It is certainly possible to replace the PCV valve on many engines on a DIY basis, and the procedure is no more complicated than disconnecting the hose leading from the valve to the intake system, removing the old valve from the valve cover, and pushing the new valve into position. Of course, you also need to reconnect the hose using a new hose clamp.
However, the above is the short version of the PCV valve replacement procedure, since it assumes that the rubber grommet in the valve cover that holds the PCV valve in position and the rubber hose leading to the intake system are both in good condition. Thus, there is a longer version of the procedure, which comes into play when neither the grommet nor the hose can or should be used again.
In these cases, it may be necessary to use some force to dislodge the hardened grommet from the valve cover, with the most common method being using a small or medium flat screwdriver to lever or pry the grommet out of its hole. Be aware though, that this can be a time-consuming process, and that it could potentially cause the hardened rubber grommet to fragment, which could cause pieces of rubber to fall into the engine, where it could potentially interfere with some valve train components.
In the case of hardened, split, or degrade rubber hoses, it could potentially be very difficult to disconnect the hose from the intake system, since working space on some engines is severely limited. Note also that it is not wise to replace the rubber hose with a jerry-rigged hose- even if you are going to use oil-resistant tubing. This type of replacement hose will harden very quickly in this application, thereby guaranteeing the creation of vacuum leaks not long after the replacement.
To prevent this from happening, it is imperative that this particular rubber hose is replaced only with the preformed OEM part, which is made of a rubber compound that is, and will remain, highly resistant to hardening and degradation for many years.
Be aware though, that is it extremely difficult to access the PCV valve and its associated hose(s) on some engines, and therefore, we do not recommend that novice non-professional mechanics attempt the replacement of the PCV valve on these engines. In many of these cases, it is necessary to remove or partly disassemble various unrelated engine components just to gain easy access to the PCV valve, which greatly increases the possibility that some components might suffer damage or even destruction in the process of removal or disassembly.
Thus, if you are not comfortable with the idea of removing or disassembling major engine components, we highly recommend that you seek professional assistance with the process of diagnosing and replacing a suspect PCV valve. We also recommend that you approach several workshops near you for repair estimates that include all relevant charges to ensure you get the most value for your money.