2006 Acura RL has metallic hissing sound coming from wheels at highway speeds?

I have a 2006 Acura RL that I purchased as a certified used car from the local Acura dealership about 5k miles ago. It currently has 51k miles on it and about 3-4k miles ago a sound started emitting from (to the best of my knowledge) the wheels.

The sound only occurs after 5-10 minutes of driving (enough to get things warmed up) and when driving over ~35mph. The noise gets progressively louder with higher speeds until it seems to plateau (though, I never go over ~65mph, so this is a little hard for me to confirm).

The sound emitted is a metallic hissing sound. I actually took it into the Acura dealership last week regarding the sound. They resurfaced the rotors since they said they were glazed (they did this free of charge since this had also been done when I bought the car and they said it shouldn’t have needed it again so soon). They checked the brakes (the dealership also replaced the front brakes when I bought the car).

After leaving the dealership and driving home, I noticed that the sound was still being emitted, but was a fainter and higher pitched sound now. It is definitely not as loud as it was before and the tone has changed.

The sound is highly annoying, particularly when driving down a rural road with dense trees or an embankment on either side since the sound seems to bounce off. I haven’t been able to determine where the sound is coming from exactly…it appears that it is from all over, though granted I never ride as a passenger in this car.

The car is still under warranty (until October anyway) due to it being a certified used.

I would simply go back. It could be as easy as a wheel bearing. However your vehicle has a complex AWD system too that may have some issues. Very hard to diagnose from afar. Maybe visit an Acura forum and see if a common issue?

I actually posted the issue to an Acura specific forum (AcuraZine) a week ago, but unfortunately they’re stumped too, other than a possible wheel bearing.

It can sometimes be hard to get an answer out of Acurazine. What if it’s a dust shield scraping on the rotor? That’s where I’d start looking.

I just spoke with the service manager and made another appointment for later this week. He’s going to have a tech ride with me so the sound can be heard. Hopefully this will get resolved after this visit. I’ll post my findings!

Took a ride with the lead tech and then took another ride with the tech who resurfaced the rotors the previous week…neither could hear the sound. My wife and brother can hear it, but obviously it would be much more helpful if someone who could actually fix it could hear it.

I did record it on my iPhone, though it is faint on the recording. I’m going to see if I can amplify it enough and post it on here.