Description & examples Of Automotive Noises:
Noise is an undesirable sound, usually unpleasant in nature. Some noises
are operating noises of rotating parts and acceptable like engine tire & wind
noises. Other noises occurs when worn-out, loose bolts or physical &
mechanical failure of parts. Common automotive noises are,
Bang:- Loud sound like from a gun. Engine backfire is an example.
Boom:- Low pitch hollow thunder like sound or most likely bass drum
sound. Buzz:- A constant sound like an electric razor or electric motor felt
through steering wheel or floor when tear out engine mountings.
Chirp:- A bird like repetitive sound occurs when accessory drive belt
looses, worn or cracks.
Clang:- A sound like dropping a wrench on floor. A repeated ringing
metallic noise like a bell.
Clank:- A sound like hammer striking on an anvil or thick metal sheet.
Clicking or Tapping: A noise likes tapping a pencil on table, camera shutter
sound or worn-out or bad hydraulic lifters make such noise.
Clack:- This is similar to click but more harsh than a click. It is like the
sound of billiard balls striking each other.
Clunk:- A non repeated heavy bumping or thumping noise coming from a
bad shock absorber or strut mounts while driving over a bump or hole.
Flapping:- A repetitive noise like birds wings or a flag in strong wind often
heard when plastic parts, wheel well cover or engine lower plastic covers
break or loose. Soft top loose fabrics also makes such sound.
Grinding:- A metallic sound that occurs when two moving metal surface
contacts each other. Like brake noise when linings completely worn-out.
Hiss:- The sound like pressurized air or gas escaping through a small hole.
Punctured tire or cooling air leaks makes such noises.
Howl:- A mid range noise like strong wind blowing.
Knock:- The sound like someone knocking/tapping on door. Worn-out
connecting bush or cam rocker makes such noise.
Moan/Drone:- Sounds like blowing on the neck of a large bottle, cracked
mounting rubber or exhaust component contacted with underbody.
Ping:- The sound like marbles dropping into a can, Engine detonation, free
ignition etc.
Pop:- Sharp explosive noise like engine misfire or backfire.
Rattle:- The sounds like marbles shaking in a can. Loose exhaust bolts or
lightly contacting exhaust with body, brake caliper bolt loose or worn-out
makes such noises.
Roar:- Sound like large cat roaring or roaring fans in a football match.
Differential noise, road noise and heavy acceleration of large displacement
engine noise are described as roaring noise.
Rumble:- The sounds like exhaust muffler or car rolling over warning
stripes in the roads in rail gates, toll gates or approaching a bridge.
Scraping:- A relatively high pitched jeet-jeet-jeet noise make by brake disc
wear sensor contacting with disc or loose brake components.
Screech:- These are sounds like tire skids during hard brake.
Squeal:- The sounds like squeal during hard brake or during sharp
cornering in movies, Accessory drive belt loose or worn etc.
Tap:- Clicking sounds like tapping ruler on table or engine tappets or
hydraulic valve lifters noise.
Whine:- A very high pitched steady noise that of a jet engine or vacuum
cleaner. Transmission gears or worn bearings also make such noise.
Whistle:- A clear high pitched sound often described as wind leaking noise
through door jam or weather stripes.
Diagnosis Theory:
● System knowledge, including comparison with a well known system.
● System history, including repaired and usages pattern history.
● Knowledge of probable causes
