8.2. System of the operated ventilation of a case (PCV) - the general information, check of a state and replacement of components

General information

The PCV system which is included in the obligatory package of engines of all models considered in the present manual serves for decrease in issue in the atmosphere of hydrocarbonic connections at the expense of a conclusion from the engine of crankcase gases. The purge of the block is carried out by a pro-race of the fresh air arriving from the air cleaner through a case in which it mixes up with the collected evaporations and the gases which broke from combustion chambers and is removed via the PCV valve in the inlet pipeline. The principle of functioning of system of the operated ventilation of a case is presented on an illustration.

The PCV valve, air inlet and set of the hoses connecting the listed devices to the engine are among the main components of system.

For the purpose of maintenance of stability of turns of idling the PCV valve blocks a purge stream at deep depression in the inlet pipeline, the failure of the valve can lead to unexpected stops of the engine and sharp jumps of turns.

Violation of serviceability of functioning of system of ventilation can lead a case to violation to stability/decrease in turns of idling, up to a spontaneous stop of the engine, to development of leak of oil, formation of a tarry raid on the internal surfaces of the unit.

Check of serviceability of functioning of the PCV valve


1. Disconnect a ventilating hose from the PCV valve. Remove the valve from the engine (turn out it or take from the landing plug in a cover of a head of cylinders). After removal of the valve connect to it a ventilating hose again.

2. Start the engine on single turns and press a finger to an opening in the valve, - in assembly depression has to take place.

3. If depression is not felt, at first check passability of a hose, then (if a hose as it should be), kill the engine, release the valve from a hose and by means of a thin core check freedom of the course of its plunger, - the core is entered into an opening with the equipped carving of the party of assembly.

When stirring the serviceable valve has to publish a crash.

4. In case of need make replacement of valvate assembly.



1. Turn out the valve from the nest in a cover of a head of cylinders, or having pulled vertically up, take it from the rubber landing plug. Estimate a plug condition, in case of need make replacement.
2. If the valve is hammered with tarry deposits, also the probability of violation of passability of a connecting hose is not excluded, - remove a hose and wash out it solvent.
3. Having washed out a hose, check it for existence of signs of aging of material and mechanical damages. Track reliability of fixing of a hose on reception unions.
4. In case of need make replacement of the PCV valve.