Hyundai Elantra makes an intermittent high pitched squealing noise at highway speeds

My girlfriend’s Elantra (mid 90s model, I think) makes an intermittent noise when on the highway. It sounds to me like it could either be from friction or some sort of wind noise, but I suspect it’s the former. It only seems to happen at speeds above 50 or so. When it occurs, it is always the same pitch and loudness – these don’t seem to vary. It’s rather loud, to the point where it is pretty unpleasant to drive when this is going on. It has happened both when my foot is on and off the gas pedal. When the noise happens, it can last anywhere from just a second to up to a minute or more. I haven’t been able to identify anything obvious that it’s correlated with – wind direction, grade of road, etc. The only thing I do know is that it only seems to happen at highway speeds. We never hear it during city driving.

So far one mechanic has confidently misdiagnosed the problem as a bad wheel bearing. Any thoughts on what could be going would be much appreciated!

Probably wind noise. Try taping around top and sides of windshield with 2" wide masking tape as a temporary test. Also tape up door gaps to test.

Correction: it’s a 2003

The diagnosis of a bad wheel bearing wouldn’t be out of line. Usually they make more of a growling noise, but a whining noise is possible too. Don’t diss the mechanic too much for saying that as the possible culprit. If all else fails and you don’t get any results, there’s a gadget some shops own where they connect a bunch of microphones to various places on the car, then drive it, and listen to each microphone to see where the noise is originating.