04 Xterra Can Not Remove Lower Intake Manifold
With a lot of forum posts dropping like flies due to Photobucket's new policies, a new How-to needed to be posted for changing out spark plugs on your newer model Xterra, Frontier, or Pathfinder. Preliminary acknowledgements go to rouguebuck on TNX who had the most complete write-up I found.
First and foremost, you can do this. It will take about 1-3 hours depending on your beverage intake and your mechanical knowledge. I recommend having the right tools for the job (and not living in hotter'n heck Abalama).
Before we get started, I want to note that I started on the passenger side since this side requires the removal of the intake plenum and I knew it would take significantly more energy than the driver side.
I was not wrong.
Parts Required:
-Spark Plugs (I used NGK Iridium LFR5AIX-11) (6x)
-Dielectric Grease
-Upper Intake/Plenum Gaskets (Set of 3x)
-Engine Oil (opt.)
Tools I Used:
-Phillips head screwdriver
-Flat head screwdriver
-12mm box wrench
-10mm box wrench
-1/4" socket wrench
-3/8" socket wrench
-10mm deepwell socket
-12mm socket (and/or deepwell)
-5/8" [16mm] spark plug socket (or similar, standard deepwell)
-9" of extensions for 3/8" socket wrench
-Needle-nose pliers
1) Locate your engine and remove the pretty stuff.
You can do this, right? Yours may not look like this one because of the K&N intake. Remove the two 12mm bolts on the "V6 4.0" cover Remove the two bolts connecting your intake tube-to-air cleaner box to the "V6 4.0" cover. Gently pry up the cover. They're on pretty snug, but aren't retained like the stupid pop-rivets that hold on trim, so don't be afraid to pry. Prying from the passenger side first was a little easier.
Also, loosen the hose clamp(s) that connect the air tube to the throttle body and separate the two. This can be done with a screwdriver or a 10mm.
Oh, and remove the negative side of the battery unless you gangsta. I'd rather you not fry yourself or anything else. I don't like the zap-zaps.
Figure 1. The Engine Bay
2) Remove vacuum connector and the canister.
This little canister needs to removed for a later step. Remove the two-pin, gray connector. Then remove the two bolted components. The canister is mounted with a 12mm and the adjacent bracket has a 10mm.
Also, start keeping a count of the number of electrical connections and number of hoses you disconnect. This will make it easier to remember at the end.
Figure 2a. Vacuum Electrical Connector
Figure 2b. Vacuum Bolts (Top is 12mm, Bottom is 10mm)
3) Removing electrical connectors and hoses from the throttle body.
Start by removing the larger connector located on the right of the throttle body.
Figure 3a. Throttle Body Electrical Connector
Then remove the hose that goes up and over the throttle body. NOW, the FSM wants the mechanic to drain the coolant from the engine prior to starting. If you're following that manual and this DIY, remove the hose connected to the bottom of the throttle body as well. OTHERWISE, DO NOT REMOVE THE LOWER HOSE. Now is not the time to be thinking, "screw what the guy with the pony picture says." I did not remove the hose.
Figure 3b. Hoses Leading to Throttle Body.
4) Remove electrical connectors and hoses from the intake.
This is where the pain begins. Embrace it. You love your truck. You love your truck. You love your truck… at least you think so, right?
There are 2 hoses, 1 electrical connector, and 3 conduit retaining pop-rivets connected to the back of the intake. Take your needle nose pliers and slide the clamps away. My hoses were a little stuck on there. Push them further onto the nipple of the intake and then attempt to pull and twist. The first hose can be accessed on the passenger side of the engine just after the throttle body. The second line is tucked back there pretty far. Refer to the Figure 4C below.
As for the connectors, there will be a gray plug on the very back near the firewall. Go ahead and remove the plug from the bracket by pushing down on the little tab in the bracket, then slide it right. While your back there, push out the 3 pop rivets on the thick line of conduit. Those wires are stiff and will get in the way later. I had to cut the one on the far left.
Figure 4a. Passenger Side of Intake
Figure 4b. Pop-Rivet-Thing
Figure 4c. Locations of Pop-Rivets (Arrows), Electrical Connector, and Rear Hose
5) Unbolt the intake/throttle body bracket.
This is located on the left side directly below the intake and throttle body and directly next to THAT HOSE I TOLD YOU NOT TO REMOVE. Its held on by two 12mm bolts. I had to use a box wrench on the first one, but could get a socket on the rear. These were on tight, so if you notice in the original tools list, I didn't list the 15mm wrench. I used that wrench for the double-box wrench pry bar trick to break these loose.
Figure 5. Throttle Body Bracket
6) Remove the 5 bolts and 2 stud-nuts from the intake.
Refer to the re-installation picture below for the location and order of reassembly (arguably disassembly) of each bolt/stud. Numbers 4 and 5 are the nuts. I don't know what the issue Nissan has with the number 6, but that sucker is a little bit difficult to get to.
Figure 6. FSM Intake Assembly Diagram
04 Xterra Can Not Remove Lower Intake Manifold
Source: https://www.xterranation.org/index.php?threads%2Fhow-to-diy-spark-plug-and-intake-plenum-gasket-replacement.8203%2F