unexplainable noise
 

I have a 2001 Saturn sl2 I have a high pitch noise coming from the front some where the noise only starts at 45 mph and stops about 55-60 mph this happens when I am driving straight, turning, accelerating and decelerating. I am not sure what it would be. I have a hard time believing wheel bearing since its not only when I turn. the trans fluid is good color and full. I was thinking maybe cv axle??? I would like to figure out something before it breaks and leaves me stranded. I was thinking about doing both cv axles and both wheel bearings at the same time just because if I have to remove one or the other they are so close together that I don't want to have to re-remove everything just to do the other if one of them didn't fix the issue. any other ideas before I do that would be greatly appreciated. thank you.

Assuming this is an A/T. I would think at that speed it may be the low end of the highest gear. Have you tried safely forcing a downshift while going 45 and seeing.if the noise is still there at the same.speed but in a different gear.

If it is truly a squealing noise, it could.be the bearings on one.of the pulleys. Remove the serp belt and work each one by hand.

Also, there is an air flow optimizer which feeds into the air box. Yours may be loose and literally whistling. In fact i would remove yours for.the sake of testing.

I'm not sure how you mean to downshift while going 45 but I know the noise starts at 45 then shifts at about 50 and the noise is still there after it shifts ill check the pullys it would be nice if it is one of those because the noise seems to be getting worse as the days go by I got in it today to come to work and at about 50 it is really loud and tapers off as I get to 60. the air flow optimizer is that a port or a sensor that I need to remove? thank you for other options to try it is much appriciated

It is a plastic pseudo rectangular shaped hollow chamber which, I believe, is up against and right behind top front cross member near the hood latch. You can simply wiggle it off the ducting.

As for my shifting question, I was trying to see if the pitch of the noise changed while driving the same speed at different rpms, therefore different gears.

If the pitch IS dependent on rpm, then the pulleys or belt might be in play. IF NOT rpm dependent, likely not the cause.

Just had a thought. Check to see if the spring mounted air dam under the radiator is still connected by both springs and that the bottom tilts slightly forward. If this thing is not seated correctly in theory there could be air slipping through a small slot that isn't supposed to be there

ok thank you so much for your input on my next day off from work I will be sure to check out all of those ideas. thank you again.

so an update. I looked at all the pullys and they were good. I checked my air intake system and that was all good the brackets for the radiator are good I have wheel bearings on order and will be here at the end of the month. I hope that fixes the problem. that's the closest thing that it sounds like just when I'm driving straight. thank you derf for your help.

I have doubts about the wheel bearings being the cause of the noise.

When front wheel bearings start to go bad, you usually hear a low pitch rumbling jet airplane engine sound as you pull away from a stop, and the noise gets louder and louder as you increase in speed.

Also, the noise of failing front wheel bearings will greatly increase in volume when you turn in the direction that shifts the car's momentum its direction. Meaning if you are driving and turn the steering wheel to the right, this shifts the momentum of the vehicle to the left front. If the left front wheel bearing is failing, the "roar" will greatly increase. The vehicle would be expected to be quietest when it is driving straight.

The type of bearing used in pulleys is usually not of the same design, as the wheel bearing must also withstand the force applied perpendicular to the direction of rotation (the forces described above). Pulley bearings don't need that characteristic.