Thanks for the thoughts guys, I finished the R&R of the plugs yesterday and the X definitely is appreciative! I found it easiest to take one coil/plug out and replace at a time, then move on to the next one, made it easier to keep the coils in the right places :thumbup:

I ran my fingers under the valve cover where I could and saw no evidence of oil, I might be ok after all. My theory is that previously in the cars life it had a CCV problem and someone didn't clean the top of the valve cover well enough!

If this slight whistling starts to affect drivability I will entertain smoke testing the valve cover just too see if its a vaccuum hose or something of the like that is worn and needs replacing, funny thing though is that my idle is really unaffected as well as driveability, or perhaps my ears are more in tune to the "whistling" which might be normal operation of the M54?

Mahalo thanks for your thoughts, I am like you and I don't like to take things apart twice and you're right sometimes my intervals are early but I am also a working man who pays his taxes every year (and I'm still waiting on my federal refund after 10 weeks believe it or not but thats another story) and between work on the house and keeping romance alive with the wife my time is valuable as well!

Nice writeup on the procedure. I had the same problem (oil leak) and the parts are cheap and it is not hard to do. I had photos of this job on Webshots, but they sold the company and deleted the directories and comments (bummer, and a cautionary tale about "cloud" computing).

The 15 bolts holding the cover down have a shaft that screws in and then you tighten the nut until it reaches the shoulder. Once you reach that point, stop tightening. It is set to tighten only that far.

If you over-tighten, you snap off the bolt, which is no big deal, as it unscrews from the head. But I had to wait two more days for Pelican to ship me a new bolt.

Lesson learned.....

P.S. - someone mentioned using "sealant" for this job. The valve cover gasket does not require sealant, and I think if you tried to use some, it might actually make things worse.

To Ricky Bobby: the whistle sound IS a vacuum leak. Just for schi*z & giggles, even if you said it looks OK, check again the big rubber boot at the Y. Check it thoroughly.

Good Advice
 

I kept getting these OBD II codes that read, "oxygen sensor adaptation limit reached, Bank X" and thought I needed a new oxygen sensor.

Turned out to be the intake elbow, a $30 part from the online catalogs, which takes about 5 minutes to install. Just a couple of hose clamps.

The little Y that taps off this has a bellows, and sure enough, there was a leak in it, and air got in.

Apparently this confused the modic, which tries to "adapt" the oxygen sensor input, and when the limit is reached, sets of the CE light.

I did end up replacing the oxygen sensors 40,000 miles later, oddly enough, in response to a "Catalytic Converter Efficiency Below Threshold, Bank X" message.

Just because an OBD II code mentions a part by name, does not mean that part is the culprit!

Many dealer technicians fail to grasp this simple point.

Another source of whistling
 

The cyclone (oil) separator plumbing (and there is a lot of it) can leak and cause a whistle.

Some have likened it to a "chewbacca noise" when the car shuts down.

I replaced all of that (the cyclone separator does get clogged, over time) but removed the intake to do so.

Some folks (with smaller hands than mine, apparently) claim to be able to do it with the intake manifold in place...

Chewy usually only speaks on cold-start. There is no need to remove the intake manifold...It'll no doubt give you PLENTY of room to work, but can definitely be done without. Theres plenty of videos on the tube outlining how to do it with the manifold still in place :)

You have smaller hands than I do!
 

My big meaty shiitehooks could not fit underneath!

I did the replacement as a preventative measure. The valve part was pretty gummed up.

The replacement hoses are all insulated, which is standard on the cold weather package.

I tried, but for the life of me, I could not fit my hands under the manifold....

And of course, I lost a fuel injector clip in the process...

I have a spare one on my last parts order to install on my garage shelf, I'll replace and check condition just to "rule it out". Checked CCV and looks good, no chewbacca noises and no change when unscrewing oil cap with car running (no paste either under cap), I just changed DISA gasket as well.

Is rocker cover gasket = valve cover gasket?
My rcg is leaking oil and the quote is $300 for a pair of gasket plus 4 hrs labour.
They really ask for too much.