How long doe synthetic motor oils remain useable ?

[MinamiKotaro]

I have my doubts that the oil goes bad. The shelf life is probably because the bottle starts breaking down and contaminating the oil, especially if it's kept in heat and/or the sun.

 

[demarpaint]

Here's an article about old oil, very old oil. I believe this was posted here before. After reading it I'd say a five to ten year shelf life is a walk in the park for dino or synthetic oil.

http://www.blackstone-labs.com/Newsletters/Gas-Diesel/April-1-2012.php