Positive Crankcase Ventilation (PCV) system


1. The Positive Crankcase Ventilation (PCV) system reduces hydrocarbon emissions by scavenging crankcase vapors and burning them along with the air-fuel mixture.

2. The PCV system uses a PCV orifice (6.0L models) or a PCV valve (non-6.0L models), which are threaded into either the rear of the left valve cover (4.3L V6) or below the throttle body in the intake manifold (5.3L and 6.2L V8). There are two hoses in this system. The fresh air inlet hose carries outside air from the air intake duct to a pipe on the right valve cover, then into the crankcase, where it mixes with blow-by gases and crankcase vapors. These vapors are drawn from the crankcase through the orifice or valve, through the crankcase ventilation hose (PCV hose), then into the intake manifold, where they mix with incoming air.


Note: This procedure does not apply to 6.0L V8 models. On 6.0L V8 models, the orifice is part of the driver’s-side valve cover and is not serviceable separately. If the orifice becomes clogged, the valve cover must be removed to clean the orifice out.

3. On 4.3L V6 models, remove the driver’s- side engine cover.

4. On models with 5.3L and 6.2L V8 engines, remove the intake air duct (see Air intake duct and air filter housing — removal and installation).

5. Disconnect the hose from the PCV valve (see illustration).

17.5 Disconnect the hose from the PCV valve (V6 shown)

Chevrolet Silverado Emissions and engine control systems _ Disconnect the hose from the PCV valve (V6 shown)

6. Use a socket to unscrew the PCV valve from the engine.

7. To install, reverse the removal procedures.

  • Pages

    open all | close all