Flipping over the manifold reveals the location of the PCV valve. If you haven't already done so, remove the PCV valve breather screen from the old manifold and slide it into place. Clean and dry the PCV valve grommet. Apply a light layer of silicone to the grommet and then slide it into place over the PCV breather screen. The silicone will prevent the rubber grommet from pulling out during PCV valve servicing.