Positive Crankcase Ventilation: Description and Operation

Crankcase Ventilation System Description

The compressed combustion gas which escapes past the piston rings into the crankcase is known as blow-by gas. Blow-by gas contains large amounts of carbon monoxide (CO) and hydocarbon (HC). The positive crankcase ventilation (PCV) system prevents the blow-by gas from being emitted into the atmosphere. The PCV system routes the crankcase blow-by gas back into the intake system where the blow-by gas becomes part of the combustion process.

Results Of Incorrect Operation

A plugged oil separator or hose may cause any of the following conditions:

* A rough engine idle
* Engine stalling or low engine idle speed
* High engine crankcase pressure
* Engine oil leaks
* Engine oil in the air cleaner
* Oil sludge in the engine
* Engine oil consumption
* Excessive exhaust emissions

A faulty separator or hose may cause any of the following conditions:

* A rough engine idle
* Engine stalling
* High engine idle speed
* Incorrect engine crankcase pressure
* Excessive exhaust emissions
* Engine oil consumption