So you shouldn't use oil that has been sitting around unused in the containter ?

I would use it, as long as the vehicle you’re putting it into calls for 0W-20.

 

IF by "half a container" he means half a quart.......it should not matter what "it calls for" and it will be fine for adding to whatever is in there.

 

Took a look over at bitog. There’s one mention, that if oil was stored cold enough to freeze something might separate out. Other’n that no worries. And you’re in California.

I routinely have motor oil in previously opened containers, sitting in garage, 6~12 months. Never gave it a thought.

With brake fluid and Toyota ATF WS you need to be more careful though: if not used immediately I’d recycle those.

 

def use...no issues

 

The stuff is already rather old. An extra few months in a bottle won't hurt anything.

I regularly save the heels from each oil change to get a free one every so often.

 

It's been bouncing around your trunk for a year or so - I'm pretty sure that oil is going to face a much harsher environment when you dump it into your engine block.
Oil manufacturers state one year warranty/change cycle to sell you more oil. Kinda like the expiration date on your bottle of water. I'd pay a little bit more attention to things like that, since I'm consuming it. Before you ask; I do drink expired bottles of water.

 

Check the Valvoline website. They say it's OK subject to some caviots. If the bottle was never opened, it's OK. I don't know about a semi-used container though.

 

I've never had an engine dye on me, by putting in partially used containers of oil to top-off my crankcase. "knock on wood"
Even when they've been sitting in my garage for several years.
I have had friends engines die on them, for lack of oil in the crankcase . She keep driving the car with the oil lamp lit, because she was only 10 miles from home. Bearing and rod knock afterwards; but that 4runner still ran.

 

It's fine. Yeah, it has seen more exposure to air and water than an unopened bottle, but those really don't start doing anything until the oil hits engine temps.

The dates on water bottles is because of NJ law, and its cheaper for company to just label all their bottles with such than risk shipping undated to NJ.