Buick Regal: Crankcase Ventilation System Description
General Description
A crankcase ventilation system is used to consume crankcase vapors in the combustion process instead of venting them to atmosphere. Fresh air from the intake system is supplied to the crankcase, mixed with blow by gases and then passed through a calibrated orifice into the intake manifold.
Operation
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The primary control is through the positive crankcase ventilation (PCV) valve (2) which meters the flow at a rate depending on intake manifold vacuum. The PCV valve is an integral part of the camshaft cover. Fresh air is introduced to the engine through PVC (1) under normal operating conditions. If abnormal operating conditions occur, the system is designed to allow excessive amounts of blow by gases to back flow through the crankcase vent valve (3) into the intake system to be consumed by normal combustion.
Only on turbocharged engines, there is a one way valve (2) in the camshaft cover in order to prevent the crankcase from being pressurized by positive pressure in the intake manifold when the turbocharger is in operation. When the turbocharger is operational, the pressure in the intake manifold can exceed atmospheric pressure which, without the one way valve, would force oil and PCV gases out of the camshaft cover and into the induction system, via the hose to the camshaft cover. This can cause coking of the throttle body and induction system, and can reduce the efficiency of both combustion and the intercooler system, in normal operation the PCV gases are drawn into the air stream post intercooler (6). However, when the turbo is spooled up the turbo can become the vacuum source for the vent system.
PVC#4 controls the max. flow so the crankcase stays at a normal vacuum during normal operating conditions.
Results of Incorrect Operation
A plugged orifice may cause the following conditions:
- Rough idle
- Stalling or slow idle speed
- Oil leaks
- Sludge in engine
A leaking orifice may cause the following conditions:
- Rough idle
- Stalling
- High idle speed
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Engine Component Description
Engine Description
Cylinder Block
The cylinder block is constructed of aluminum alloy by precision
sand-casting. The block has 5 crankshaft bearings
with the thrust bearing located on the second bear
Use of Room Temperature Vulcanizing (RTV) and Anaerobic Sealant
Cleaning Mating Part Surfaces for RTV Joints
RTV sealant depends greatly on adhesion to the mating parts in order to form
and maintain a robust sealed joint. As
with any adhesion system, proper surfa
Special Tools and Equipment
SPECIAL TOOLS
DT-45866
J-45866
Input Shaft Seal Installer
EN-8062
J-8062
KM-348
Valve Spring Compressor - Head Off
EN-8087
J-8087
Cylinder Bore Gauge
EN-21867-850
J-21867-850
KM-498-B
KM-6106
83 93
SEE MORE:
DTC C0242
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptor
DT
DTC B0550
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure:Diagnostic System
Check - Vehicle
Review the description of Strategy Based Diagnosis:Strategy Based
Diagnosis
An overview of each diagnostic category can be found here:Diagnostic
Procedure
