18 Sep
Today was spark plug day. I was a bit anxious about this, but it turned out fine and had some wild results

#1 plug needed very little coaxing to start and once underway came out smoothly with little effort. As you can see the threads are covered with oil with a dry tip.
#2 plug was the surprise. It needed absolutely NO effort to start and I wouldn't hesitate to say that it seemed like it was only hand tight. Again covered with oil, with a dry tip
#3 was like #1, a little coaxing to start and very smooth removal. Again, dry tip.

So this engine has been an absolute jewel until 2 weeks ago, when the oil leak issue surfaced. Always started by just bumping the button, never any codes, never any driving issues. Always used Premium fuel and very infrequently did it get driven hard.
So why was plug #2 soooo loose. Number 2 is also the one with the tube seal issue or was I looking at small amount of oil that may have been pushed up thru the plug threads and just sitting on the bottom of the tube.

All the new plugs are the same heat range, .043 gap, a smear of anti-sieze and hand tightened til stop, then 1/2 turn

Here are the old ones
Critique?

0.080" is a mess, those things are long gone. The color is dark, but that's probably from weak spark because of the large gap.

Oh, this wasn't the eye opener however. The first surprise was how easy the plugs came out.... These plugs are from the passenger side and the #3 plug well had a bit of oil in it making me think the seal had gone south. The #3 plug was actually loose. It did not require any effort to break free, but I was a bit oblivious to this and went on, thinking the oil in the base was from the seal.

So now I spent a bit of time researching new valve covers that had a replaceable seal vs purchasing OEM (read $$$) and have been trying to find out about these MITZONE aluminum covers, etc. There was a Nico thread as recent as Dec 2022 regarding the install of a set of these, but I haven't received any responses yet as to their suitability once installed. There was an issue with the construction, in that the oil vapor/pcv baffling system (plate) was contained by only using self-tapping screws that merely drilled into the plastic underbelly, rather than a machine screw into a dedicated threaded insert.

This aside, I have to keep moving on and so ordered a set, but they are returnable if a negative response is received. They won't be here until the 25th, so I've let that fly and have moved onto the Right Valve cover.
I didn't want to get too far ahead of myself and thought to finish the passenger side first. After cleaning up the engine on that side, found that the valve position sensors (outside) were completely dry and exhibit no need for involvement in this.
I decided to best use my time to remove the wiring and coil packs from the right bank and followed through with labelling and documenting all the parts and placements. Here is where we get a bit of a surprise.

You recall I mentioned that this engine has never reported a code, never failed in any way, never wavered in performance, response, etc and to me, merely needs a refreshing..

When the coil packs and wiring were removed from the drivers side area, the #2 coil pack was wet with oil.... seriously dripping. The #4 and #6 were fine. Thinking the tube seal was really gone here, I carefully cleaned and removed all the oil and crud from #2 plug well. It was a task to get it all out, but using odd tools, Long stick cotton swaps, mineral spirits and an air pressure tool, it was finally clean enough to remove the plug ..... and when the socket captured the plug, It was already loose by 2-3 turns. I turned it back in and almost reseated it, but had to assure all the crap was out of the well.

Tomorrow I'l be pulling the plug and reporting further.. If anyone has anything to comment on this revelation, please do.. I have wrenched on older cars for almost 60 years and have never come upon a situation where a spark plug was this loose and still ran fine.

Of course these plug threads are longer, but if it would have let loose, it would be tantamount to a 50 caliber going through the hood.....

I can see now where oil vapor being squeezed out of a cylinder through the spark plug threads in #3 and #2 may have triggered an overpressure condition in the pcv system and caused the valve cover gaskets to give up, initiating my problem. Any other rationale would be welcome, but how could a plug get that loose from the factory.



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Definitely sounds like the factory under-torqued the plugs, unless perhaps it had some long-ago warranty work done that you're unaware of. In any case, loose plugs rarely throw codes, and because carbon tends to gradually obstruct the base of the threads, they're often completely asymptomatic like yours.

It doesn't take any overpressure to account for bad gaskets on a 17 year old ride, most forms of rubber get hard and nasty spending 17 years in a dark closet. That's why the first step on every barn-find resto is to replace everything rubber. You know from the start that all of it will be brittle, rotten, or both.

Thanks, good perspective. I'll move on.