Time to dress up the under the hood? Are you done adding all the bling that you can attach with sticky tape? If so, then it is time to add some Aluminum valve covers to the 4.6L.
The valve covers arrive boxed and packages neatly and securely, complete with new seals and gaskets. The really nice thing about these covers, they have a seal groove machined on the mating surface for the gasket to seat into. This makes installing the covers so much easier because it prevent the gaskets from moving around and creating an improper seal with the heads. The new rubber gaskets that came with our application had moved around a little in the packaging, so we installed them into the heads the night before so that they lost any of their memory of packaging and inherited the shape of the valve seal channel before installation.
The 2002 application that we have, requires a 99-01 oil filler cap to be used. This is a screw in cap that ratchets once tight. We went to a local "Pick a Part" and bought one for $1.06 from a wrecked Windstar, there are probably many applications that will cross over and can be used for the Mustang. A Ranger or Taurus would probably work just fine as well.
Removing the existing plastic valve covers in our application was a little easier that you will probably experience because we had the upper intake completely removed. This allows for a significant amount of room for manipulation and movement to remove the existing covers.
Our application already had the intake chamber and throttle body removed. The wiring harness for the injectors is the biggest pain that you will have to deal with. Tie this up and out of the way as much as possible. In order to do this, detach the connections to the coil packs and the injectors. The wiring harness will be secured to several of the valve cover studs with plastic retainers. You will need to pry this off with a suitable screwdriver or a similar pry bar device.
There will be 11 bolts/studs that hold the stock valve covers to the head. You will need various lengths of extensions, a universal or swivel joint and both deep and regular sockets to make your life easier. With a combination of these options, getting to the hard to reach studs/bolts really isn't difficult, finding the correct access route to them is really the only challenge.
The drivers side is going to be the most difficult installation, you can either save the easiest for last or learn the tricks on the easiest one first. We chose the passenger side first strictly because that was the side I was on when we started. The most difficult retainers to reach are hidden right next to the shock tower and the one at the outside rear of the motor. A regular socket and swivel will get you there, but you are going to have to work around the AC hose routing and pipe-works for both of these.
With all of the retainers removed, you can loosen the seal between the head and the stock valve covers. Remember, these are plastic, pry up very gently in the front corner and the seal will easily start to open up. Once the whole valve cover seal has been broken, you will be able to remove the cover. Do this by rotating the cover from the outside toward the center of the motor, this motion will help to clear the over head cams protected by the covers. Some jockeying back and forth and different wiggles with easily help to remove the valve cover. If you haven't removed the intake system, you will have to deal with a throttle body and fuel rails. This will definitely make removal more difficult but the same technique will be required. With the electrical wires up and out of the way, you should be able to get enough clearance.
Once the cover has been removed, you need to clean off the seal surface on the head. There is two gobs of RTV sealant where the front timing cover meets with the heads. Clean this off carefully with a dull scraper. Remember, these are Aluminum heads and you can easily mar the surface if you are not careful. Clean the rest of the surface off with a towel and some carburetor cleaning fluid. This is where the rubber gasket mates with the heads and it is really important that it is clean and free of remnant sealant.