Which OEM filter are you running (15208-9E000 or the 15208-6****)? The reason I'm asking is that the 15208-6**** is reportedly a cheaper construction/design. I do not know this from personal experience, just from other trusted members of a Maxima forum. I also ask this because pre-BITOG, I used a Fram filter (OK, several of them), and had a very similar noise to your video's on my '97 Maxima's cold starts. Only difference was that mine only lasted several seconds; not nearly as long as yours.
When I switched to higher quality filters (OEM 15208-9E000, Mobil 1, and Pure One's), the sound has been totally absent, regardless of how long my car has sat. It was explained to me the reason was because of the ADBV design/material of the lower quality filters allowed the oil to drain back in the pan, thus the upper end has to wait for oil to fully pump to the top end (on the VQ30, this can take over 30 seconds for full flow according to a post on this board). In your case, this could possibly be compounded by GC's higher viscosity when compared to other 30 weights (thicker oil would take just a little longer to get flowing through the engine if it had all drained back into the pan). That explanation seemed feasible to me at the time, and since the noise has been gone, I haven't given it much more thought.
If you are using a known quality filter (the OEM 15208-9E000 is a good quality filter), could it be possible that something has happened to your ADBV inside from a manufacturer's defect? It's just a quess, but sounds feasible based on my experience of having had the same sound yours currently does when I used filters with questionable quality/ADBVs. And it could explain why yours started mid-OCI.
Regardless, unless you can actually pinpoint an exact other cause of the noise, I would simply change the filter (just the filter, you'll lose about 1/4 quart). It's simple enough on our cars, and a new filter is about $5.00. If it fixes it (which would be immediate), you know the cause. If it doesn't, you're not really out much, and will know to look elsewhere.
I'll post a link to your video on Maxima.org to see if some of them have any other ideas.
I could be wrong in my reasoning above, but your noise sounds identical to what mine did, other than duration. And mine was "cured" simply by going to different filters (of "higher" quality).
Dave
