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Car Noises /
Rattling Noise
Car is Making a Rattling or Rattle Sound
Introduction
A rattle or rattling noise can be one of the most frustrating sounds to find
and repair. Rattling sound can be generated by almost any part of the car from
the engine to the transmission. The cost associated to repair a rattle can vary
between tightening a lose bolt to replacing the transmission. Like with any
noise, the first step is locating the region in which the sound is be generated from.
A rattle can be generated when the car is in motion or when the engine is
running with the car stopped. If a rattle is consistent with the engine speed it
could be generated by an engine accessory like an
alternator.
If the rattle sound is related to vehicle speed the noise can be generated by a
suspension component like a sway bar link. Interior rattles can be difficult to
determine when the noise is coming from the internal workings of the dashboard.
Other rattle sounds can be created when a system is engaged and then stops again
when the system is switched off such as an air conditioner. Below, there are two
separate sections the first section includes "engine running, car not moving" and
the other section features the "car moving" section. We have list common
problems below:
Rattling Noise
Car Repair Guide - READ COMPLETELY BEFORE BEGINNING!
Engine Running, Car Not Moving: This section includes
symptoms that present themselves when the engine is running only.
- Checking Engine Oil: Your
engine
relies on
engine
oil to supply lubrication the inner moving parts of the engine. If
this oil level is allowed to become insufficient (low
oil level) the engine cam followers or lifters will lose pressure
allowing excessive
clearance in the valve train causing a rattling noise. Also as engine oil
levels further degrade the engine rod, piston and crankshaft bearing can
become damaged allowing clearance producing a rattling sound.
Check the engine oil level and add oil as needed to obtain the proper
engine oil level. (Note: If the engine oil level is low and your engine is
rattling even after you have added oil permanent damage could have occurred
and repair or replacement is required)
- Inspecting the Catalytic Converter: Since 1976 all cars
have been equipped with a
catalytic converter
which helps burn unused fuel from the exhaust system. This device has been
instrumental in air quality improvement. When a catalytic converter fails
the ceramic martial inside the converter will shatter into small pieces. If
this condition occurs it will create a rattling sound when the engine
running in the exhaust system. To check for this condition shut the engine
off, using a rubber mallet give the catalytic converter is small rap and
listen for a rattling noise. If the catalytic converter rattles it has
failed internally and replacement is required.
- Check Engine Accessory Mounting/Condition: When your
engine starts it provides power to various accessories such as the
water
pump, power steering,
air conditioner,
alternator and air pimp (if equipped)
These accessories are held in place by mounting brackets and hardware. If
the mounting bolts become lose or have broken it will create a rattling
noise. To check for this condition inspect the mounting bolt condition in
the area in which the sound is being generated. Also check the condition of
a particular accessory, look for obvious defects such as a broken mounting
hardware, housing or case. If a rust colored powder is present suspect
failure near and around the accessory in question.
- Check Timing belt or Chain: Your engine is designed to
utilize a timing belt or chain to rotate the camshaft that controls intake
and exhaust valve operation. If this belt or chain becomes lose or is
failing it can cause a rattle noise that will follow engine RPM. To check
for this condition on a timing belt engine remove the timing belt front
cover and using a flashlight check for component failure such as a timing
belt tensioner bearing or a timing belt that has started to come apart and
contacting the outer cover.
- Check Engine Flex plate (flywheel): If your car has an
automatic transmission the engine utilizes a flex plate. This flex plate is
connected to the engine crankshaft and is used to allow the starter motor to
engage and crank the engine over. If this flex plate becomes fractured or is
lose to can produce a rattling noise. To check for this condition remove the
flex plate cover and inspect the flex plate. Look for rust colored powder
either at the crankshaft bolts or the torque converter mounting bolts. Also
look for obvious cracks or missing/lose bolts. If any of these conditions
occur repair or replacement is necessary.
- Inspecting Clutch: If your car is equipped with a
standard transmission a
clutch assembly is used to disengage the
engine
from the transmission. If component fails it can allow parts of the clutch
to become dislodged creating a rattling sound as these parts are thrown
around the bell hosing of the transmission. This noise can change as the
clutch pedal is engaged and disagreed. If this is the case with your car the
transmission and clutch assembly must be removed to repair or replaced as
needed.
- Inspect Harmonic Balancer: The
harmonic balancer on
your engine is used to help silence engine vibration by utilizing a rubber
mounting metal ring attached to a hub that is connected to the front of the
engine. If this ring becomes dislodged because the rubber insulator has
failed it will allow the outer ring to bounce and jump on the rotating hub.
This condition will produce a rattling noise that change with engine speed.
To check for this condition
remove the multi rib belt and check the harmonic balancer condition. If
the outer ring is lose replacement is required.
Failed Harmonic Balancer
- Check Clutch Fan Operation: The
clutch fan on your
engine
is designed to engage and disengage as the engine heats up and cools down.
If this component fails it can allow the main shaft of the clutch fan to
have excessive clearance allowing the main housing to bounce producing a
rattling noise. To check for this condition (engine off) grasp the fan blade
and check for excessive movement. Usually this condition will be accompanied
by the engine running hot or overheating, but not always. The clutch fan
should also be able to turn in either direction if any of these conditions
occur replace the fan clutch with a new unit and recheck.
- Inspecting Dash and Interior Components: Many interior
components exist to configure the inner workings of your car. The majority
of these components exist in the dashboard including heater/air conditioner
ducting and controllers. There are many brackets and braces that are used to
hold these components in place. If any of these braces or brackets become
lose or broken a rattling noise can occur. The main objective is to locate
the point of origin to start the procedure that will repair the problem.
Other contributors of interior rattle sounds are the doors. Inside the doors
in your car contain
window and
door latch controls
that are used to open and close both the window and door operation. This is
done utilizing many structural and mechanical components that can come lose
or fail allowing clearances that can produce a rattle. To inspect for this
condition the inner
door panel must be removed. Once the door panel has been removed check
for any brackets or braces that have been broken or any bolts that are
missing. Replace or repair as needed and reassemble to recheck.
- Rattling Noise When Air Conditioner is On - The
air
conditioner is designed to operate using a electromagnetic clutch assembly
that receives a command signal from the activation switch. This command
controls when electricity is supplied to the compressor clutch that
engages and disengages the air conditioner system. If this clutch fails or
partially fails it can cause a rattling sound. to check for this condition
inspect the condition of the air conditioner clutch, it should be intact
with no lose moving parts. If the clutch ahs failed replacement is required.
(Note: some air conditioner clutches can be replaced without replacing the
entire air conditioning compressor.)
RATTLE NOISE CONTINUED-->>
For exact specific repair procedures for any of the steps above visit
our
car repair
manuals page.
Car Noises /
Rattling Noise
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