Camaro V8-5.7L VIN G (1998)
Positive Crankcase Ventilation: Description and Operation
Description - System Routing
DESCRIPTION
A closed crankcase ventilation system is used to provide a more complete scavenging of crankcase vapors. Fresh air from the throttle body is
supplied to the crankcase, mixed with blow-by gases and then passed through a crankcase ventilation valve into the intake manifold.
OPERATION
The primary control is through the crankcase ventilation valve which meters the flow at a rate depending on manifold vacuum. To maintain idle
quality, the crankcase ventilation valve restricts the flow when intake manifold vacuum is high. If abnormal operating conditions arise, the system
is designed to allow excessive amounts of blow-by gases to back flow through the crankcase vent tube into the engine air inlet to be consumed by
normal combustion.
The engine ventilation system was developed to minimize oil consumption and ensure that oil ingestion could not occur during vehicle limit
handling maneuverers. Filtered fresh air is routed from up stream of the throttle blade to the front of the right rocker cover via a formed rubber
hose. To reduce the potential of oil pullover into the throttle bore area due to back flow of the ventilation system, the fitting in the right side rocker
cover is located between a shield from the rocker arms. Blowby gases are routed from the rear of both rocker covers, through molded nylon lines
to a tee fitting located on the centerline of the engine at the rear of the intake manifold. From there, a single nylon line carries the foul air gases
through an externally mounted, horizontal PCV valve and enters the intake manifold behind the throttle body.
