cfair

I was changing spark plugs on a 72,000 mile '05 Jaguar V8 today for the first time for me. This was Jag in the Ford era, now of course it's owned by (ha!) Tata of India.

The 2005 XJ8 has has a 4.2 liter aluminum head V8 with the coil-packs on plugs set up which became popular well after my '66 Oldsmobiles. The design sets the plugs very deep in the head.

With modern cars there's a whole lot less room around the engine to get tools on parts, so I was ready for a 3 hour battle, per the Jaguar forum gang.

As I got into it, I remembered an old trick I probably learned from you guys that bears repeating:
You can use a length of 3/8"s fuel line to slip over the top of a loose spark plug instead of a magnet to remove it from deep in the head.
That same length of hose is very useful to hand spin new plugs in to avoid cross threading aluminum heads.

Turned out I got all 8 plugs replaced and tightened up a loose throttle body air box connection in a just over an hour or so. I even cleaned up the engine bay a bit!

Thanks to all of you here who've taught me so much
Chris

joe_padavano

Chris, the hose on the end of the plug is an old trick for getting plugs started when you have headers that make access difficult. I actually have an ancient tool that is a molded rubber device with the "hose" end and a "handle" end for doing this.

Olds64

Pics, STAT!

I used that trick on the 2003 5.4l Ford Triton engine that I used to own. The problem with those engines is that they had heads with only a few threads retaining the spark plugs. The early 3 valve engines like mine would blow the spark plugs out of the head damaging the threads.

joe_padavano

Unfortunately I'm out of the country until May 17, so no photos anytime soon.

gs72

The trick with those engines or any engine with deep plug recesses. Make sure all the grit is out of the recess before you install the new plugs. I used to break all the plugs loose by maybe half a turn. Then blow out the plug recesses with compressed air. Then remove the plugs and crank the engine over to blow out any reaming grit. Then reinstall the plugs. The grit will get between the plug seat and the head and will blow out while it is running, this causes the plug to loosen and it will start rocking back and forth which wears out the threads and boom the plug tears out the threads. Next is a helicoil if you are lucky, otherwise its time for a new head.