Your car communicates through sounds. A healthy vehicle has a predictable set of noises, and when something changes – a new squeal, grinding, clunking, or whine – it is telling you something needs attention. Learning to identify these sounds can help you catch problems early before they become expensive repairs.
This guide covers the most common abnormal vehicle noises, what systems they typically come from, and what to do about them.
Squealing or Screeching When Braking
A high-pitched squeal that occurs only when you apply the brakes is almost always the brake pad wear indicator contacting the rotor. This is a built-in metal tab designed to make noise when the pad friction material is nearly worn through. It is your warning to replace the pads soon. If the squeal turns into a grinding noise, the pads are completely worn and the metal backing plate is cutting into the rotor, which will also need replacing. See our brake pad replacement guide for the full procedure.
Squealing from the Engine Bay at Startup or Under Load
A loud squeal from the front of the engine when you first start the car or when you turn the steering wheel or switch on the air conditioning usually points to the serpentine belt (drive belt). The belt may be worn, cracked, glazed, loose, or the belt tensioner may be failing. A belt that squeals only when wet (in rain) often just needs replacing. If the noise persists after fitting a new belt, the tensioner pulley or one of the driven accessory pulleys may have a worn bearing.
Clicking or Ticking from the Engine
— /wp:heading –>A rhythmic ticking or clicking from the engine that speeds up with RPM can have several causes. On engines with hydraulic valve lifters, a ticking at cold startup that fades after 30 seconds to a minute is often normal as the lifters fill with oil. If the ticking persists when warm, one or more lifters may be worn or stuck.
On engines with adjustable valve clearances (common in older vehicles and many diesel engines), a tapping noise may indicate the valve clearances are out of specification and need adjusting. Your workshop manual lists the correct clearances and the adjustment procedure, which typically involves feeler gauges and either a screw-and-locknut or shim adjustment.
A single, louder knock that is more of a “clunk” than a “tick” and is loudest at idle may indicate worn big-end or main bearings, which is a more serious condition requiring engine work.
Clunking or Knocking from the Suspension
Clunking sounds when driving over bumps, speed humps, or rough roads typically come from worn suspension components. The most common culprits are worn sway bar (stabiliser bar) end links, which are cheap and easy to replace, worn ball joints in the front suspension, worn control arm bushings, or worn shock absorber mounts.
To narrow it down, have someone rock the vehicle while you listen underneath to pinpoint the location. Worn components will often have visible play that you can see and feel. Your workshop manual includes the inspection procedure and the specifications for acceptable play in each joint.
Clicking When Turning (Front-Wheel or All-Wheel Drive)
A rhythmic clicking noise that occurs when turning at low speed (like in a car park) and gets faster as speed increases is the classic symptom of a worn CV (constant velocity) joint. CV joints are located at each end of the front driveshafts and are protected by rubber boots. When a boot tears, grease leaks out and dirt gets in, causing the joint to wear rapidly.
Inspect the CV boots for tears or grease splatter around the inside of the wheel. Replacing the CV joint or entire driveshaft early prevents the joint from failing completely, which can leave you stranded. Your workshop manual includes the driveshaft removal and CV joint replacement procedure.
Whining or Humming That Changes with Speed
A constant whine or hum that varies with vehicle speed (not engine RPM) and may change when turning suggests a wheel bearing is wearing out. The noise typically gets louder at higher speeds and often changes tone when you turn the steering slightly in one direction. Turning left loads the right bearing more, so if the noise gets louder when turning left, the right-side bearing is likely at fault.
A whining noise that changes with engine RPM rather than vehicle speed is more likely to be an alternator bearing, power steering pump, or transmission input shaft bearing. Isolating which accessory is causing the noise can sometimes be done by removing the serpentine belt briefly and running the engine to see if the noise disappears.
Rumbling or Roaring from Underneath
A rumbling or roaring noise from underneath the vehicle, especially one that gets louder over time, often indicates an exhaust leak or a failing exhaust component. Check for holes in the exhaust pipe, a rusted-through muffler, or a broken exhaust hanger that allows the exhaust to contact the underside of the vehicle. Exhaust leaks before the catalytic converter can also cause a check engine light due to incorrect oxygen sensor readings.
Hissing Under the Bonnet
A hissing sound from the engine bay can indicate a vacuum leak (air escaping through a cracked hose or loose connection in the intake manifold) or a coolant leak where pressurised coolant is escaping as steam. A vacuum leak will typically cause rough idle and possibly a check engine light with lean fuel mixture codes (P0171/P0174). A coolant leak will produce a sweet smell and may leave visible wet spots or steam. See our engine overheating guide for more on cooling system leaks.
Using Your Workshop Manual to Trace Noises
Once you have identified the general area and type of noise, your vehicle’s workshop manual provides the inspection procedures, component specifications, and torque values needed to diagnose and repair the issue properly. Suspension component specifications, valve clearance procedures, bearing replacement guides, and wiring diagrams for sensor-related faults are all included.
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