Chevrolet Sonic Repair Manual: Crankcase Ventilation System Inspection/Diagnosis

Chevrolet Sonic Repair Manual / Powertrain / Engine / Emissions / PCV / 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

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

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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:

Steering Wheel Controls
Some audio steering wheel controls could differ depending on the vehicle's options. Some audio controls can be adjusted at the steering wheel. / (Push to Talk): For vehicles with Bluetooth or OnStar, press to interact with those systems. See Bluetooth (Voice Recognition) or Bluet ...

Engine Oil Change
When a %CHANGE message displays in the DIC, have the engine oil and filter changed within the next 1 000 km/600 mi. If driven under the best conditions, the engine oil life system might not indicate the need for vehicle service for more than a year. The engine oil and filter must be changed ...

Air Inlet Assembly Replacement
Air Inlet Assembly Replacement Callout Component Name Preliminary Procedures Remove the Heater and Air Conditioning Evaporator and Blower Module. Refer to Heater and Air Conditioning Evaporator and Blower Module Removal a ...

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