The more common causes of a rattle on start up are worn engine mounts. The engine mounts can make more noise on starting the vehicle, when gears are changed, or when slowing down or accelerating hard.
If a rattling sound is coming from directly underneath your car, that’s a strong sign that something is wrong with your exhaust system. Other sounds usually aren’t as serious and may involve replacing the muffler or a corroded pipe section. Under the hood, rattling noises suggest the water pump is ready to fail.
What’s making a rattling noise under my car? The fix: Inspect your heat shields for corrosion and looseness. Retighten or replace them if necessary. The fix: Have your mechanic check your exhaust system checked by your mechanic or a local muffler shop. The fix: Remove and replace your catalytic converter.
Most people describe a bad wheel bearing as making a growling or rumbling noise (the sound is often mistaken for worn tires). Also, in some cases, a bad bearing may make a high-pitched grinding or squealing sound. In either case, the frequency of the sound will correspond to the rotation of the tires.
Rattling Noises. Your catalytic converter consists of small, honeycomb-shaped components that can cause a rattling sound when broken. If your catalytic converter is broken, this rattling should be loudest when the car starts, and should get worse over time.
If you hear a pinging or rattling sound when accelerating, low-octane fuel could be the cause. Pinging (also called pre-ignition or detonation) can also be the result of carbon deposits, a bad knock sensor, overheating or incorrect ignition timing.
Check for Bad Sway Bar Links Sway bar links tend to rattle or make knocking sounds when driving over bumps. If you usually hear a rattling noise when driving over bumps, there’s a good chance it could be the sway bar links. If you hear a rattling noise, it’s time to replace the sway bar links.
If the loud muffler is due to a hole, the vehicle is dangerous to drive and should be inspected by a mechanic right away. It is possible that a broken piece of the muffler may have come off and is rattling in the exhaust system, which can cause the clunking sound.
What are the symptoms of bad wheel bearings A humming, rumbling or growling noise that increases with acceleration or as the vehicle turns. A loud constant whining or grinding noise when the vehicle is in motion. Clunking noises when driving over uneven road surfaces.
Here are some indicators of a worn wheel hub bearing or other wheel -end damage: Snapping, clicking or popping. Grinding when the vehicle is in motion. Knocking or clunking. Humming, rumbling or growling. Wheel vibration and/or wobble. Shudder, shimmy or vibration at a constant speed.