Without a VOA you can only guess but, typically we/I think it is additive separation. The recommendation is to always shake vigorously any oil container before dispensing. Ed
Eddie...Thanks for the reply, along with all the others. After reading everyone's input & going back & reading the Pennzoil info, I agree that it "additive separation". I'll try to answer some of the questions asked.
1. One bottle was "new" & one was a half full that had been on my shelf in the garage for several months. The new one was "clean" inside & the one that had been sitting was the one with the 'stuff' in bottom.
2. I buy all my oil(s) at Walmart because it's the cheapest place for the product I use. I always check to make sure it has not been opened when I buy in store, as I've heard of the stories of some people bring old used oil back for refunds. (bad)
3. There was not any "USED" oil either jug.
4. All oil going into the engine looked & was "virgin" oil.
5. "If it is additive fallout, why is it brown?" If you check a freshly opened jug of Pennzoil, the oil looks kind of Honey colored. Here's where I should of read the jug closer.
The print on the label says that the oil is crystal clear when produced & they add "additives" to achieve the "HIGH performance" of the ULTRA.
6. "It was a sign that you were supposed to use an LL-01 or LL-01FE rated oil"

Guess I should have left out the car info.....