I have stored vegetable oil that now smells bad. Don’t want to make oil & vinegar dressing from it. Can oil go bad? Never saw any info on that.
Yes, oil can go bad. Because this is a fat-based product, over time the fats will go rancid causing the color, texture and clarity of the oil to change. Some oils, particularly nut oils, go bad faster than others.
If your oil is off smelling, I would definitely throw it away.
Like most shelf stable foods, store your oil is a cool, dark area. Your pantry is a great spot for it. As long as your vegetable oil is unopened and stored properly, it should be fine for at least two years from the expiration date, probably for a lot longer. Once opened, vegetable oil will last up to 12 months. Again, pay attention to the color, texture and smell of your oil if it is around the expiration date or beyond 12 months.
As well, proper storage can also play a part in it’s longevity. For instance, olive oil and vegetable oils are best stored in the pantry while avocado, hazelnut, sesame and walnut oils are best kept in the refrigerator.
This chart  may be helpful in showing the different cooking oils and how long they last.
I hope this helps!