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Humming like a hub bearing

My wife has a 02 sunfire. its making a noise she describes as an airplane noise and i would call a humming (very similar to the one made by 98 grand prix’s bad hub bearing) when turning right the hum becomes quieter almost non-existent. but when turning left it becomes louder. no sign of grease coming from any of the bearings so no luck in determining which was faulty that way. going on advice that ive found several places i determined that it must be the right hub bearing because when you load the faulty bearing it will get louder. i replaced the right front hub bearing. noise still there. so thinking my wife misdiagnosed which end of the vehicle the noise was coming from i replaced the rear right hub bearing. noise still there. i talked to a mechanic who advised that sometimes in this dry climate out here in AZ the rubber boots on the half shaft will get dry and stiff and make a similar noise when turning so i should thoroughly apply some wd-40 to rejuvenate the rubber and see if the noise is gone. noise still there. should i replace hub bearings on the left or should i be looking somewhere else?

Jack up the left side (support it safely) and spin the wheels listening and feeling (e.g. in the springs) for grinding/vibration. This should tell you whether the bearings are a good bet and whether it is front or rear.

The thing is that I would think you were correct to assume the right side. So it is a little weird. If you don’t get any grinding out of the driver’s side wheels the bearings could still be bad, but I’d be hesitant to go there - unless it is reasonably cheap and easy.