Does motor oil oxidize or "age" much once opened?
 

I have about 350mL of Elf DID from last fall and another 350mL from this March. Both of them in their original containers, stored with the lid on in my storage unit. I haven't disposed of them because I'm too lazy to do it properly, so the oil just sits there. If I have another 350mL left over after my next change, can I combine them and use them, or should I just take them to an AutoZone and get rid of it?

Does it taste funny?

Speaking as a chemist...
 

if the cap has been on then the oil will be fine. Saturated hydrocarbons do not readily oxidize at room temperature and without catalyst...Considering motor oil floats around at high pressure in your engine at many 100's of degrees fahrenheit for the best part of 5000 miles (~6 months) it's pretty tough.

Cheers,

Nick

Good to know (and logical explanation). Thanks.

ELF is now TOTAL.
 

<ul><li><a href="http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&amp;Number=1154602&amp ;gonew=1#UNREAD">http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&amp;Number=1154602&amp ;gonew=1#UNREAD</a</li></ul>

Yeah, Mike from PureMS pointed that out to me, but thanks for the reminder.

I'm using Elf Excellium 0w-30 in my Accord.