Hi all. I just bought a 1998 escort zx2 with manual transmission. Everything is ok with it. It drives like brand new. Only problem is it produces a loud HUM, like a small cessna airplane kinda noise. I can't pinpoint if it's from the front or rear, left or right, all I know is that it's speed dependent. The noise starts around 35mph and increases in loudness as speed increases, then gradually decreases in loudness from 55mph upwards. It's not the engine because the sound doesn't change if I put the gear in neutral and just coast or if I rev it hard. It's just speed dependent.

The only clue I have is that the noise disappears when I'm turning left. I thought it was the wheel bearings, so I lifted each wheel up and shook each one looking for some play, but they were all tight. The cv joint looked okey, with the boots in good shape.

Any ideas? Can the bearings be bad even though the wheels are tightly held? Please help. Thanks in advance.

It's FIXED! I couldn't wait for your replies. I brought it to Pep Boys and told them to replace the rear wheel bearing which I suspected (the wheel had no play, but I felt/ heard a slight friction/ faint grasping sound when I turn it around, unlike the other 3 wheels which were smooth and quiet. They said they would check the front as well, but they founf out that it really was the rear driver side.

I just got it back and yep, that fixed it! Now I am a smiling new owner of this little car with big potential.