine Belt Off. Once Removed, The Mechanic Should Be Able To Inspect the belt And Also Determine If There’s A Failed Bearing Or Component That Is Belt Driven.

Anyhow, at this age and miles the serpentine belt is due for replacement and that can be accomplished at the same time.

Planning on a way to let the mechanic experience the actual symptoms that you describe would be helpful. Possibly leaving the vehicle outside overnight at the shop would work.

However, I would guess that a good technician can get right to the problem in minutes, cold, warm, or otherwise.


I bought a nearly new rental 2009 Impala, with about 10000 miles, from a Chevy dealership. I returned the car within a few days and complained about the same noise just as you described. They told me not to worry about it, that it is common in these vehicles. I was skeptical about there statement but I now have 54000 miles on it and have not had any trouble. I’m not suggesting that you should dismiss the symptoms, just saying what I experienced. I have not experienced the “humming accompanied by vibrations” you mentioned.

It was indeed the serpentine belt. My 09 Impala is also a former rental, just with slightly more mileage than yours. It’s been an excellent car.


Thanks for the update

What brand belt did you install?

I’ve usually had the best luck with factory belts

As for aftermarket, I generally prefer Gates

I have a 2010 Impala w 60K miles, with a start-up issue of some sort. When the engine is started cold, it runs roughly, sputters, and dies the first several times, as if the fuel/air mixture is too lean. After several tries, it takes off and runs and idles like it should. It starts and runs fine when warmed up. All of this came on suddenly, as opposed to a gradually developing over time. The check engine light is on, naturally, however that was the case long before this starting issue surfaced, and my Chevy dealer has been unable to make it disappear for more than a day or two, so I quit going back there at $90/hr. An ideas on where to look in regards to diagnosing and solving this cold start-up? Could it be a poor electrical connection? Failed component, like a solenoid? THANKS!