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Car Noises /
Popping Noise
Car is Making a Popping or Pop Noise
Introduction
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 curtain conditions such as a
bumpy road or at a particular speed. We have list common problems below:
Popping Noise
Car Repair Guide - READ COMPLETELY BEFORE BEGINNING!
- 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
- 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.
- 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
- 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. -
Engine Coolant
Leaks
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 -
How to check a 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 ticking
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
-
Popping Noise When Air Conditioner is On - The
air
conditioner is designed to run with a measured amount of refrigerant and
compressor oil. When the air conditioner is switch on the compressor engages
developing system pressure. If the system has malfunctioned such as a plugged
expansion block or orifice tube it can cause the pressure to exceed normal
limits. When these limits are reached a pressure safety valve will release
causing a popping noise. This condition can also occur if the system refrigerant
limits have been exceeded (too much refrigerant). Once this condition has
occurred the system pressure safety valve will need to be inspected for leaks.
-
Popping Noise From Engine When Accelerating - A
camshaft is commonly used to operate poppet valves in a
piston engine.
A cylindrical rod is situated in
the cylinder block or cylinder head that has oblong lobes or cams which push
open the intake and exhaust valves. This force is applied on the valve
directly or through an intermediate mechanism such as a rocker arm, lifter
(cam follower) and push rods that are used to press against the valve for
movement. Each valve utilizes a spring that will return the valve to its
original position (closed) after the force is removed. If a valve spring has
broken or a cam lobe is worn down it will cause the engine to create a
popping sound. To test for this condition, remove the
ignition coil connector,
ignition system or
fuel pump fuse to disable power
to the ignition or fuel system. Remove the valve covers to gain access to visually
inspect the valve train. Have a helper crank the engine
over while you watch the rocker arms or cam lobes, make sure they are all
going up and down the same amount, if one or more lobes are traveling less
than the others you might have a flattened cam lob and the camshaft needs to
be replaced or a hydraulic lifter/follower (where applicable) that has
collapsed and will need to be replaced. Also inspect the condition of
the valve springs, use a flashlight and small mirror to aid in the inspection
if needed. If a broken valve spring is discovered it will need to be replaced
to correct the problem. And the final check, look at the height of the valve
springs and retainers when in the closed position (pressure off) they should
be exactly the same height. If one valve is higher or lower something is wrong
with the cylinder head, valve or valve seat and needs to be repaired.
Typical Camshaft Configuration
-
Check the Drive Belt Tensioner - A drive belt tension hold a
even amount of tension on the engine drive belt. If this tensioner fails it can
leave the drive belt loose creating a loud popping or snapping noise as the belt
fails to grip the pulleys and then regains grip. Check the tension, if weak
replace the tensioner with new. If the tensioner is ok check the belt size. If
the wrong belt has been installed it will not allow the tensioner to work
properly.
For exact specific repair procedures for any of the steps above visit our
car repair
manuals page.
Car Noises /
Popping Noise
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