How-to Change Rear Spark Plugs on a 2005 Ford Taurus, with a Duratec Engine,Without Disturbing the Upper Intake Manifold
1. TxGreaseMonkey only recommends tackling this job, if you have a 3/8-in. drive Craftsman 3-piece quick-release extension bar set or equivalent, 3/8-in. universal joint, 3/8-in. drive ratchet, 3/8-in. drive torque wrench (calibrated in inch-pounds), 3/8-in drive 8 mm socket, 5/8-in. spark plug socket with sponge rubber plug holder for a 3/8-in drive ratchet, silicone spray, 10” piece of 3/8-in. I.D. fuel line, Motorcraft Silicone Brake Caliper Grease and Dielectric Compound, Motorcraft AGSF-32W platinum plugs, and a tube of Permatex Anti-Seize Lubricant (133A). High temperature nickel anti-seize compound is even better, but more expensive. Use factory-recommended plugs, since my experience using cross-referenced plugs has not been good. Make sure the engine is “stone cold” before removing any spark plugs or you increase the risk of stripping the threads in the aluminum head.
2. Silicone-spray the sponge rubber plug holder inside the spark plug socket now, so that the newly installed plug will not pull the socket off the extension bar in the spark plug tube later. You don't need to add any more tension to the job, by losing control of anything in the deep spark plug tubes on the backside of the engine. Disconnect the electrical connector to the plug coil on the left rear plug (all work is performed from the passenger side of the engine). Use the 8 mm socket and ratchet to remove the hex-head bolt securing the plug coil. Lift ignition coil pack out; clean with a rag and silicone spray; and apply silicone dielectric compound, using a small screwdriver, to the inside of the spring wire going to the plug. Set the coil pack aside for now.
3. Connect the 6” quick-release extension bar to the spark plug socket. Insert into spark plug tube and seat over plug. “Build-up” the extension by attaching a 3” quick-release extension bar. Next, use a ½” drive 15” flex “T” handle, connected to a ½” x 3/8” socket adapter, and remove the plug. A 3/8-in. drive ratchet may not provide enough leverage to remove the factory-installed plug. Proceed carefully, to prevent stripping the aluminum head.
4. Once again, connect the 6” quick-release extension bar to the spark plug socket. Insert a new, properly gapped plug in socket and apply a half pea-size drop of anti-seize compound to the threads, making sure not to get any on the plug's electrode or porcelain. As the plug is threaded, the compound will coat the threads. If too much anti-seize is applied, you run the risk of coking the plug in the hole, making it very difficult to remove next time. Install the spark plug into the spark plug tube. Rotate the extension bar and seat the plug, being careful not to cross-thread the plug. Once again, “build-up” the extension, by connecting the 3” quick-release extension bar. Using the 3/8” universal joint on top of the 3” extension bar, attach the 3/8-in. drive torque wrench and tighten the plug by applying 84 in.-lbs. of torque. Use the lower end of the torque specs (7 to 14 ft.-lbs.) because anti-seize lubricant increases the actual torque by around 40%. Reinstall the ignition coil pack, electrical connector, and hex-head bolt.