Diagnosing Noise From the Back of Your Car

The interior of your car is typically sound-proofed to a certain degree, but sometimes annoying noises can be heard while traveling. Noise can be caused by something as minor as loose baggage or as major as a worn-out shock absorber. Some people simply ignore the noise, but neglecting the problem can lead to more damage and might put your life in danger.

Step 1

Park your vehicle in a safe spot to check the noise. Turn off the engine and engage the vehicle's handbrake. Open the trunk of your car and look for loose baggage, or items that might be generating the noise. Transfer the baggage to your rear seats, drive your car, and listen for any more noise.

Step 2

Look at the spare tire at the base of the trunk and check if its holding bolt is loose. Check to see if there are any loose tools. Look at  each compartment inside the trunk and see if there are objects that might be bumping against each other.

Step 3

Look at the strip of rubber insulation attached around the edge of the trunk lead and look for any damage. A damaged or misaligned rubber strip can cause the lead to hit the trunk from time to time and create noise.

Step 4

Have your car elevated with a hydraulic lift in a gasoline station, then look at the muffler under its chassis. Inspect the muffler and look for any damage or missing flanges and bolts. Check for any missing rubber o-rings or rubber brackets that support the muffler in place.

Step 5

Park the car in a safe spot, switch off the engine, and pull the car's handbrake. Repeatedly push down the bumper on one corner of the car and allow the body to rise back up. Listen for any noise while the rear portion of the car is moving up and down. A worn-out shock absorber generates noise while moving. Repeat the same procedure on the other end of the bumper to check the other shock absorber.

Step 6

Lower the rear windows, then listen to determine if the noise is generated each time you step on the brake. Problems in the rear brakes of your car can generate noise each time you step on the brake pedal. A distorted brake shoe, broken brake shoe return springs, or worn-out pads can produce odd sounds coming from the rear portion of your car.

Step 7

Check each rear tire for any damage such as cuts, bumps, sidewall damage, bead damage, or tread damage. Damaged tires cause various sounds that increase in pitch as your vehicle speed increases.

Step 8

Park your car in a safe spot and place tire stoppers in both front wheels to prevent the car from moving. Shift  lift its wheel from the ground. Hold the tire on each side with each hand, then 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. A worn out or loose wheel bearing can create noise.

• AA1 Car: Shock Absorber and Strut Diagnosis
• 2 Car Pros: How Exhaust System Works 
• Just Brakes: FAQ 
• Integrated Publishing: Tire and Wheel-Bearing Noise