Been having a misfire on cylinder 8 so I swapped the coils and misfire didn't follow. Replaced the plug and here's what I saw when I pulled the old one out:

http://zimnox.com/jaguar/plug.jpg

My wrench socket also had a fair bit of oil on it too after it was down in there. The oil doesn't appear to have leaked beyond the threads of the plug, so would I be correct in thinking to replace the valve cover gasket? Is it a difficult job? It was done once before when the car was still under warranty. I have a 140k on the '03 STR.

 

First - I would consider getting NGK plugs into your STR.

Regarding the valve cover gasket change - (I'm referring to my 00 4.0 engine) - The passenger side is easy to replace. The driver's side is a little more challenging as you have to relieve the fuel pressure and release the fuel line to remove the valve cover. (I'm sure the 4.2 SC engine may be different) Not only does the gasket need to be changed but the 4 spark well O-Ring gaskets need to be changed also.

I will tell you what I have done in this situation. I have cleaned out the spark well and applied RTV Black sealant along the edge of the spark well where the spark well O-Ring meets the head from within the spark well (smear w/ your finger) - let dry for an hour then re install the plug & COP.

I did this with success with a minor spark well oil leak to avoid having to change out a new gasket set for one slightly leaking spark well O-Ring (as everything else is holding 100%), although yours looks a little more serious. If you have the resources/time - I would change out those gaskets.

Just my $0.02

 

Bought NGK this afternoon actually. I haven't checked the plugs on the other side yet, just the one that was throwing the code.

 

Kind of surprised that this happened twice on a STR?

We just don't get to many reports of it. I wonder if the first gasket replacement was done correctly?
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I replaced the plug on the cylinder that was misfiring and that fixed that for now.

Only code I'm getting now is P0128, which according to the Ford info on the scanner is a faulty exhaust manifold pressure sensor or vacuum hose disconnected/damaged. Whether or not that is the same description for the code on Jag I don't know, but it would fit with my thought of a manifold leak. There's an exhaust leak somewhere (you can smell it in the cabin when you first start the car) and I had a shop look at it. He said everything looked fine underneath but couldn't really see the manifold from there and that's where we heard the exhaust noise, indicating a possible gasket issue.

Looked up my old paperwork. They replaced both cam cover gaskets and spark plug seals back in march '09 at 81k miles and I'm 140k now. It cost $1k, fortunately it was still under warranty.

Anyone happen to know what the torq spec is when putting the cover back on?

 

Did you get all gaskets/o rings changed out - both sides? Also, possibly a vacuum hose may be disconnected causing your code.

 

According to JTIS P0128 is a thermostat range problem.

 

Norri is right, I just looked up the code in jtis. The thermostat was replaced at around 70k miles ago.

And to answer my own question earlier, the valve cover's retaining bolts are tightened to 7 ft-lbs. In an unrelated note, spark plugs are tightened to 18 or 20, depending on what part of jtis you look at

 

Let us know how you fixed it. Have not seen an STR with that code before. Have you erased it and see if it comes back?
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The jag codes PDF is your friend, rather than a scanner, as it says the known causes as well as the straight meaning of the code.

 

The scan tool I used from Oreily was different than what I've seen before and I didn't find an option to erase the code. Generally, any time I fix something on it, the codes will clear themselves out after a hundred miles or so.

I've noticed another possible issue. There's wet oil(not just dried gunk from spillage) around the supercharger housing. Hopefully my pictures are good enough that someone can get an idea:
http://zimnox.com/jaguar/oilleak1.jpg
http://zimnox.com/jaguar/oilleak2.jpg

Any advice on that would be helpful.

 

They self-clear after 40 cycles with no error but put the MIL out after 3 with no error.

 

The oil does not look too bad and unless you are having problems I would leave it alone. Have you ever changed the SC oil? If not I would for sure replace it now. We have several good sets of inscructions with many good tips on the forum. Try a few searches.

However if you do change it are you aware of the under super charger hose that can leak? This is a $20 hose but many hours and gaskets to get to. So be sure and replace it if you do decide to fix the oil leak.
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I had to order the gasket and o-rings, should have them next week.
I just read the post the other day about changing the SC oil. Do you have to remove the SC to get to the hose you're referring to?

 

Yes. That is the big problem. Plus with the age of the cars we are now seeing EGR tube and EGR valve failures too. So that would be a smart thing to plan on replacing if you go in there.

We have several good threads with pictures showing the hose and the repair.
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