Hi all, I've been lurking around these forums for a little while now and have gotten a lot of use of the information that is available here! Thought it was time for myself to contribute a little bit
We bought my wife an 04 GX 470 a little less than a year ago. It had 116k on it when we got it and I was unsure what preventive or reactive maintenance had been done too it. We just recently passed 125k on it (a summer road trip was 4k miles in itself) and I finally got some time to look into the maintenance for myself. Recently, while changing the oil I noticed we had a torn up inner cv boot (with very little grease left in the boot) on the passenger side. Deciding to take that project on myself I also decided to go ahead and do the spark plugs and lower ball joints. Ordered 2 cv axles, 2 lower ball joints, and spark plugs from RockAuto. I couldn't have been happier with the customer service and prices RockAuto offered. Out the door total cost for the parts was 232$ after shipping. Enough background story! On to the DIY!!
This is my first DIY post on any forum so excuse me for anything I mess up on
Any questions I can answer Ill be more than happy too!
The OEM spark plugs for the GX 470 are Denso SK20R11 (Iridium) plugs. This is what I bought from RockAuto for $6.57 a piece. There are 8 total in the engine.
First the tools used for this project were: 1/4 ratchet and its 3" extension, 3/8 ratchet and its 3" and 6" extension, 10mm socket, 12mm socket, 5/8 spark plug socket, and screwdriver with socket adapter for 1/4 sockets and 3/8 sockets.
Before starting disconnect the battery. One, I don't like messing with electric wiring with the battery connected. Second, it gives the computer a chance to readjust for the new plugs.
Now to get started you need to remove the cosmetic engine cover it is held in place by two 10mm nuts.
With the cover off you can see the four spark plug coil packs that run along side the engine. (The picture is off the driver side). The coil packs are held in place with a 10mm hex head screw. Remove this screw and set aside (needless to say don't lose them!). You are now able to remove the coil pack. You can either pull the coil pack out while it is still attached to the spark plug wiring harness or you can unclip the harness from the coil pack. Don't let the coil pack dangle from its wiring should you leave it attached.
Next, with the 6" extension attached to the spark plug socket slide it down onto the spark plug and back the spark plug out. I found it easiest in the close quarters to place the socket and extension in first then attach the ratchet aftewards, then unattach the ratchet from its extension once you are ready to pull the old plug out. Then obviously it is the reverse of this process to install the new plug. I torqued the new spark plug by feel but its suppose to be 21 ft lbs I believe. Complete this process for the remaining three plugs on the driver side.