My 2013 Acura TL 2WD (153k mi) has developed a noise that sounds like a small electric motor near the left front wheel. The noise becomes apparent at around 30mph and increases in frequency as the vehicle speed increases. I’ve measured the frequency at about 250Hz at 30mph up to about 500Hz at 40mph. In park, I can rev the engine and not hear the sound; if I’m going downhill and shift into neutral, there’s no change to the sound. The noise started to become audible about a year ago (around the time I replaced the alternator - not sure if it was before or after, but the alternator is on the right side and the sound is definitely on the left) and has persisted through two different sets of all-season tires and a set of winter tires (on different rims). I replaced the front pads and rotors this weekend - the noise may be a bit quieter now but persists; during the change out I did not observe any obvious physical cause for the noise. Any suggestions are most welcome - I’m stumped!
Check for a worn wheel bearing.
Raise the vehicle so that tire is off the ground. Grab the tire at the 12 & 6 O:clock positions and see if you can wiggle the tire. If you can it means that wheel bearing is failing.
Tester
Does the noise change at all when you turn the steering wheel?
I’ll second the wheel bearing idea.
While you have the wheel off the ground doing Testers check, spin the tire while touching the coil spring in the strut, if it has a vibration to the spring, then replace the wheel bearing…
But you should get three different noise levels while driving, one while going straight, one while veering left (like in a curve) and one while veering right (like in a curve), if the noise get louder while veering (slightly) right, your loading the bearing, if it makes less noise while veering left (again slightly/in a curve) then you are loading the right bearing and less load on the left bearing and not making as much noise…
So a left front bearing gets louder veering right when bad…
It is a 2 row bearing and can make noise without being loose (typical inner row), or it can be loose without making noise (typical outer row), it is when it is loose and making noise that it is about to fall off…
Does the noise increase or decrease if you make turns, change lanes, etc.?
If you had a stud replaced on that wheel (IIRC, your supposed to separate the hub a little) or the axle replaced on the left front, the axle nut may not have been torqued to spec and is loose causing the bearing to degrade also…
Not in any appreciable way.
I’ll third the wheel bearing.
Thanks to everyone for the diagnosis! My mechanic will take a look next week - this appears to be a bigger project than I’m inclined to tackle on my own.
Don’t tell him that us smart guys on the internet told you it’s a front wheel bearing. We haven’t actually seen and drove the car.
He’s a top-notch mechanic - he’ll do the right thing!