The Jaguar S-type is a six-cylinder engine, which means it has two valve covers -- one on the left side of the engine, the other on the right. When changing the valve cover gaskets, do both sides at the same time, as the rubber wears out from the heat and constant movement of the engine. Oil leaking down the side of the engine could be a fire hazard if it builds up, especially if it gets on the exhaust manifold.
Disconnect the negative battery cable, using the appropriate wrench. Set it aside, ensuring that it does not touch metal. Loosen the clamps to remove the air duct using a screwdriver. Unbolt and remove the air cleaner box, using the appropriate socket. If your VIN is between M45255 and N52047, unbolt the power steering fluid reservoir, but leave the lines attached. Move it out of the way.
Remove the ignition coil-on-plug cover, using a screwdriver. Remove the oil level indicator and its tube, using the appropriate socket. Discard the O-ring seal. Move the left engine wiring harness off its brackets on the valve cover and lay it out of the way. Remove the fuel line retaining clip, using a screwdriver. Move the fuel line out of the way. Mark the coil wiring harness connectors, then unplug them. Remove the coils, using the appropriate socket.
Unbolt the valve cover assembly, using the appropriate socket. Lift the valve cover off the engine. If it sticks, tap it with a rubber mallet to break the seal. Discard the gaskets and the retaining bolt O-ring seals.
Clean the valve cover and head gasket-mounting surfaces, using the plastic scraper and rags. Smear a thin layer of RTV silicone on the valve cover gasket-mounting surface. Fit the gasket onto the valve cover. Install new O-ring seals on the retaining bolts. Squeeze a 3mm bead of RTV silicone on the two places where the valve cover meets the head. Install the valve cover and tighten the bolts to 7 foot-pounds of torque.
Reattach the fuel line and wiring harness. Plug in the coils. Install a new O-ring seal on the oil level indicator, then reinstall the indicator. Reinstall the coil-on-plug cover. Reinstall the air cleaner assembly and duct. Leave the battery disconnected.
Remove the ignition coil-on-plug cover, using the appropriate socket. Remove the PCV pipe, using the appropriate socket. Unclip the engine wiring harness and move it out of the way. Mark the coil wiring harness connectors, then unplug the coils. Remove the coils, using the appropriate socket.
Unbolt and remove the valve cover, using the appropriate sockets. If the valve cover doesn't come off easily, tap it with a rubber mallet to break the seal. Clean the valve cover and head gasket-mounting surfaces, using the scraper and rags. Discard the retaining bolt O-rings and the old gasket.
Coat the valve cover mounting-surface with a thin layer of RTV silicone. Fit the gasket to the cover. Place a 3mm bead of RTV where the cover meets the front of the cover. Slide the new O-rings onto the retaining bolts. Bolt the cover on the head, tightening the bolts to 7 foot-pounds of torque.
Reattach the wiring harness to the valve covers. Reinstall the coils and plug them in. Reinstall the PCV pipe. Reattach the negative battery cable.