Car Noises / Rattling Noise

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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.)

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
   
• 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.
   
  

  How to Change Front Brake Pads and Rotors

• 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 manual is 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

For exact specific repair procedures for any of the steps above visit our car repair manuals page.

Car Noises / Rattling Noise

Check Manufacturer Specific Rattling Noise Questions and Answers

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