Chevrolet Sonic Repair Manual: Crankcase Ventilation System Inspection/Diagnosis
- Results of Incorrect Operation
-
A plugged positive crankcase ventilation (PCV) orifice or hose may cause the following conditions:
- Rough idle
- Stalling or slow idle speed
- Oil leaks
- Oil in the throttle body
- Sludge in the engine
- Functional Check
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With these systems, any blow-by in excess of the system capacity, from a badly worn engine, sustained heavy load, etc., is exhausted into the throttle body and is drawn into the engine.
Proper operation of the crankcase ventilation system depends upon a sealed engine. If oil slugging or dilution is noted and the crankcase ventilation system is functioning properly, check the engine for a possible cause. Correct any problems.
If an engine is idling rough, inspect for a clogged PCV orifice, a dirty vent filter, air cleaner element, or plugged hose. Replace as required. Use the following procedure:
- Remove the PCV hose from the cylinder head cover.
- Operate the engine at idle.
- Place your thumb over the end of the hose in order to check for a vacuum. If there is no vacuum at the hose, inspect for the following items:
- Plugged hoses
- The manifold port
- Turn OFF the engine.
- Inspect the PCV orifice in the cylinder head cover for debris or blockage.
PCV
...
Positive Crankcase Ventilation Hose/Pipe/Tube Replacement
Removal Procedure
Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct
Replacement.
Open the 2 positive crankcase ventilation pipe retainer clips ...
Other materials:
Front Lower Grille Replacement
Front Lower Grille Replacement
Callout
Component Name
Preliminary Procedures
Remove the front bumper fascia assembly. Refer to Front Bumper Fascia
Replacement.
Remove the front bumper fascia energy absorber. Refer to Fron ...
Engine Coolant Fan Shroud Replacement (LDE LUW)
Engine Coolant Fan Shroud Replacement
Callout
Component Name
Preliminary Procedure
Remove the radiator surge tank. Refer to Radiator Surge Tank Replacement.
Unclip transmission cooler lines from shroud if equipped.
Un ...
Crankshaft Rear Oil Seal Replacement
Special Tools
EN-658 Rear Main Seal Installer
For equivalent regional tools, refer to Special Tools.
Removal Procedure
If equipped with automatic transmission, remove the flex plate. Refer
to Automatic Transmission Flex Plate Replacement.
If equipped with a manual transmis ...
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