Note: The operating principle of the PCV system is described in detail in Chapter Engine management and emission control systems.
The PCV system allows crankcase gases to be discharged through a special valve via a hose back into the intake manifold, from where they enter the combustion chambers and are burned off during normal engine operation. In addition to the valve, the system includes a hose leading from the cylinder head cover to the intake manifold and a hose supplying fresh air from the air cleaner under the valve mechanism cover. The PCV valve with the hose connected to it is seated in the cylinder head cover (refer to the accompanying illustrations in Vehicle settings and routine maintenance).
1. With the engine idling and warmed up to normal operating temperature, pull the valve up and remove it together with the connected hose from its seat in the cylinder head cover.
2. Press your finger against the hole in the PCV valve - you should feel a vacuum, otherwise make sure the hose, the fitting on the intake manifold and the valve itself are clear. Replace defective components.
3. Turn off the engine and shake the valve; if it is in good condition, a slight crackling sound should be heard inside the valve. If no sounds are heard, replace the valve.
4. To replace the valve, disconnect it from the hose, try to remember how the connection was organized.
(The article is taken from a web resource: www.toyotaman.ru)
5. When purchasing a new valve, make sure that it matches the size of your car's engine. The best way is to directly compare the new valve with the old one removed from the engine.
6. Connect the new valve to the hose.
7. Check the condition of all rubber hoses and bushings. Replace defective components.
8. Firmly seat the valve in its original place in the cylinder head cover.