Mechanics

Rattle

Car Moving:

This section includes symptoms that present themselves when the car is in motion

Inspect Shocks or Struts - The strut or shock in your car is designed to dampen unwanted vehicle motion. If these components become loose or leak they came create popping, banging and rattling noises. To check for this condition inspect the mounting bushings and connecting bolts making sure they are tight and in good condition. Also inspect the shocks or struts for leaks, if oil is detected replace the component with a new unit.

Front Strut Leakage
Front Strut Leakage

Loose Brake Caliper or Brake Pads - The brake pads and calipers are designed to slow the vehicle when applied. The brake caliper hold these brake pads that are applied to the brake rotor. If the caliper is loose or if the brake pads are not fitted properly they will make a clicking noise. To check for this condition inspect the brake caliper mounting bolts and brake pad mounting. The brake pads should not move vertically. If so the brake pad shims could have fallen out or the wrong brake pads are installed.

Checking for Engine Ping - When a engine pings the combustion processes inside the engine has been altered in the respect to the control of the rate of the explosion inside the combustion chamber. As a ping occurs an audible rattling sound is created as the combustion process is more like a flash instead of a controlled burn. Most car engine are equipped with a knock sensor which controls this condition. But if the fuel the engine is using octane level is way is too low it can cause the engine to ping anyway. Try using a higher octane level fuel, if the engine continues to ping try replacing a knock sensor even though the check engine light is not illuminated. If the problem persists the engine could have excessive carbon build up and a de-carbonization service is needed.

Check Sway Bar Mounts - The sway bar or bars, (some cars have front and rear sway bars) on your car are designed to prevent the car from rolling (leaning) when cornering. These sway bars are mounted to the frame and connected to the suspension arms using connecting links. If either the sway bar mount or the connecting links becomes worn or lose it will generate a banging, popping or rattling sound. To check for this condition check the mounting bolts and bushings, retighten or replace as needed.

Inspecting Tie Rods - The tie rods connect the steering to the spindle which is attached to the rim and tire. These tie rod ends have a ball joint at one end and threads on the other. When the universal or ball joint wears it can cause popping or rattling sounds. Check the tie rod end for wear and replace as needed. (note: car realignment is required when replacing suspension components)

Checking Control Arm Bushings - The control arm bushes are designed to allow the suspension arms to pivot near the frame mount. These bushings are constructed of two metal collars, one large and one small with rubber molded inside the larger collar holding the smaller collar inside. Control arm bushings help prevent road vibration from being transferred to the car frame. With time and usage the rubber inside the bushings can deteriorate allowing the suspension arm to rattle and make bumping sounds. To check for this condition use a flashlight to view the upper and lower control arm bushings. If any rubber is missing or pushed out of the side of the bushing it must be replaced. Control arm bushings are sometimes serviced by replacing the whole suspension arm. To replace the suspension arms or bushings a car repair manuals needed for exact procedures, every car is different (note: car realignment is required when replacing suspension components)

Inspecting Ball Joints - The ball joints in your car's suspension are used as the universal joint that allows the movement needed in a suspension system. This joint is constructed of a metal base in the form of a pocket and the ball which fits inside the pocket. Both parts are made of metal and require grease to work freely. These joints are under extreme pressure and can cause rattling noises when they are worn out. Ball joints can be difficult to replace, we suggest using a car repair manual for the exact car repair procedure. (Note: car realignment is required when replacing suspension components)

Checking Frame Bushings - Your car is equipped with bushings that separate the car frame from the body. These bushings are constructed as a rubber donut with metal a retainer one side. The bushing is held in place by a main through bolt. Some vehicles are constructed with a "full frame" this means the frame runs the full length of the car. While still other cars are designed this two separate frame members, a front and rear frame member. This style of car framework is called a uni-body. If a frame bushing becomes lose or has become dilapidated it can cause a rattling noise when the car is driven over bumps. To inspect for this condition raise the car high enough to get a clear view of all body/frame bushings. Next, use a flashlight to visualize all body bushings, look for rubber that has separated or is missing. Also, if rust colored powered exists around the bushing, this is evident of excess movement the bushing. If any of these conditions exist replace the body/frame bushing with a new unit and recheck.

Frame Body Bushing Assembly
Frame-Body Bushing Assembly

If further assistance is needed, our certified car repair technicians are ready to answer your car questions.

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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-08-16)