Mazda CX-5 Clunking or Knocking Over Bumps: Causes (Australia)

The CX-5 is one of Australia's most popular SUVs, and with plenty of high-kilometre examples on the road, suspension noises are a common complaint. A clunk over speed humps, a knock on rough roads or a rattle from the front end is usually a worn rubber bush or link rather than anything dramatic. Some suspension noises do signal parts that affect steering and braking, though, so they're worth tracking down.

The DIY Mechanic app can rank the likely causes for your exact CX-5 and the noise you're hearing. Here's how to narrow it down first.

Why does my CX-5 clunk over bumps?

• Stabiliser (sway bar) links: among the most common sources of a front-end clunk or knock over bumps and uneven surfaces, especially at low speed.
• Sway bar bushes: worn bushes can cause a creak or clunk over speed humps and driveways.
• Strut top mounts: worn mounts can knock over bumps and sometimes make a noise when turning the steering at low speed.
• Control arm bushes: worn bushes can cause clunks over bumps and under braking, and can affect handling.
• Shock absorbers: worn shocks can knock and make the car feel floaty or bouncy.
• Loose items: a jack, spare wheel, tools or items in the boot can make surprisingly convincing suspension noises.

Is it safe to drive with a clunking noise?

A light clunk from a worn sway bar link is usually not an immediate danger, but it should still be fixed. Get the car checked promptly if the noise comes with steering wander, the car pulling to one side, a vibration through the wheel, uneven tyre wear or a change in braking feel. Worn ball joints and control arm parts affect how the car steers and stops, and in rare cases can fail.

How do I tell the noises apart?

What can I check myself?

• Empty the boot: remove loose items and check the spare wheel and jack are secure.
• Pinpoint the corner: front or rear, left or right? A passenger listening can help.
• Note the trigger: speed humps, turning, braking or rough roads. Use the table above.
• Check the tyres: uneven or feathered wear can point to worn suspension or alignment problems.
• Bounce test: push down firmly on each corner. A car that keeps bouncing may have worn shocks.

When should I see a mechanic?

Have it inspected if the noise is getting louder, comes with any steering or braking change, or you see uneven tyre wear. A mechanic can put the car on a hoist and check each joint, bush and link for play, which is far quicker than replacing parts by guesswork. If several parts are worn, ask about a wheel alignment after the repair.

To work out what's most likely causing your CX-5's noise, start a free diagnosis preview below.