Instructions for Replacing the PCV Valve

A brief introduction to understand the utility of the PCV (Positive Crankcase Ventilation) valve: it was introduced to reintroduce the vapors generated by the blow-by phenomenon into the combustion chamber, injecting them into the intake ducts, usually taken from the valve cover, but also directly from the engine block.

Blow-by literally means "blowing through" and is the phenomenon that occurs when gases in the combustion chamber are at maximum pressure and some of them pass through the piston rings, reaching the lower part of the engine block.

This phenomenon leads to an increase in pressure under the piston dome and throughout the engine block. The main problem with blow-by is the increase in pressure under the piston dome, creating an obstacle during the descent of the piston, with pressure values rising to the point of potentially stalling the engine: hence the need to vent these excess gases.

Initially, the pressure was released into the air, but the major issue is that the gases, passing through the oil, are rich in hydrocarbons and therefore very polluting. The pollution generated by blow-by has led all manufacturers to the same solution: reintroducing the vapors into the combustion chamber using a specific valve: the PCV valve, which can manage the vapor intake based on the pressure in the engine block and the engine load.

With this introduction, the importance of keeping the PCV valve clean and efficient is understood, and when necessary, replacing it along with the related ducts (if using old ones, clean them well): being made of hard plastic, simply heat them with a heat gun to fit perfectly into their respective seats.