Thursday, May 26, 2011

1999 Lincoln Navigator 32v 5.4L spark plug change

The 99 Lincoln Navigator with 5.4l 32v engine was my most difficult spark plug change that I have done to date. I am going to list the steps here for anyone that might want to try this themselves. This is a task not for the faint of heart. I would  rate this job a 7 (10 being most difficult) on the difficulty scale. Here are the steps that I performed (you may have different steps):
  1. With the engine running, turn the steering wheel hard right. This will be self-explanatory in the later steps. Turn engine off and allow to cool several hours.
After engine has cooled, I started on the left bank (driver's side of engine). Here is numbers 5-8 cylinders, no. 5 at the front of the engine and no. 8 at the rear and the most difficult side to deal with. Remove the 10mm nut from the power steering reservoir that is attached to the intake plenum. With this 1 nut removed I was able to pull back on the reservoir and gain clearance. Some instructions say to remove the reservoir entirely, I didn't have to. Next, unplug the wires from the EGR solenoid and the EGR feed back sensor (the square sensor with the two hoses attached)then remove these two hoses. Note that one hose is larger than the other. Remove the brake booster vacuum line and place out of the way. Note the EGR tube going across the valve cover at the rear of engine. Remove the oil dipstick.
  1. After positioning wires and hoses out of the way, get a 1¼ inch open end wrench. Slide under the vehicle at the rear of the left front tire that has been turned hard right. Locate the left side exhaust manifold, at the rear of the manifold you will see a 1¼ nut holding the EGR tube to the exhaust manifold. Using the wrench, remove this nut from the manifold completely. Now back to the top side of the engine, using a screw driver or other pry tool, get between the valve cover and the EGR tube and pry up gently (remembering the valve cover is plastic, don't pry too hard or valve cover damage will occur). I was able to use my hand to pull up on the tube enough to clear everything. I have read the removal of the EGR tube nut is not necessary, in my case it was. I couldn't get the no. 8 coil off the plug. With the EGR tube nut removed, and a little clearance by pulling up on the tube, the coil came right off. I am getting ahead of myself here.
  2. Using a 13mm socket, remove the two bolts that hold the coil cover in the middle of the valve cover. With this cover removed, the 4 coils are exposed. Note the wiring harness on the coils - the harness is shaped like the cover and must placed back in the proper place. Unplug the wires from the coils by pressing on the tab at wire end of the plug. Repeat this process for all 4 coils. Using various extensions and a swivel with a 5/8" spark plug socket remove the spark plugs. After installing all 4 new plugs and coils, pull the wires on each coil to be sure the wires are securely plugged on the coils. Now for the famous words "Reverse procedure". There are a couple of points of interest - On the EGR tube when re-installing the nut, I was able to hook a finger on the small hose tube (remember the hoses I disconnected on the EGR feedback sensor) and pull down while I started the nut. When installing the hoses on the EGR feedback sensor, notice on the sensor itself there is a large and small connector for the hoses - large hose goes on large connector, small hose goes on small connector.
  3. We are at the right side of the engine. Start by removing the battery. Remove the starter solenoid by removing two 8mm bolts that hold the solenoid to the firewall. It isn't necessary to remove any wires from the solenoid. Remove the wiring junction box under the solenoid by removing two 8mm bolts, unplug the single wire on top of the junction box and move the solenoid and junction box to the right fender as far as possible without stretching or pulling any wires. Remove the transmission dipstick.
  4. At this point, I read to drain the coolant and disconnect the upper radiator hose and remove the heater hoses. I didn't do this step, I found it was not needed in my case. Using the 13mm socket, remove the coil cover in the middle of the valve cover exposing the coils and the rest is like the left side. There is no EGR tube to contend with on the right side. I had more clearance on the right side than the left side. The right side cylinders are numbers 1 - 4, no. 1 at the front of engine and no. 4 at the rear.
This job took about 2 hours from start to finish. Everything went fairly well, except starting the nut on the EGR tube. It wanted to be contrary, but finally started.
I personally don't see how anyone could do this with the engine hot as you will get "up close and personal" with the motor before you complete this job.


  1. Thank you Danny, this has been very useful.

  2. I am having a hard time getting the spark plug out of the hole. It is loose and ready to come out but I can't find anything long and thin enough to get it out. I tried a magnet n that didn't work either. Help!!!!!