I got around to changing all 8 Spark plugs today for new NGK Iridium ones.

I know that changing Cylinder 7 and 8 can be a pain so I thought I would document how I got on to give other people a heads up to the process.

Now I didn't follow any manual I just got stuck in, although I did know I had to remove a load of stuff prior to getting to No 8 Cylinder.

The tools I used were as follows:

Various 1/4" socket extensions, 8mm, 13mm, Spark Plug Socket, Rachet, Magnetic Ext pen, Torch, Tape, Posi Screwdriver, 8mm Driver, Wiper Blade removal Tool, Tape measure.



1. Remove Engine covers on each side, they pop off but are hard extract around the piping and stuff. The centre cover unscrews and pops right off. Remove all of the clips holding the window cowl cover panel on, remove the wiper blades and the cover panels on the left and right.





2. Looking to the rear right there is a small plastic cover that allows access to the Cylinder No#8 through the brake reservoir well. Remove the clips holding this cover in place and pull it out. I had to remove the sound proofing at this time because it was in tatters and was sound proofing nothing, You probably will not have to remove it.



3. Here is the view through the hole looking at Cylinder no#8. I placed some paper there so you can see through.



4. This is the cover that was removed.



5. Now you can see my hand has access through the well to the coil pack and spark plug.



6. Right Bank Now... Once this prep work was completed, I then had access to all of the cylinders pretty much unaided. I removed all of the Coil pack cabling and then removed all of the bolts holding the coil packs in situ. One at a time I started removing the coil packs and the spark plugs.



7. Then it was a case of trial and error to get the right length of socket extension to get to the spark plug. Here we see the longest ext to get to cylinder no#8.



8. Sometimes the spark plug fell out of the spark plug socket and had to be extracted using an extending magnet.



9. Once all of the right bank were changed, re-assembly was simple. Replace and secure all of the coil packs. Attach all the cabling, refit the plastic cover by the brake reservoir well. Refit the Window Cowl cover and attach the wipers. Drivers wiper 56mm from the cowl, passenger 61mm from the cowl.
Thats the right bank done.


10. Left Bank. Remove this item (don't know its name!), remove all cabling and screws holding the coil packs in. Uisng your various length Socket extensions replace all of the spark plugs. Cylinder no#7 is easily removed if the electrical trunking cable is moved to one side and secured. A little bit of jiggery pokery and it comes out no problem.



11. Once all the spark plugs have been changed. Reassemble the left bank, screws, cabling and plastic cover. Replace the main centre cover.

Job done. I used the tape to secure the plug socket to the bottom ext bar (whichever it was at the time) as I had some difficulty pulling off the socket from the plug once it was screwed in securely.

These are the pulled old plugs. Right and left banks.

 

That's great Trosty! I'll be coming up on this on my '05.

One thing to note, you might want to mark where your windshield wiper is located before you remove it. If they're like the others I've taken off, it's easy to remount it off a nothe or two and it will hit the edges - I usually mark a line on the windshield right above where the wiper blade parks with a tire stick or something else that will wash off.

 

I measured it , and made a note of it in the text. Its the same as mentioned in the manual if I remember correctly. Driver 56mm at tip from window cowl and passenger 61mm as noted in JTIS.

But of course your idea works just as well. :-)

 

Outstanding! Thanks, wondered what the secret to the #8 plug was, I also am about to tackle this.

Stu

 

Wrong forum, I know, but the above is pretty good for an STR (and I expect the 4.2 NA S-Type). A bit of what I found MAY help non-STR owners. When I did my STR's plugs it was easier than the above:

I didn't need to remove the wipers & cowl (hooray)

but did need UJs and a few socket extensions etc

and a mirror to see the rear (7 & 8) plugs

oh - and didn't need to remove that disc thing (I think it's the PCV valve) as the cover plate flips up (felt a bit scary) if you lift (well, heave) along its bottom edge

I removed the airbox (10mm bolt) and intake trunking to make access easier

On the left rear is EVAP etc stuff which I unbolted (13mm nuts) and jiggled around more than I wanted so I could thread socket extensions through. At 100K miles & 9 years old I figured I'd be bound to split a hose but I'd checked my fuel trims before starting the job and again after and seem to have been lucky.
do it all with engine warm/hot - the plugs come out much more easily (I put the new ones in after it cooled, so did one bank one day and the other bank another so I'd have a warm engine both times)

I shone a light down each plug well to check no pooled oil, and was lucky to find none

I put each new plug in using a length of plastic tubing (brake bleeding kinda stuff) fitted snugly to the electrical connector of the plug - it's easy to guide the plug in, twist gently to start it threading in, then tug to remove the tubing and move to the socket wrench (extension) - the tubing is quite thin so you can see what you're doing better than with a wrench etc I found

Now... I have a UK model and the brake fluid reservoir is on the right (same as driver sits) - wasn't really in the way any more than other things.

Torques:
COP bolt 5 Nm (8mm) - that's not very tight!
spark plug 27 Nm (18 lb ft) - felt more than I liked
yes you do need a torque wrench I reckon

 

I would guess that that roundy thingamabob on the pass valve cover is an pcv valve/return....that would be normal on most engines...but of course Jaguar are not 'most engines'

 

Is than blow by on the old plugs or is it burn oil? I trying to decide between NGK and Denso plugs. What made you choose NGK?

 

They were the first Iridium ones that fitted that I came across while doing a purchase list. There were some recommendations on here somewhere too.

Nothing more than that to be honest, IMO from an end user point of view all spark plugs are pretty much the same and you get what you pay for!


The oil deposit on some of the spark plugs is a bit of a worry. I don't know what causes it but it seems like burnt oil. Here is a good link about spark plug technology that I picked up while working on my Honda motorbike.

Link Click Here

 

how many miles on the plugs when you changed them? Was the car running OK or were you having missing or poor idle?

RyeJag

 

I have no idea how many miles the plugs had been in for, the car was running ok with no missing or idle variance.

I just changed them for peace of mind to allow myself a baseline to work from for the future.

 

Great write up for when I'm ready. Apparently previous owner, was getting error codes and changed plugs at 40K miles on my 2004 XJR. also cleaned fuel injectors.
RyeJag

 

Only yesterday, I was wondering if it would be easier to take the engine out first!

 

Sorry to be slightly off topic, but where (in the pix) and what is a wiper removal tool?

 

Here is a selection of wiper arm removers.

Amazon.com: wiper arm puller

 

Trosty, your photos show the cowl cover and wipers installed was that just for the photo expediency?

Stu

 

It certainly was, I wondered how long it would be before somebody noticed that.
The photo shoot bit was done a little haphazardly to be honest and I should have planned it better.

Maybe next time I will sit down and plan it better.

 

Still an outstanding presentation, won't get around to mine until spring now, 2ft of snow, minus 15 C, and the Jag is in hibernation. Driving a 4x4 now.

Stu

 

thank you so much for this tutorial . definitely helped me a lot to get this job done . I found oil in the wells of #7and8,what should do about it?
Car runs like a dream but I'm afraid that if i neglect this condition it will start going downhill . any help is greatly appreciated !!!

 

I found a way to avoid all the taking apart to get to #8 by using a universal socket knuckle. I posted some pictures which you can find in this thread:
https://www.jaguarforums.com/forum/x...89/#post984896

 

Needs to be added to the FAQ / HOW TO

Nice one, thanks for sharing