[Juan123]

Hello. I have a 2008 Mazda 3 Sedan, and for the past month or so, I've been hearing a "flat tire" sound coming from the passenger rear area. As a new Mazda owner, I'm wondering if anybody else has had a similar issue? I've so far had new tires put on about a month ago, and rear struts/shocks put on about 6 months back. I don't know if that maybe playing affect?

 

[RocketmanKarl]

"Flat Tire" sound is a little vague. Going to need more description of the noise, is it speed related, and any conditions under which it comes and goes.

Did the noise start before the new tires, at the same time, or after the new tires? Are they a stock tire size and are the rims factory or aftermarket?

Without more information, it's hard to guess what's going on, but here goes:

• Loose trim or guards. There are several plastic panels under the car, in the wheel-well, or attached to the rear bumper. If one of those is loose, it could make a flap-flap-flap kind of noise. Jack up the car, put a jack stand under the car, and feel around for any loose parts that might flap in the wind.
• Wheel bearing or suspension. A bad bearing can make a roaring sound, but it can also make an oscillating sound. It can also be hard to hear/feel when the car is up on jacks. But while the car is jacked up to look for loose plastics, spin the wheel, and wiggle it in and out to see if the bearing feels noisy or loose, or if the suspension bushings are shot. If you need one to compare it to, jack up the other rear corner and see how that one feels.

 

[Milanomike]

What "RocketmanKarl" said, but since you have new tires (assume correctly balanced), new shocks back there, guessing you might be hearing a wheel bearing noise. Can be a growl or woo woo type noise. Should be relatively easy for a shop to diagnose. If DIY, i'd lift up rear, remove brake pads, put wheel on and spin and feel for looseness and listen for noise.