Car interiors are soundproofed to a certain degree, so you can enjoy a comfortable and quiet ride inside your car. But, sometimes annoying or persistent noises coming from outside your car can interrupt that quiet while traveling. Noise can be generated by something as minor as loose baggage or as major as a worn-out shock absorber. Dismissing the issue can lead to more damage and might put your life in danger.
Park your vehicle in a safe spot. If you are driving, find a place where you can safely park to check the noise. Turn off the engine and engage its handbrake to ensure that your vehicle will not move. Pop the trunk of your car and look for any loose baggage that might be causing the noise. Remove any baggage or transfer the baggage to your rear seats, drive your car, and listen for any continuing noise.2
Remove the matting or cover on top of the spare tire at the bottom of the trunk. Observe the tire and check if its holding bolt is loose. Check any tools to see if they are loose. Check each compartment and see if there are objects that might be bumping against each other and creating the noise.3
Look at the strip of rubber that goes around the edge of the trunk lead and inspect it for any damage. If the rubber seal is damaged or misaligned, the trunk lead can hit the trunk from time to time and create noise.4
Take the vehicle to a gasoline station equipped with a hydraulic car lift, and have the car elevated so you can look under its chassis. Look at the muffler and inspect it for any holes caused by corrosion. Observe the flanges where the various sections of the exhaust system are bolted together and check for holes or missing bolts. Check for any missing rubber o-rings or rubber brackets that hold the muffler in place.5
Park the car, turn off the engine, and engage the handbrake. Ask someone to bounce the rear of the car by pushing down the bumper or fender on one corner of the car and allowing the body to rise back up. Perform this procedure several times while listening closely for any noise. A moving vehicle with a defective or worn-out shock absorber can produce noise while moving.6
Open the rear windows, listen to the noise, and determine if the noise has anything to do with your stepping on the brakes. Mechanical problems in the rear brakes of your car such as distorted brake shoes, a bent backing plate, broken brake shoe return springs, or worn-out pads can produce odd sounds coming from the wheel of your car when you step on the brake pedal.7
Inspect both rear tires visually and look for any sign of damage such as cuts and bumps that may be indicative of sidewall damage, bead damage, or tread damage. A damaged tire can produce various sounds that tend to increase in pitch as your vehicle increases speed.8
Park your car and secure it using tire stoppers on the front wheels. Shift the gear to neutral and jack up the rear of the car on one side to lift its wheel from the ground. Wiggle the tire back and forth to sense bearing looseness. Spin the tire slowly by hand and feel it for bearing roughness. Repeat the same procedure on the other rear tire.