* Power Steering Pump: This is a very common cause of whining noises, especially when the engine speed increases (like when you accelerate). A failing power steering pump often makes a high-pitched whine that gets louder with increased steering input and engine RPM.
* Alternator: A failing alternator can also produce a whining sound, often described as a high-pitched squeal or whine. This is more likely to be constant, but the load on the alternator increases when accelerating, potentially making the whine more noticeable.
* Belt Tensioner or Idler Pulley: These components guide and tension the serpentine belt that drives several accessories (alternator, power steering pump, etc.). A worn or failing tensioner or pulley can make a whining noise, especially when the belt is under increased stress during acceleration.
* Wheel Bearings: While less likely to be directly related to acceleration, a bad wheel bearing can create a whining sound that changes pitch with speed. This might be more pronounced when accelerating because the wheel speed increases.
* Transmission: In some cases, a problem with the transmission, such as low fluid or internal wear, can cause a whining sound, particularly under acceleration. This is less common than the other possibilities.
* Differential: Similar to the transmission, a problem with the differential can create a whining sound, particularly under load (acceleration).
To diagnose the problem:
* Listen carefully: Try to pinpoint the location of the sound. Is it coming from the front, rear, or under the hood? Does the pitch change with engine speed or steering input?
* Check fluid levels: Check your power steering fluid and transmission fluid levels. Low fluid can exacerbate existing problems.
* Inspect belts and pulleys: Look for cracks, fraying, or other signs of wear on the serpentine belt and pulleys. Listen closely to the area around the pulleys while the engine is running.
* Have a professional diagnose: If you can't identify the cause, it's best to take your Cobalt to a mechanic for a proper diagnosis. They have the tools and expertise to pinpoint the problem accurately and safely.
Ignoring a whining noise can lead to more significant and expensive repairs down the road. Addressing it promptly is recommended.
