Why Is My Car Making a Strange Noise?
Cars make plenty of normal sounds.
The engine runs.
The tires roll across the pavement.
The transmission changes gears.
The cooling fan turns on.
The air conditioning compressor cycles.
After driving the same vehicle every day, you become familiar with what all of that normally sounds like.
That's why a new sound tends to get your attention.
Maybe there's suddenly a squeal when you start the engine.
A clicking noise when you turn.
A humming sound that gets louder with speed.
A clunk every time you hit a bump.
Or a grinding noise when you press the brakes.
What does it mean?
There isn't one answer because different sounds can come from completely different parts of the vehicle.
The best thing you can do is pay attention to what the noise sounds like, when it happens, and where it seems to be coming from.
Here's a guide to some common vehicle noises and what they may be telling you.
First, Don't Ignore a New Noise
Not every unusual sound means your vehicle is about to break down.
Some problems are relatively minor.
Others can become serious if they're ignored.
A new noise is information.
Ask yourself:
When did it start?
Does it happen while the vehicle is moving?
Does it happen while sitting still?
Does speed affect it?
Does it happen when braking?
Does it happen when turning?
Does it happen during acceleration?
Does it change when you hit a bump?
Is the engine cold or warm?
Are any warning lights illuminated?
The answers can make diagnosing the problem much easier.
1. Squealing When You Start the Engine
A high-pitched squeal from under the hood may involve a belt or one of the components driven by it.
Modern vehicles commonly use a serpentine belt to operate accessories such as:
Alternator
Air-conditioning compressor
Power-steering pump on some vehicles
Water pump on certain engines
Other accessories
If the belt slips or becomes worn, you may hear squealing.
What Causes a Belt to Squeal?
Possible causes include:
Worn belt
Loose belt tension
Contamination
Worn tensioner
Pulley problems
Accessory problems
Moisture
A brief noise under certain conditions and a constant loud squeal aren't necessarily the same problem.
Have the belt system inspected if the noise persists.
Can You Keep Driving With a Squealing Belt?
That depends on the cause.
If the belt fails completely, you could lose operation of important accessories.
Depending on the engine design, that might include the alternator or water pump.
That could eventually lead to:
Battery discharge
Loss of electrical power
Engine overheating
Other problems
A persistent belt noise shouldn't be ignored.
2. Grinding When You Brake
A grinding noise during braking deserves attention.
Your braking system relies on friction to slow the vehicle, but it shouldn't normally sound like metal grinding against metal.
Possible causes can involve:
Severely worn brake pads
Brake rotor damage
Debris
Caliper problems
Other braking components
If the noise happens consistently when braking, have the brakes inspected.
Why Worn Brake Pads Can Grind
Disc brakes use pads that press against a rotating brake rotor.
The pads contain friction material designed to wear gradually.
If that material becomes severely worn, metal components may begin contacting the rotor.
That can produce a harsh grinding sound.
Waiting can turn a brake-pad service into a more expensive repair involving additional components.
What If the Brakes Only Grind After Rain?
A brief scraping or grinding sound during the first few stops after the vehicle has been parked in wet weather can sometimes come from light surface rust on the brake rotors.
Brake rotors contain iron and can develop a thin layer of rust relatively quickly.
Normal braking may clean it from the rotor surface.
If the noise continues, becomes severe, or braking performance changes, have the system inspected.
3. Squeaking When You Brake
Brake squeaking doesn't always mean the brakes are dangerously worn.
Possible causes can include:
Brake-pad material
Moisture
Dust
Surface rust
Wear indicators
Glazing
Other brake conditions
Some brake pads are designed with wear indicators that intentionally create noise when the pads become worn.
If your brakes suddenly begin squealing consistently, an inspection can determine why.
4. Clicking When You Turn
A repetitive clicking or popping noise during a turn can sometimes involve a CV joint.
CV stands for constant velocity.
CV joints are used on many front-wheel-drive and all-wheel-drive vehicles to transfer power to the wheels while allowing the suspension and steering to move.
A damaged CV joint may create a clicking sound, especially during tighter turns while accelerating.
What Causes CV Joint Problems?
CV joints are protected by flexible rubber or plastic boots containing grease.
If a boot tears, grease can escape and contamination can enter.
Over time, the joint may wear.
One clue can be grease sprayed around the inside of a wheel or suspension area.
If you hear repetitive clicking during turns, have the axle and CV joints inspected.
5. Humming That Gets Louder With Speed
A humming or droning sound that changes with vehicle speed can have several possible causes.
These include:
Tires
Wheel bearings
Drivetrain components
Differential
Other rotating components
The important clue is that the sound changes with vehicle speed rather than engine speed.
Could It Just Be Tire Noise?
Absolutely.
Different tires produce different amounts of road noise.
Noise can also increase because of:
Uneven tread wear
Cupping
Aggressive tread patterns
Low pressure
Tire damage
Road surface
Winter tires
A vehicle may sound louder on rough concrete than smooth asphalt.
Try noticing whether the sound changes dramatically on different road surfaces.
6. Growling or Humming From a Wheel
A worn wheel bearing can create a humming, growling, or rumbling noise.
Wheel bearings allow the wheels to rotate smoothly while supporting the vehicle's load.
As a bearing wears, the noise may increase with speed.
It may also change when the vehicle turns because the load on the bearing changes.
Can You Tell Which Wheel Bearing Is Bad by Turning?
Sometimes changes in noise during turns can provide clues.
But sound travels through a vehicle.
The side you think is making the noise isn't always the side with the problem.
A proper inspection is more reliable than replacing a wheel bearing based on where the noise seems to come from.
7. Clunking Over Bumps
If you hear a clunk every time you hit a pothole, speed bump, or rough section of road, the suspension may deserve attention.
Possible sources include:
Sway-bar links
Control-arm bushings
Ball joints
Struts
Shocks
Strut mounts
Other suspension components
Loose items elsewhere on the vehicle can create similar sounds too.
Why Suspension Noises Matter
The suspension doesn't simply make your ride comfortable.
It helps control the tires and maintain stable contact with the road.
Worn suspension components may affect:
Handling
Steering
Tire wear
Ride quality
Alignment
Vehicle stability
If a clunk is getting louder or the vehicle's handling has changed, have it inspected.
8. Rattling Under the Vehicle
A rattle underneath the vehicle could come from several places.
One relatively common source is a loose exhaust-system heat shield.
Heat shields are installed around certain exhaust components to protect nearby parts from high temperatures.
Over time, mounting points can corrode or loosen.
That can create a metallic rattle.
Could a Rattle Be the Exhaust?
Yes.
Possible exhaust-related noises can involve:
Heat shields
Exhaust hangers
Pipes
Muffler
Catalytic converter
Connections
Internal components
If you hear a rattle underneath the vehicle, don't crawl under a vehicle supported only by a jack.
Have it safely inspected.
9. Loud Exhaust Noise
Has your vehicle suddenly become much louder?
An exhaust leak is one possible cause.
Depending on where the leak occurs, you may hear:
Ticking
Puffing
Hissing
Rumbling
Roaring
Exhaust problems can also allow fumes to enter areas where they shouldn't.
If you smell exhaust inside the passenger compartment, take it seriously.
Why Exhaust Fumes Are Dangerous
Vehicle exhaust can contain carbon monoxide, a gas that is colorless and odorless.
A damaged exhaust system can potentially allow dangerous gases to enter the cabin.
If you suspect exhaust fumes are entering the vehicle, stop using the vehicle and have the problem addressed.
Don't rely on smell alone to determine whether carbon monoxide is present.
10. Ticking From the Engine
Engines naturally make mechanical sounds.
Some engines are louder than others.
Fuel injectors, direct-injection systems, and valvetrain components can produce ticking sounds during normal operation.
The important question is whether the noise is new or different.
A new ticking sound can potentially involve:
Low engine oil
Valvetrain components
Fuel injectors
Exhaust leak
Other engine components
Start by checking the engine oil level according to the owner's manual.
Low Oil and Engine Noise
Engine oil lubricates moving components.
If the oil level becomes dangerously low, engine damage can occur.
If you hear a new engine noise and the oil-pressure warning light is illuminated, treat the situation seriously.
An oil-pressure warning isn't simply a reminder to schedule an oil change.
It may indicate that the engine isn't receiving adequate oil pressure.
11. Knocking From the Engine
"Knocking" can describe several different sounds, which makes this one tricky.
A light pinging noise during acceleration isn't necessarily the same as a deep mechanical knock from inside the engine.
Possible causes vary widely.
A persistent deep knocking noise can indicate a serious engine problem.
If the sound is loud, new, and clearly mechanical, avoid continuing to drive normally until the vehicle is inspected.
Does Premium Gas Stop Engine Knocking?
Not every engine requires premium fuel.
Use the octane rating recommended by the vehicle manufacturer.
If the engine is designed for regular gasoline, filling it with premium doesn't automatically repair a mechanical problem.
If you're hearing persistent knocking or pinging despite using the correct fuel, have the vehicle diagnosed.
12. Hissing Under the Hood
A hissing sound can potentially involve:
Vacuum leak
Cooling-system leak
Air intake leak
Pressurized hose
Other components
If the hissing is accompanied by steam, rising engine temperature, or coolant smell, the cooling system may be involved.
Be careful around an overheating engine.
Never Open a Hot Cooling System
If the engine is overheating, don't immediately remove the radiator cap or pressurized coolant-reservoir cap.
Hot coolant can be under significant pressure.
Opening the system while hot can release boiling coolant and steam.
Allow the vehicle to cool and follow the manufacturer's instructions.
13. Squeaking Over Bumps
A squeak over bumps may involve suspension bushings, joints, or other components.
Temperature and moisture can sometimes affect suspension noises too.
Pay attention to whether the squeak occurs:
Over every bump
Only when cold
While turning
When entering driveways
When passengers get in or out
While rocking the vehicle
These clues can help locate the source.
14. Popping When Turning the Steering Wheel
A pop or clunk during steering can potentially involve:
Steering components
Suspension joints
Strut mounts
CV joints
Other components
If the steering itself feels loose, stiff, or unpredictable along with the noise, have the vehicle inspected promptly.
Steering problems directly affect vehicle control.
15. Whining While Turning
On vehicles equipped with hydraulic power steering, a whining sound during steering can sometimes indicate a problem involving:
Low power-steering fluid
Power-steering pump
Air in the system
Leaks
Other steering components
However, many newer vehicles use electric power steering and don't have traditional hydraulic power-steering fluid.
Know which system your vehicle uses before searching for a reservoir that may not exist.
16. Whining That Changes With Engine Speed
A whining noise that changes when engine RPM changes may involve an engine-driven accessory.
Potential sources include:
Alternator
Power-steering pump on applicable vehicles
Pulley
Bearing
Air-conditioning compressor
Other accessories
A technician may need to listen to individual components to locate the source.
17. Clicking When You Try to Start the Car
You turn the key or press the start button and hear:
Click.
Maybe several clicks.
But the engine doesn't start.
A clicking sound during starting can involve:
Weak battery
Poor battery connection
Starter
Electrical problem
Other starting-system components
A rapid series of clicks is commonly associated with insufficient electrical power reaching the starter.
Don't Automatically Buy a New Battery
A dead battery doesn't always mean the battery itself is defective.
The battery may have discharged because:
Lights were left on
Vehicle sat for a long time
Charging system has a problem
Battery connection is poor
There is an electrical drain
Cold weather reduced available power
Testing the battery and charging system can help determine the actual cause.
18. Grinding When Starting the Engine
A grinding sound during starting may involve the starter or the way its gear engages with the engine.
Don't repeatedly continue trying to start the vehicle if you hear severe grinding.
Repeated engagement could potentially damage additional components.
Have the starting system inspected.
19. Roaring During Acceleration
A roaring sound that becomes louder during acceleration can have several possible causes.
These may involve:
Exhaust system
Engine air intake
Transmission
Drivetrain
Tires
Other components
If the vehicle suddenly becomes dramatically louder than usual, check whether the sound follows engine RPM or vehicle speed.
That distinction is useful.
Engine Speed vs. Vehicle Speed
Here's a simple way to think about it.
If the sound changes primarily when the engine revs, even when vehicle speed doesn't change much, it may be related to the engine or an engine-driven component.
If the sound gets louder primarily as the vehicle travels faster, tires, wheel bearings, or drivetrain components may deserve more attention.
That's not a diagnosis.
It's simply a useful clue.
20. Transmission Whining or Humming
Transmissions contain numerous moving components.
A new whining, humming, grinding, or clunking sound that appears during shifting or changes with transmission operation deserves inspection.
Also pay attention to:
Delayed engagement
Slipping
Harsh shifts
Warning lights
Fluid leaks
Burning smell
Unusual RPM behavior
Noise is more useful diagnostically when considered alongside other symptoms.
21. Clunking When Shifting Into Drive or Reverse
A small change in sound or movement when selecting a gear can be normal.
A loud new clunk isn't something to ignore.
Possible causes may involve:
Engine mounts
Transmission mounts
Drivetrain components
CV joints
U-joints
Other components
If the vehicle also jerks excessively when shifting, have it inspected.
22. Chirping From a Wheel
A repetitive chirp that speeds up as the vehicle moves faster may come from a rotating component.
Possible sources can include:
Brake components
Wheel or tire
Bearing
Dust shield
Other rotating parts
The fact that the chirp speeds up with the vehicle can help determine where to start looking.
23. Scraping While Driving
A scraping noise should be investigated.
Potential causes include:
Loose splash shield
Brake component
Bent brake dust shield
Debris
Damaged underbody panel
Dragging exhaust component
Other parts
Sometimes something simple, such as a loose plastic underbody panel, can create an alarming noise.
Other times, scraping can indicate a more serious issue.
Check for Anything Hanging Down
From a safe position outside the vehicle, look underneath without crawling beneath it.
Can you see:
Loose plastic
Hanging exhaust
Debris
Damaged shield
Something dragging
If something is contacting the road, don't continue driving at highway speed until you know what it is.
24. Tire Thumping
A rhythmic thumping sound can involve a tire.
Possible causes include:
Flat spot
Tire damage
Tread separation
Foreign object
Severe uneven wear
Very low pressure
A damaged tire can become a serious safety concern.
If you hear a new repetitive thump, inspect the tires before continuing a long drive.
What Is Tread Separation?
A tire is built from multiple layers.
If those layers begin separating, the tire may develop a bulge or distorted shape.
You may feel or hear:
Thumping
Vibration
Vehicle shaking
Handling changes
If you suspect structural tire damage, stop driving normally and have the tire inspected.
25. Wind Noise That Suddenly Gets Louder
Not every strange vehicle noise is mechanical.
A sudden increase in wind noise can involve:
Door seal
Window seal
Loose exterior trim
Roof rack
Sunroof
Body panel
Mirror
Weatherstripping
If the noise started after body work, windshield replacement, or installation of an accessory, that information may help locate the problem.
26. Water Sloshing
Hearing liquid moving around inside the vehicle can be confusing.
Possible sources may include:
Water trapped in a door
HVAC drainage issue
Cooling-system air
Water intrusion
Fluid reservoir
Other areas
If you notice wet carpet, musty odors, or water inside the cabin along with the sound, look for a leak.
27. Fan Noise Behind the Dashboard
The climate-control system uses a blower fan to move air through the vents.
If leaves or debris enter the blower area, you may hear:
Ticking
Fluttering
Rattling
Scraping
A failing blower motor can also create unusual sounds.
If the noise changes directly with the HVAC fan-speed setting, that's a useful clue.
Why Does the Noise Only Happen With the A/C On?
If a noise begins only when the air conditioning is activated, components in the A/C system may be involved.
Possible sources include:
Compressor
Clutch on applicable systems
Pulley
Blower motor
Cooling fan
Other HVAC components
The timing helps narrow the search.
28. Cooling Fan Noise
Electric cooling fans can become surprisingly loud when they switch on.
That's not necessarily a problem.
The fans may run to help control:
Engine temperature
Air-conditioning performance
Other thermal conditions
However, a fan that makes grinding, scraping, or severe vibration noises may need inspection.
Some Vehicles Are Simply Noisier Than Others
A pickup truck with aggressive all-terrain tires isn't going to sound exactly like a luxury sedan.
A direct-injection engine may make more noticeable ticking than another engine.
A diesel engine has different normal sounds from a gasoline engine.
A cold engine may sound different from a fully warmed engine.
The question isn't always:
"Is this vehicle completely silent?"
It's:
"Is this sound normal for this vehicle, or did something change?"
Cold Weather Can Change Vehicle Sounds
Indiana winters can make vehicles sound different.
Cold temperatures affect:
Rubber
Fluids
Belts
Tires
Suspension components
Engine operation
Exhaust systems
A vehicle may be noisier during the first few minutes after a cold start.
Some sounds disappear as the vehicle warms.
A loud, persistent, or worsening noise still deserves attention.
Don't Turn Up the Radio to Fix It
We've all done it.
The car makes a weird noise.
You turn up the radio.
Problem solved.
Except, of course, it isn't.
A sound is often your first warning that something has changed.
Catching a problem early may prevent:
Breakdown
Additional damage
Uneven tire wear
More expensive repairs
Safety issues
Listen to your vehicle.
When Should You Stop Driving?
Some noises deserve more urgency than others.
Safely stop driving and seek assistance if the noise is accompanied by:
Oil-pressure warning
Overheating
Smoke
Strong burning smell
Severe grinding
Loss of braking ability
Sudden steering changes
Severe vibration
Visible tire damage
Major loss of power
Flashing check engine light with rough running
Don't continue driving simply because the vehicle is technically still moving.
Record the Noise
One surprisingly useful thing you can do is record the sound with your phone, as long as you're not handling the phone while driving.
Have a passenger record it, or capture the noise while safely parked if possible.
Intermittent noises have an annoying habit of disappearing as soon as you arrive at the repair shop.
A recording may help demonstrate what you've been hearing.
Describe the Noise Clearly
When talking to a technician, try to provide more information than:
"It makes a weird sound."
Instead, say:
"It clicks when I make a tight right turn."
"It grinds when I brake below 20 mph."
"It hums above 55 mph."
"It squeals for about ten seconds after a cold start."
"It clunks over bumps."
"It only rattles when the A/C is on."
Those details can save diagnostic time.
Pay Attention to Where It Comes From
Does the noise seem to come from:
Front of the vehicle?
Rear?
Driver's side?
Passenger's side?
Under the hood?
Under the floor?
Near one wheel?
Behind the dashboard?
You don't need to identify the exact component.
Simply identifying the general area can help.
Don't Try to Diagnose Everything by Sound Alone
A sound can provide clues.
It isn't always enough for a complete diagnosis.
For example, a humming noise could potentially come from:
Tire
Wheel bearing
Differential
Transmission
Road surface
Other rotating component
That's why replacing parts based on a five-second internet video isn't a great strategy.
Use the sound as the starting point.
Then inspect and test.
Strange Noises During a Used-Car Test Drive
When shopping for a pre-owned vehicle, turn the radio down for part of your test drive.
Listen.
Pay attention during:
Cold start
Idle
Acceleration
Braking
Turning
Bumps
Highway driving
Parking maneuvers
Air-conditioning operation
A test drive isn't only about whether you like how the vehicle looks.
It's your opportunity to see, feel, and hear how it operates.
Listen When Starting the Vehicle
Start the engine and let it idle.
Does it start quickly?
Does the engine idle smoothly?
Do you hear:
Grinding?
Loud knocking?
Persistent squealing?
Unusual rattling?
A few seconds of normal cold-start noise can vary by vehicle.
You're looking for something clearly unusual or inconsistent.
Listen During Braking
Turn the radio down and brake normally.
Pay attention to:
Grinding
Squealing
Clicking
Vibration
Pulsation
Pulling
Brakes are one of the most important systems on the vehicle.
Don't ignore something that feels or sounds wrong.
Listen During Turns
Try normal left and right turns.
Listen for:
Clicking
Popping
Clunking
Grinding
Also notice whether the steering feels smooth.
A sound that appears only while turning can provide useful information about steering, suspension, or drivetrain components.
Listen at Highway Speed
When conditions and the test-drive route safely allow it, see how the vehicle sounds at normal highway speed.
Pay attention to:
Tire noise
Humming
Wind noise
Vibration
Drivetrain noise
A problem that isn't noticeable around a parking lot may become obvious at 60 mph.
Ask Questions
If you hear something you don't recognize, ask about it.
Not every noise means the vehicle has a major problem.
But you should understand what you're hearing before making a purchase.
A reputable seller shouldn't have a problem with you asking questions about how a vehicle operates.
Your Car Is Constantly Giving You Information
Dashboard lights are one way a vehicle communicates.
Sounds are another.
A squeal.
A click.
A hum.
A clunk.
A grind.
A rattle.
None of these automatically tells you exactly which part needs replacement.
But they can tell you that something has changed.
The sooner you notice that change, the sooner you can determine whether it's harmless or needs attention.
Find Your Next Vehicle at Big City Cars
At Big City Cars in Fort Wayne, shoppers can compare pre-owned cars, trucks, SUVs, and crossovers for a variety of driving needs.
When you're test-driving your next vehicle, don't just look at the features.
Listen to it.
Turn the radio down.
Drive at different normal speeds.
Test the brakes.
Make a few turns.
Listen over bumps.
See how the vehicle behaves.
And if your current vehicle suddenly starts making a strange noise, don't immediately assume the worst.
Start with three questions:
What does it sound like?
When does it happen?
Where does it seem to come from?
Those answers can provide valuable clues and help you figure out what your vehicle is trying to tell you.
