Symptoms
- Noise (clunk, rattle, or bang) only on rough roads, potholes, or gravel
- Silent or much quieter on smooth pavement
- May be felt as well as heard
- Could come from the front, rear, or seem to move around depending on the bump
Likely causes
- CommonWorn suspension bushingsBushings that have hardened or cracked allow extra movement that's only revealed by real impacts.
- CommonLoose heat shield or exhaust hangerThese often only rattle audibly with the extra jolt of a rough road.
- PossibleLoose or worn sway bar end linkA common source of clunking specifically over bumps.
- PossibleItems in the trunk or cargo area shiftingLoose cargo can create noise that seems mechanical but isn't.
- PossibleWorn strut mount or shock absorberWorn shocks/struts can allow extra suspension movement and noise over bumps.
What to do
- Check the trunk, cargo area, and under seats for loose items that might be shifting and causing noise, since this is an easy and free thing to rule out first.
- Have someone drive slowly over a known bump or rough patch while you listen from outside the car (safely) to help localize the noise.
- Visually inspect sway bar end links and bushings for cracking, looseness, or visible wear if you're comfortable doing so.
- Check heat shields and exhaust hangers, since these very commonly only make noise under the extra vibration of rough roads.
- Have a mechanic put the car on a lift and use a pry bar to check for play in suspension bushings, ball joints, and end links.
- Note whether the noise seems to come from the front or rear, or one side versus the other, and share this with the mechanic.
- Address worn suspension components reasonably promptly, since they affect handling and tire wear in addition to causing noise.
- Avoid ignoring a rough-road-only noise indefinitely, since components under this kind of intermittent stress often fail more suddenly than gradually.
Tools and parts
- Flashlight
Sway bar end linkSearch: “sway bar end link for [year make model]”
Suspension bushing kitSearch: “suspension bushing kit for [year make model]”
When to call a pro
A rough-road-only noise is best diagnosed by a mechanic on a lift, using a pry bar to check suspension components for play that isn't obvious just by looking.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.