Rattling Noise Under Car When Accelerating: Likely Causes and What to Do

Rattling noise under car when accelerating? It’s often a loose part on your exhaust. Pressing the gas puts load on the drivetrain, so a part that’s quiet at idle starts to rattle.

Here are the usual suspects:

• Loose heat shield: a metal rattle that fades at a steady speed
• Worn exhaust hanger: the rubber can dry out and crack, so the pipe sags and rattles
• Failing catalytic converter: the material inside breaks apart
• Worn muffler: parts inside break down and rattle, even with no hole

A heat shield is often the cheapest fix. One Ontario shop puts a hanger repair at about $50 to $150.

Not every rattle is the exhaust. A sound like marbles in a can may be engine knock, and that can harm the engine.

An exhaust leak can let fumes into the cabin. If you smell exhaust inside the car, don’t drive it more than you must. Have it checked right away.

Fix a rattle early, before a pipe drags on the road. For prices, read our guide to muffler replacement cost in Vancouver.