Mechanics

Popping

If your car is creating a popping noise it means a component has failed or is failing, there is no "normal" popping noise. There are several systems that can make a popping noise such as a heater blend door actuator. Popping can also be generated from a suspension component such as a sway bar link that has become worn and has excessive clearance. These popping sounds can be created either when the car is moving or standing still depending on the system that is generating the noise. Sometimes just turning the ignition key to the on position can begin the popping sound and occasionally a car can pop just sitting in one place. Other pop sounds are created when a system is engaged and then stops when the system is switched off such as an air conditioner system. While still other popping noise are created when the car is driven in certain conditions such as a bumpy road or at a particular speed. We have list common problems below:

Popping Noise
Popping Noise

Car Repair Guide

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 can 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 failed shock or strut with a new unit.

Front Strut Leakage
Front Strut Leakage

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, re-tighten or replace as needed.

Checking Drive Axles - Front wheel drive cars utilize front drive axles with CV (constant velocity) joints. When CV joints start to wear they will bind up on acceleration, especially in a turn. This causes a popping sound in the front suspension that transfers to the vehicle. Remove drive axles and inspect flexibility of each CV joint. If a bind or hard spot is observed the CV Joint-Axle needs to be replaced.

Front Wheel Drive Axle
Front Wheel Drive Axle

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 ticking 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 manual is needed for exact procedures, every car is different (note: car realignment is required when replacing suspension components)

Check Engine for Over Heating - Engine coolant is used to transfer heat from the engine to the radiator; if a coolant leak is present the engine will eventually overheat. When a engine is overheating it can create a popping noise. Never check the coolant level when a engine is hot. Always check the coolant level when the engine is cold, preferably over night. After the engine has cooled off inspect the engine coolant level in the coolant reservoir tank; coolant level should be between the hot and cold marks. If the coolant level is not between the reservoir marks the cooling system may have a leak.

Radiator Cap and Coolant Reservoir
Radiator Cap and Coolant Reservoir

Check Engine Thermostat. An engine thermostat is designed to regulate the flow of coolant from the engine to the radiator. This temperature sensitive valve is designed to open when the engine has reached operating temperature (190°-198° F). When a thermostat fails it will either stop the coolant flow "stick closed" causing the engine to overheat. When this condition occurs the engine will create a popping or thumping noise as the engine coolant boils. To check for this condition allow the engine to cool completely and follow this link: Testing an engine thermostat

Engine Thermostat
Engine Thermostat

Checking Tire Lug Nuts - The rim and tire of your car is designed to hold extreme pressures of normal usage. If the rim has developed a crack or if the lug nuts that hold the rim to the wheel hub are loose it could create a popping, rattling or clicking noise. To check for this condition remove the wheel cover (if equipped) and inspect the rim for cracks and check the tightness of the rim lug nuts, If a crack is observed replace the rim immediately and tighten all lug nuts to specification.

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 suspension noises when they are worn out or need lubrication. 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 popping noise when the car is exiting or entering or driveway, or any condition that twists the car in an unusual way. The popping noise is generated when the body to forced away from the frame. 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 a 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 new and recheck.

Frame/Body Bushing Assembly
Frame/Body Bushing Assembly

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.


COMMENTS TO THIS ARTICLE


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.



Article first published (Updated 2014-03-08)