Good questions!
I have noticed that stuff too.
Don't have any answers though.

 

Never noticed that in Amsoil, that being said I just looked at a bottle on the shelf to make sure I wasn't fibbing. Next time I change oil I will look closer when I poor it out of the bottle, but don't see it in the new oil on the shelf.

 

Definitely not normal. Typically if you see this, it indicates "old" oil that has been sitting for a long time and yes it is the addtive package that is separating out. Shaking will NOT reintroduce the package back in, just suspend it. If you see it, don't use it.
Again, this would typically be in old oil, not something you just bought off the shelf....we hope

 

I noticed this too with the SuperTech 5w30 'synthetic' I put in my car. You shake it and the 'sediment' disappears. Let it sit for 1/2 a day and it settles out again. So I don't think it doesn't indicate old oil.

I noticed this for the last 4 or 6 months. The newest bottles I bought from Wally World (3 weeks ago) no longer has this.

 

I tried a little search and found a discussion here back in late 2003 . . .
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=52813&page=1

Some highlights are:

First reply is in from Shell:
"Thank you for your e-mail inquiry. The substance that appears at the bottom of the oil bottle is cause by trace amounts of moisture in the oil. Because of different temperature and humidity changes, moisture can develop in the oil and mixes with some of the detergent additive. The detergents in the oil emulsify this moisture and, if the bottle sits for a period of time, cause it to settle to the bottom. This is not unusual and will not affect the quality or performance of the oil. As soon as the engine reaches operating temperature, the moisture will evaporate through the crankcase ventilation system."

This is the reply from Chevron:
"No need to shake bottle. Occasionally a small amount of calcium carbonate will precipitate from fresh oil on standing. This will not impact the oil's performance in any way. The precipitate need not be transferred with the oil, but doing so will cause no harm."


That thread also discussed to-shake-or-not-to-shake and it was about even. One thought is to leave it lay in the bottle. The other is to shake it in and let the oil filter take out the particles (possibly leaving some of the additives?). So, I'm thinking I'll shake them half of the time

 

Ah! Very good to know this. I, along with many others, have been wondering what that substance is!

 

Ya, thanks jake111.