POSITIVE CRANKCASE
VENTILATION (PCV)
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VALVE
OPERATION: All General Motors gasoline engine
powered vehicles are equipped with Positive
Crank-
case Ventilation-a system which permits no crank-
case emissions
to
be discharged into the atmosphere.
To function properly, the system depends on the
43
PCV Valve which returns blow-by gases to the com-
bustion chamber where they are burned.
MAINTENANCE: This valve must be clean in
order to maintain efficient engine operation.
An
inspection
of
the ventilation filter should be
made at the first oil change
(4
months or
6,000
miles, whichever occurs first). At each subse-
quent oil change, the ventilation filter
should
be inspected and replaced
if
necessary.
Re-
place filter at least every
24,000
miles. Under
normal driving conditions, the
PCV
Valve should
be
replaced every
24
months or
24,000
miles,
whichever occurs first, and
all hoses and fit·
tings
should be inspected and cleaned
or
re-
placed,
as
necessary. Replace the
PCV
Valve
and inspect related parts every
12
months
or
12,000 miles when the vehicle is used in a ser-
vice requiring more frequent engine oil change
as
covered on page
53.
NOTE: Emission control systems in this section are Illustrated
on
V-8
engines; systems on 4 and 6 cylinder engines are similar.
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