The 1994 VW Jetta PCV valve is located on the outside of the air cleaner housing. You can find the valve on the back side of the housing.
The PCV valve on a 2002 Volkswagen Jetta 2.0 liter is located on the end of the rocker arm cover. It has one hose attached to it.
The pcv vavle is built in through the valve cover, so not an actual pcv vavle you would see on an average car, if it starts going bad your idle is going to go haywire, an occasional loud squealing, you have to replace the valve cover, which is 136.00. (PCV-Positive Crankcase Venalation
Take a look at the following Flickr photo. This is a '97, but the PCV is located in the same spot on the '98. http://www.flickr.com/photos/roy_vanegas/2921211470/in/set-72157607808188158/
04 chevy 6.0 2500hd
Pull upward on the hose that the PCV valve is in. The PCV valve will pull out of the hose. The PCV valve is located in the valve cover.
Disconnect the PCV valve tube from the PCV valve.Disconnect the PCV valve electrical connector if it has one.Turn the PCV valve counterclockwise to remove from the valve cover.To install, reverse the removal procedure.
Remove the PCV valve retaining screws. Remove the PCV valve hose. Reverse the process to install the new PCV valve.
The PCV valve has a check ball in it, That's what you are hearing. REPLACE PCV VALVE
I guss the old way spray a little carb cleaner in it and shake it.
The PCV valve is located in the valve cover
The pcv valve is on the passenger side valve cover