PCV Valve's Function

• The PCV valve is a part of the 1998 Explorer's emission control system. This valve opens as the engine speed increases, allowing toxic gases from the crankcase to enter the combustion chamber for burning. This burning keeps the gases from reaching the atmosphere.
  
  

Locating the PCV Valve

• Ford installed the PCV valve on the 1998 Explorer's 4.0-liter SOHC engine in the top-rear of the driver's side valve cover. It has a 1/2-inch rubber vacuum line plugging into the top of it.
  
  

Removing the PCV Valve

• Grasp the 1998 Explorer's PCV valve with your hand and pull it upward with a slight twisting motion to remove it from the valve cover. Hold the 1/2-inch vacuum hose on top of the PCV valve and pull the PCV valve from the hose, using a slight twisting motion.
  
  

Installing the PCV Valve

• Line the base of the PCV valve up with rubber grommet in the 1998 Explorer's driver's side valve cover and press the PCV valve into the rubber grommet until the valve stops moving. Press the 1/2-inch rubber hose onto the top of the PCV valve.