I have a 2005 Cadillac CTS with 23k miles. It was my grandmothers car and is in excellent shape. It has had regular service and has had no mechanical problems. I have noticed recently that there is a humming noise that corresponds with the rotation of the tires. It seems to be coming from the left side and is almost unnoticeable at slow speeds but around 55-60 mph it is very noticeable. I had the wheels rotated with the last oil change and it seemed to stay the same, although the left rear tire is now on the left front. That tire loses pressure and I check it weekly. It’s always a few pounds low. Could a bad tire be the cause of the noise? There is no vibration in the steering wheel and it doesn’t get louder when I turn the wheel to one side of the other like a wheelbearing might. Ideas? Thanks!
Have you had that tire inspected to see if there is a screw in it or something that could be causing the slow leak also making the humming noise?
Yes, check that one tire. At a tire shop , take it off and put it on their spin balancer. Slowly spin by hand and look closely. the more eyes the better, looking for tread wobble, something in it, bubbles etc.
– How old are those tires ? Are they the originals ?
Rubber hardens with age and the same tires that were quiet when new may not be now.
I still think that a wheel bearing is a possibility. I had a bad wheel bearing on my 2003 4Runner and it didn’t get louder when I turned the wheel from side to side.
While the Caddy only has 23K on it, whacking a large pothole could indeed damage a wheel bearing. It could also cause internal tire damage.
And I agree with Ken that 9 year old tires with much of the tread worn off can indeed become noisier dut to degradation of the rubber (especially in hot weather) and wearing of the tread.
Find a shop that has a machine that does “road force balancing”. That spins the wheel with simulated road force applied to the tread via a spinning drum. It’ll detect internal defects better than regular spin balancers.
Also, jack up each wheel independantly and spin it by hand. If one makes a whirring noise, that could be a bad bearing. Any experienced tech with a good ear should be able to tell if an unusual noise occurs and what it represents.
If tire rotation was delayed, then a tire or tires can wear oddly so that they make noise. Rotation does not cancel out the noise immediately. Give the tires a few thousand miles to adjust. The noise may or may not go away.
If rotating the tires didn’t change the noise, then it is likely something that didn’t move. I vote for bearings.
It would be helpful if it could be determined if the noise is from the from or the back in addition to being on the left side.
The noise was getting louder and louder, so I ended up replacing the tires and the noise went away. The tires were worn and feathered.
Thanks for all the suggestions!
Right…Most tires get noisier as they wear…Thanks for clearing your thread…Have your alignment checked…
OK, so now this sounds like an alignment problem that was wearing an uneven pattern into the tires.
I suggest you get the alignment checked or you will be experiencing the problem again.
“worn and feathered” . . . sounds like the toe is off