Here is what my plugs looked like:



I thought I had another better picture but the phone swallowed it.

This is after 63K. Didn't look bad.
Out of the 3 in the back 2 of them had a puddle of oil inside the valve cover tube so I suspected the oil seals were gone. So I ran the engine at 2k cold for a little bit after cleaning out the oil from the tubes and I did not see any oil seep out. So I suspect the PCV valve is sticking close so the oil will break out of the seals with the help of crank case pressure.

I did not take off the upper plenum, I instead took off the intake tract (aluminum duct that throttle body is bolted to that bolts to the back of the upper plenum. I ground down the corner of the intake manifold where the blue and green connector sit on via a bracket. Don't understand why Nissan had to put the one coil crooked so the screw sits sorta underneath the intake manifold corner.

I thought that taking 7 bolts rather than 11 will probably save time. Also, not having to remove a few of the sensors mounted on the intake from what i read a while back. Most of the time i spent grinding the corner carefully not to mess up the coil. Plus I guess I'll save money on gaskets the next time around I do a plug change.
They wanted like $40 for the gasket set. Although yes, there is a gasket that goes betweeen the intake tract and the upper plenum but will probably be a bit cheaper to replace than the plenum gasket. I didn't replace mine as it was in good condition. Anyway, I'll time this next time to see how long it takes me.

 

It would have been faster to just remove the plenum, most of the work in removing it is the bracket that attaches to the elbow anyways.

Anyways for the plug seals, it's the seals and they are built into the cover on 3.5's, order a rear cover from an 04+ maxima, it's cheaper and some suspect it's redesigned without this problem.

 

plugs dont look THAT bad..definitely can see there was oil down there though.. How much does a 04+ VC typically run?

 

Most of the work is removing the bracket? That was actually the quickest thing to come off

thanks for the tip on the 04+ seals.

for right now I'm gonna leave it like that. The oil found there was probably and most likely for a perio of 63K, plugs hadn't been changed before. I plan on changing the plugs again in 6 months or maybe sooner.

 

Nice write up, I am about to do this plug change in the next hour. I was planning to do the samething with just taking the plenium tube off only. The gaskets where only $6.00. That included the tb gasket. We'll see how that bracket goes.

I have 91,000 miles on the org. plugs, and I took the front three out to check them, o that was bad. The white insulation around the top was cracked, and just fell off.

 

Well, I ended up taking the plenium off. I really didn't feel like spending half the day trying to get the coil out from under it.

Question I have now is: can I reuse the plenium gasket?

 

Well yeah, most of the time taken will
be grounding down the plenum corner to be able to get the plug off.

I would not reuse the plenum gasket, my rule of thumb is never reuse any major gaskets, and this is one of 'em. I did reuse the gasket that sits between the tract and plenum but if it leaks its a quick 15 minute job to change, however the gasket was in perfect condition, but like I said, I wouldn't reuse a upper plenum gasket.

 

what do u guys use for plugs i was thinking those new pulstar plugs but idk i might just stick with the ngk iridiums lmk what u guys use