sharp noise. Often related to vehicle speed
caused by a loose or bent fan blade or stuck valve lifter. May be
indicative of low oil.
or thudding sound
be attributed to a loos shock absorber of exhaust pipe. If thud
is rhythmic and increases with speed, check tires for damage. If
while shifting may be sign of bad motor mounts, bad CV or U joint,
or low transmission fluid.
indicates worn connection rod bearings or crankshaft. Possibly loose
transmission torque converter
pitched tapping or rattling sound
indicative of a problem with octane level in gasoline or a problem
with automotive timing. Older cars can have timing adjusted while
newer cars have timing controlled by on-board computer.
pitched piercing metallic sound
|| When driving is likely due to brake wear sensors indicating replacement
necessary. When braking lightly it is usually a minor annoyance
treated with anti noise paste. Under heavy braking usually indicative
of needing new material brake pads.
shrill, sharp, noise
or worn belts (alternator, fan, timing, power steering, or A/C)
possible brake system issue (see Screeching).