The PCV (positive crankcase ventilation) valve is a tiny vacuum-operated valve that's an integral part of your emissions system. The 1998 Honda Civic has the valve, like all modern cars. The valve may require replacement from time to time, but it cannot be repaired. Fortunately, a replacement PCV valve usually costs less than $10 and the piece takes less than 10 minutes to install.
Shut off the Civic's engine and put on a pair of gloves. Open the hood.
Find the rubber hose protruding from the center of the valve cover's front edge. The valve cover is the object in the center of the engine compartment that houses the spark plugs.
Trace the hose downward onto the intake manifold. Use your pliers to pinch the clamp around the end of the hose, and then unplug the end of the hose attached to the manifold. Now you'll see the small PCV valve.
Pull the PCV valve straight out. If it doesn't come out easily, use your pliers for additional leverage. Shake the PCV valve. If you hear what sounds like a ball bearing moving around inside the PCV valve, you probably don't need to replace the PCV valve. If you hear nothing, replace the valve.
Insert the new PCV valve into the mounting port. Squeeze the clamp on the hose and attach the hose to the end of the PCV valve. Close the hood.
