Lincoln released the LS in the 2000 model year as an attempt to infiltrate the midsize luxury car market. The LS was a short-lived project, as it only lasted through the 2006 model year. The 2005 Lincoln LS came standard with a 232-horsepower, 3.0-liter V-6 engine. This engine was of the high-tech variety and required extensive labor to get to the spark plugs, making replacing the spark plugs a job only for a do-it-yourself mechanic with plenty of experience.
Install a memory saver according to the memory saver’s instructions. Remove the negative battery cable from the battery, using a combination wrench.
Lift the front of the LS with a floor jack and slide jack stands under its frame rails. Lower the vehicle onto the frame rails.
Allow the vehicle to sit until the engine is cool to the touch. Unscrew the cap from the radiator degas bottle. Position a drain pan under the radiator petcock and turn the petcock counterclockwise to start the flow of coolant. Close the petcock once the flow of coolant stops.
Raise the LS, remove the jack stands and lower the car to the ground.
Pull the crankcase ventilation tube and fuel vapor tube from the air filter outlet tube and set them aside. Loosen the two air filter outlet tube's hose clamps with a ratchet and socket, and remove the tube from the engine compartment.
Lift each wiper blade off the windshield and place a strip of masking tape under the wipers. Lower the wipers to the masking tape, then trace along each wiper blade with a pen, leaving an alignment mark on the masking tape.
Pry the wiper arm-retaining nut covers from each wiper arm, using a flat-head screwdriver. Remove the wiper arms’ retaining nuts, using a ratchet and socket. Pull the wiper arms from the vehicle.
Remove the six pin-style retaining clips from the windshield cowl by prying them off with a flat-head screwdriver. Lift upward on the cowl to release its retaining clips and remove it from the vehicle.
Unfasten the seven bolts securing the engine crossover brace to the vehicle, using a ratchet and socket, then pull the brace from the vehicle.
Unplug the throttle position sensor and electronic throttle control -- the two electrical components on the throttle body – wiring harnesses from their receptacles.
Pull the brake booster vacuum hose – the large vacuum hose directly behind the throttle body – from its inlet on the intake manifold. Pull the evaporative emissions hose – the hose behind where the brake booster hose was – from the intake manifold. Pull the PCV tube from the front, passenger’s side of the intake manifold, then from the PCV valve, which is on the driver’s side valve cover.
Find the two coolant hoses on the front passenger’s side of the intake manifold. Slide the hose clamps 3 inches down the hoses, using slip-joint pliers, then pull the hoses from the manifold with a slight twisting motion.
Pry the PCV tube and coolant hose routing clip from the intake manifold, using a flat-head screwdriver. Position the PCV tube and coolant hose, which several plastic retainers hold together, aside and out of the way of the intake manifold.
Remove the front manifold bracket-to-intake manifold bolt, which is on the front passenger’s side of the intake manifold, using a ratchet and socket.
Unplug the two intake manifold tuning valve connectors from the IMT valves on the rear passenger’s side of the intake manifold. Disconnect the fuel pressure sensor wiring harness, which is on the rear driver’s side of the upper intake manifold. Pull the fuel pressure sensor vacuum hose -- the hose next to the pressure sensor’s wiring harness -- from the intake manifold.
Unfasten the passenger’s side manifold support brace-to-intake manifold bolt, which is on the lower passenger’s side of the intake manifold, using a ratchet and socket. Remove the four upper intake manifold-to-lower intake manifold bolts. Lift the upper intake manifold from the lower intake manifold and remove it from the engine compartment.
Pull the upper intake manifold gasket from the engine and put a clean shop cloth over the inlets into the lower intake manifold to prevent debris from getting into the engine. With the intake manifold removed, you have a clear view of all six coil packs.
Check the gap on all six new Motorcraft AGSF-32FS spark plugs using a spark plug gap tool. The 3.0-liter engine requires a gap from 0.051 to 0.057 inches. Exchange any incorrectly gapped plugs for new ones, as these plugs are not adjustable.
Unplug the wiring harnesses from all six ignition coils. Remove the bolt securing each ignition coil to the engine, using a ratchet and socket, then pull each ignition coil from the engine with a slight twisting motion, exposing the six spark plugs.
Remove all six spark plugs with a ratchet, 6-inch extension and spark plug socket.
Hand-thread the replacement plugs into the engine using the 6-inch extension and spark plug socket. Tighten the spark plugs to 11 foot-pounds with a torque wrench.
Apply a dab of dielectric grease inside the boot on the base of each coil pack and spread the grease around the inside of the boot with a small flat-head screwdriver. Guide the coil packs into the spark plug tubes and press them downward until each one clicks on its respective spark plug – you can install any coil pack on any plug. Tighten the coil packs’ retaining bolts to 44 inch-pounds with an inch-pound torque wrench and socket.
Plug the wiring harnesses into their respective coil packs. Each wire routes only to one coil pack to prevent incorrect connection.
Set a new upper intake manifold gasket into place and set the upper intake manifold onto the lower intake manifold. Hand-thread the upper intake manifold-to-lower intake manifold bolts.
Number the upper intake manifold-to-lower intake manifold bolts, starting from the front-most bolt and working counterclockwise around the intake manifold, 1 through 6.Tighten the bolts to 89 inch-pounds in the following order: No. 3, No. 4, No. 1, No. 6, No. 2, No. 5.
Install the passenger’s side manifold support brace-to-intake manifold bolt and tighten it to 89 inch-pounds. Plug the three wiring harnesses – two IMT valve and fuel pressure sensors – to the rear of the intake manifold. Plug the fuel pressure sensor vacuum hose to its inlet on the rear of the intake manifold.
Thread the front manifold bracket-to-intake manifold bolt by hand and tighten it to 89 inch-pounds. Route the PCV tube and coolant hose in the direction they were before you positioned them aside. Plug the PCV tube into the PCV valve on the driver’s side valve cover. Press the PCV tube and coolant hose retaining bracket into its recess in the intake manifold.
Plug the two coolant hoses into their respective inlets on the upper intake manifold and slide the hose clamps to within 1/2-inch of each hose’s end. Press the evaporative emissions hose and PCV tube into their respective inlets on the intake manifold. Plug the brake booster vacuum hose into its inlet directly behind the throttle body.
Connect the throttle position sensor and electronic throttle control wiring harnesses into their receptacles on the throttle body -- they are different sizes to prevent incorrect connection.
Reinstall the engine crossover brace and tighten its seven retaining bolts to 15 foot-pounds.
Lower the rearmost part of the windshield cowl so its locator pins slide into the locator holes in the car's body. Press the front of the cowl downward to snap its retaining clips into place. Press the six pin-style cowl retaining clips into place to secure the cowl.
Sit the wiper arms onto the wiper motor output shafts loosely and pivot the arms until the wiper blades align with the lines on the masking tape. Press the arms downward onto the output shafts and torque their retaining nuts to 18 foot-pounds. Lift the wiper blades and remove the tape.
Press the air filter outlet tube onto the outlet on the air filter box and the inlet on the throttle body. Tighten its two hose clamps to 35 inch-pounds. Press the fuel vapor tube and crankcase vent tube into their respective inlets on the air filter outlet tube.
Install the negative battery cable to the negative battery terminal, then tighten its retaining bolt to 62 inch-pounds. Remove the memory saver from the vehicle.
Pour about half of each gallon of Motorcraft Premium Gold Engine Coolant, or an equivalent coolant meeting specification No. WSS-M97B51, into the two clean 1-gallon sealable containers. This creates four half-full gallons of coolant. Fill the four half-full gallons of coolant the rest of the way with clean water. Tighten the caps onto all of the containers and lightly shake them to mix the water and coolant.
Open the air bleed valve in front of the throttle body, using a flat-head screwdriver. Open the heater air bled valve, which is on the rear driver’s side of the engine compartment, near the master cylinder, using a flat-head screwdriver.
Fill the degas bottle to the top of its filler neck with the coolant and water mixture and wait to allow the coolant level to stabilize. Repeat this step until coolant flows from the air bleed valve, then tighten the air bleed valve. Tighten the cap on the degas bottle.
Start the engine and turn the heater to its highest temperature and fan speed settings. Once coolant flows from the heater air bleed valve, tighten it with a flat-head screwdriver. Let the engine idle for five minutes, remove the cap from the degas bottle and refill the coolant level to the “Cold Fill Max” mark on the degas bottle with your coolant and water mixture each time the level drops .
Open the heater air bleed valve one more time with a flat-head screwdriver to release any additional air, and close it again.
Increase the engine speed to about 1,500 rpm and hold it there until hot air comes from the heater vents. Let the engine speed reduce to an idle and verify that hot air continues coming from the heater vents. If there is no hot air at idle, shut the engine off, let it cool, then restart the process from Step 2.
Set the temperature to 75 degrees Fahrenheit and leave the vehicle idling for about two minutes. Shut the engine off and let the vehicle sit until the engine is cool to the touch. Once cool, remove the degas bottle’s cap and refill the degas bottle to the “Cold Fill Max” mark. The LS’ cooling system requires a total of 2.8 gallons to refill it, but the exact amount your LS requires may vary.
