Automotive Technology/Vibration and Noise

This lesson will be on diagnosing Vibration and Noise problems in vehicles

Suspension

1. A knocking sound when going over bumps or turning corners likely means your worn-out shocks are causing your coil springs to vibrate wildly against your vehicle’s chassis.
2. A grunt or a squeak on bumps or turns means your front steering mechanism is wearing out. This can cause you to lose control of your steering.
3. Bad ball joints in your suspension have been described as sounding like rusty door hinges when you move up and down or back and forth.
4. Rattles are harder to diagnose, since many parts of the suspension can make this noise when starting to wear out.
5. A grinding noise, or popping noise while steering, almost always, and most notably when parked. When strut mounts wear out, the bearings inside of them typically fail, making it harder to steer the vehicle and putting additional strain on the steering system.

Steering

Clunk, Squeak, Click, or Creak

These noises usually indicated worn shocks, suspension bushings, ball joints or tie rods. These noises can also be accompanied by wandering, poor ride quality or vibrations.

Metallic grind or ring

These noises usually are from worn brake components. Look into replacing your either your pads, shoes or rotors.

Crunching or clicking while turning sharply

CV Joint should be replaced.

Hum

A hum usually indicates the wheel bearing is going bad. This should be checked out by a qualified mechanic.

Screech, Squeal or Whine

These sounds usually indicate a problem in your power steering system, either a lose belt, bad pump or low power steering fluid.

Engine

• Bang » Backfire caused by spark misfire or lean condition
• Boom » RWD drive shaft or u-joint problem
• Buzz » Bad interior trim part fit caused by wind
• Chirp » Belt related
• Clack » Engine / valve train related
• Clang » Heard through the drive shaft on RWD car
• Clank » Heard through the drive shaft
• Click » Engine / valve train related
• Clunk » Suspension related
• Flapping » Belt related
• Grinding » Brake related
• Groan » Suspension related
• Grunt » Brake or suspension related
• Hiss » Cooling system leak
• Hum » Bearing, rpm related, a/c related
• Knock » Engine related
• Ping » Caused by engine, fuel, timing, carbon
• Pop » Backfire
• Rattle » Exhaust system related
• Roar » Bad fan clutch, tire noise, muffler, transmission
• Rumble » Muffler, tire
• Scraping » Something moving and touching
• Screech » Brakes or belts
• Sizzling » Something burning, coolant/oil leak
• Squeal » Brakes or belts
• Tap » Engine / valve train related
• Thump » Suspension related
• Whine » Bearings, bad gear alignment
• Whistle » Air leaks, door gaskets, etc.

Automatic Transmission

Transmissions are generally not considered Vibration sources, given their design and restriction inside the case.