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Diagnosing Car Noises

Dan Ferrell writes about DIY car maintenance and repair. He has certifications in Automation and Control Technology and Technical Writing.

Strange car noises can appear suddenly as a sign of impending disaster. For example:

  • Clicking
  • Buzzing
  • Tapping
  • Growling

Modern cars can isolate regular noises coming from the engine, transmission, and rotating axles.

So it's not difficult to guess that a new sound means a potential problem somewhere.

However, these sounds are as varied as the problems that can follow. And diagnosing the source of a sound that wasn't there the last time you were behind the wheel can sometimes be hard to pinpoint.

Diagnosis of abnormal sounds begins with locating the area the sound is coming from and then identifying which components could be the source.

But not all sounds are that easy to diagnose. Vibration can easily travel through several components before it reaches our ears, hands, feet, or body, making it more difficult to trace it back to its source.

Below you will find different sections describing the most common sounds you can hear in your car and their possible causes. And at the end of this post, you will find a Resources section with a list of articles that go deeper in the diagnostic.

Have Your Repair Manual Handy

It's a good idea to have your car's repair manual handy when performing these diagnostics. If you don't already have the manual, you can buy a relatively inexpensive copy through Amazon.

Haynes manuals include:

  • Pictures
  • Step-by-step procedures
  • System and parts description
  • Diagnostics
  • Maintenance schedule
  • Installation and parts specifications
  • Electrical diagrams

Even if you use the manual just for car maintenance, you can recoup your small investment in your first project.

In This Article

  • I Hear a Buzzing
  • My Engine Squeals
  • I Hear a Click
  • What Makes My Wheels Growl?
  • My Transmission Growls
  • I Hear Loud Knocks
  • My Engine Produces Rhythmic Sounds
  • VIDEO: Engine Knocking Noise Diagnose and Fix
  • Why Are My Brakes Noisy?
  • I Can Hear Clicks When I Turn
  • A Growling, Squeaking, and Squealing Clutch
  • Resources
diagnosing-car-noises
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1. I Hear A Buzzing

If the buzzing is coming from the engine area, take a look at the alternator. A bad diode can produce this type of sound.

diagnosing-car-noises

2. My Engine Squeals

A squeal coming from under the hood can occur under a variety of circumstances:

  • When starting the engine
  • When accelerating
  • While the engine is running

Usually, a squeal comes from a loose or worn accessory belt, or pulley.

  • Check the belt. If it looks worn, replace it.
  • Check if any hose, support, or other part is rubbing against the belt.
  • If the belt seems in good condition, check for proper tension.
  • Remove the belt and check the intermediate, tension and accessory pulleys the belt runs on.

A pulley with a worn bearing can also cause screeching. If any pulley doesn't turn freely, replace it.

3. I Hear a Click

If you hear the engine clicking with a regular and steady rhythm during idle, it is possible that:

  • One or more valves need adjustment.
  • A rocker arm is loose.
  • One or more valve tappets are dirty.
  • An accessory is loose.

Also, a clicking sound may come from a leak in the exhaust manifold.

If the click comes from the transmission, worn teeth on an input or intermediate shaft (transaxle), or gears can cause these sounds.

4. What Makes My Wheels Growl?

A growling noise can come from a worn or damaged wheel bearing.

Symptoms include:

  • The sound changes with vehicle speed.
  • The sound is louder when the vehicle is moving.

5. My Transmission Growls

If the growl is coming from the transmission when the vehicle is moving, check the front or rear intermediate shaft bearings for wear or damage (transaxle); or the output shaft rear bearing for wear or damage (transmission).

If the growling noise comes from the transmission when in neutral, check the front or rear input shaft bearings for damage (transaxle); or the bearings for wear or damage on the input shaft, countershaft gear, or auxiliary idler shaft.

If the growling noise is heard in all gears except direct drive, the output shaft pilot roller bearing is likely worn or damaged.

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6. I Hear Loud Knocks

Engine knocks are dangerous and can be caused by a loose timing chain, or some other problem. See the Resources section at the bottom for help on diagnosing engine knocking.

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7. My Engine Produces Rhythmic Sounds

Low-pitch sounds that increase in speed along with the engine (similar to the rhythmic, high-pitch sound produced in the valve train) may come from worn pistons or piston components.

Sounds can range from clicks, bell-like sounds, metallic taps, and loud snaps.

  • If the engine does not have a lot of mileage, check the oil level. The problem could in the lubrication system as well. Check oil pressure and compare to the specifications in your manual.
  • If the engine has a lot of miles, internal engine sounds may come from worn rings, worn cylinder walls, worn piston pins, or bearings.
  • A metallic sound can also come from a loose timing chain.

The following video shows an example of a vehicle with a noise coming from the block and what was causing the noise. The guy who owns the vehicle decided to go for a temporary solution. Usually, engine block noises require a more expensive job to produce a more permanent fix.

8. Why Are My Brakes Noisy?

When it comes to brakes, noise is perhaps one of the most common problems reported by car owners.

The main reason is worn brake pads. A high-pitched squeal is usually heard each time the brakes are applied. In this case, you simply have to change the brake pads and perhaps the discs (depending on wear) to solve the problem.

However, other sounds in the system can also occur without the driver pressing the brake pedal. In this case, there may be a problem with a brake support component.

Noises coming from the wheels such as a rattle, clicking, grinding, and hammering must be diagnosed and corrected soon because it could jeopardize the operation of the brake system.

Not All Brake Noises Are Signs of Problems

Not all brake noises are necessarily bad. Take, for example, the screeching sound that occurs when braking hard in a car with antilock brake system (ABS). This does not indicate that there is something wrong with the system.

The ABS system causes the tires to skid intermittently, about 20% of the braking time, to prevent the car from spinning out of control. This slippage is what causes the squeak.

Still, if you have any concerns about abnormal brake noise, it's best to see an auto technician to verify that there isn't a serious problem.

9. I Can Hear Clicks When I Turn

Problems with a constant velocity joint (CV joint) can produce noises not only when turning a corner, but when accelerating, decelerating, or driving within a specific speed range.

  • If you hear a pop or click sound every time you turn left or right, check the outer CV Joint.
  • If you hear a knock when accelerating, decelerating, or when putting the transmission in Drive, it is most possible that there is excessive play in the inner CV Joint.
  • A humming or grunting noise may come from a poorly lubricated inner or outer CV Joint, or perhaps a worn or damaged tire bearing.
  • A cyclical vibration that occurs between 45 and 60 mph (72 and 100 km) may come from a failed inner tripod CV Joint.

10. A Growling, Squeaking, and Squealing Clutch

The clutch assembly, in a manual transmission, can also be a rich source of ominous sounds. These are the most common.

  • If you hear a growling noise when you start the engine with the transmission in neutral, without touching the clutch pedal, check the input shaft bearing.
  • If you hear a squeaking noise, slowly press the clutch pedal. If the sound disappears, the clutch fork and pivot need to be lubricated. Instead, if the sound gets louder, the problem is with the release bearing.
  • If you hear a squealing noise that changes when you press or release the clutch pedal, the problem is the pilot bearing.

Resources

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2022 Dan Ferrell

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