Recently I started hearing a rattling/grinding metallic sound coming off the right rear while driving slowly. This sound is not reproduced when braking.At first it started while doing sharp right turns only, now its ever present while driving. I showed it to a mechanic he says rotors needs to be replaced. Is he right?
I doubt that anyone here can answer your question.
We cannot see it and you have not given us much information to go by.
When was the last time the rear brakes were replaced?
Grinding would be an indication of overly worn brake pads and if this noise has been there for some time…the rotors are most likely shot.
Once you hear the grinding, it’s time to have the brakes checked…not in two weeks. This way the rotors may have been ok yet.
I thought about worn out pads too, but there is no noise when the brakes are applied. But that would account for replacing the rotors rather than refacing them.
Ok looks like I will have to replace rotors and brakes.
Sounds like brakes but have them check the bearing too.
Besides brakes and bearings, tire wear problems can cause this symptom too. Carefully inspect the tread of that tire to the one on the other side. Notice any differences in the wear patterns? One idea, you could temporarily switch the two rear tires, see if the noise moves to the other side; if so, you’d know it was a tire problem, and not the brakes or bearing.
If your mechanic says the rotors need replacing b/c the rotors are worn out and shot, of course they (and the pads) should be replaced in any event.
Took me a while to find the source of a similar sound on my 07 Accord. I had a rusty heat shield falling off. I took it off and 90% of the noise is gone. Now on bumps I hear a creaking sound and found my right rear stabilizer link the source.
I will add this . . .
I, for one, can distinguish between a heat shield and a cat with a loose monolith
I’m saying this, because I’ve encountered both situations plenty of times
Quite possibly, the mechanic who diagnosed the cat, recognized the distinctive sound of a loose monolith