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Get to Know the Different Types of Valve Train Noise
The valve train noise is
usually due to the excessive
clearance two internal
engine parts such as a
broken valve spring or a
worn out camshaft lobe.
The sound frequency of the
valve train noise is one-half
the crankshaft speed and a
clicking lifter is a common
valve train noise.
The problem with
diagnosing and correcting
valve train noise is that
there are many components
that can cause undesirable
sounds.
Here are the usual four
types of noise that comes
out of an inoperative or
failing valve lifter.
Moderate
clicking noise
This noise can be the result
of excessive varnish, wear
on the bottom of the lifter
mat and excessively fast or
slow leak down.
Slow leak down generally
will cause the engine to be
noisy only when cold and
the oil is thick.
With a fast leak down, the
valve train will be noisy
when the engine is warm
and the fast leak down will
also occur if the ball-check
in the lifter fails to seal.
The noise level depends on
the amount of varnish and
the degree of wear.
Loud rapping
sound
A stuck plunger inside the
body of the lifter could be
the reason of the sound and
this is usually due to
excessive varnish between
the plunger and body.
Even the presence of dirt or
other foreign materials
wedged between the
plunger and body causes
such sound.
Another cause of a loud
rapping sound is an
excessively worn base or
foot on the lifter itself.
General valve
train noise
When the sound is
throughout the entire valve
train, the cause is usually
the weight of the oil or the
oil supply itself.
Too much oil in the
crankcase will cause
foaming and aeration as a
result, when air gets into
the lifters, they will fail to
operate properly.
Insufficient oil supply to the
lifters can also cause general
valve train noise and this
could be the result of too
little oil in the crankcase or
clogged main oil gallery
lines.
Excessively thick engine oil
will cause entire valve train
noise when cold-starting an
engine and the noise will
diminish when the oil
warms up and starts to flow
properly.
Intermittent
clicking
This type of noise is hard to
locate as there will be a few
clicks, and then it will be
quiet, but the noise will
reappear after a short period
of time.
The usual cause of
intermittent clicking is a
very minute piece of dirt
that holds the ball check off
the seat for a few seconds
and then passes through.
In rare cases, the cause of
the sound is a pitted or flat
spotted ball-check.
Thank you!
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Get to Know the Different Types of Valve Train Noise