As these cars get older the oil seals around the top of the spark plug holes start to weep particularly towards the rear as it hotter.
While tracking down a restricted performance misfire I found the following.
The plug hoes can have 1.5in of oil in them and the plug fire fine as its inside the rubber tube attached to the coil. Once you take out the coil pack the oil floods the plug and when you put the pack back it floods inside the rubber tube and you get a misfire.
Unless when you pull the pack the tube is bone dry you must blast out the plug hole with compressed air before replacing the coil pack. (or taking out the plug)
To compensate for some lack of elasticity in the old rubber tubes I have put an "0" ring around the outside at the plug end to squeeze the rubber a little around the plug ceramic. Origin OD is 19mm so a 22mm x 2.5 nips it fine

 

I was working on a negected 4.0 and had oil pooled around almost every plug. I was lucky enough to have some thin tubing that would slip over the plug and in the chute. The tubing would slip up in my shop vac hose and it didn't even need a fit tight. Notches in the bottom of the tubing let enough air flow by that the plug bore cleaned out really well, then cleaned the plug boot and plug.
Worked for me! I'm always scavenging hose, wire and metal parts to cobble up quick fixes and was lucky to have the right thin wall tubing.

 

I think the worst is No3 Left bank as when topping up the oil if the coil cover below is not full sealed it lets oil through which runs into the plug holes

 

That oil might be a good thing indirectly. Have found that it keeps plugs from seizing in place after a long time in service. i used a little copper anti-seize, some might argue not the best thing to do but was careful. However, since these are not well sealed areas, road water splash and dampness from condensation could work its way into there. Without oil or something else present, the plugs could get oxidized into place.

 

If they're NGK plugs they already have anti-seize and NGK say not to add any.

 

Yes, you are correct. Well, one day in the future i will find out if i messed up something by doing this.

 

Some good ideas! I ran into the same thing. You know, good thing I saved the ignition coil, maybe its ok after a good cleaning.

Ok, want a laugh? How did i remove the oil last time I was in there? I grabbed a hypodermic syringe, suck some in, squirt it out, suck in, squirt out . . .

At 4 or 5ml per "suck" - that takes a while :-)

FYI - Syringes come with needles of different guages. These were used to inject a medicine thats kind of thick viscosity wise, so I had some that worked okay. I wouldn't want to try to suck up oil with standard guage Syringes! (What a forum - learn about Jaguars and Syringes!)

John

 

Amazon has plastic syringes in all sizes from 5ml to 500 ml and beyond. They are very inexpensive.

Using the right size for the job makes short work of the task at hand.

Z

 

it usually taper seat plugs that seize ....and then snap off ...jag did something right.

 

I keep our used veterinary syringes for the various automotive jobs these vehicles require from time to time. If you remove the needle, you can suck up much more fluid with each pull of the plunger....