Does Engine Oil Expire?

If you have some unused motor oil sitting in your garage, you may be wondering if you can still use it. Does engine oil expire?

Yes, engine oil does expire. In most cases, engine oil lasts between 2 and 5 years.

Engine Oil Has A Shelf Life

Oil shelf life

Like oil filters, motor oil has a shelf life. The longevity of your engine oil depends on several factors:

  • Additives: Motor oil comes with a blend of additives to help the oil last longer. Some companies don’t use all the additives to keep their own costs down. The motor oil blends from these companies don’t last as long as motor oil with all the necessary additives. As a rule of thumb, cheap motor oil lasts 1-2 years, and quality oil lasts 2-5 years (if stored the right way).
  • Storage: Poor storage will cause motor oil to break down fast. For example:
    • Viscosity of the oil breaks down when exposed to extreme temperatures.
      • Condensation caused by humidity can cause the oil to turn bad. The moisture can react with the additives in the motor oil. This results in the formation of insoluble particles. Sludge can also form and create a breeding ground for microbes.
      • Freezing temperatures can result in the formation of sediments in the oil.
    • If the motor oil bottle has been opened, the oil can go bad fast. Exposure to oxygen results in oxidation in the oil.

The Ideal Way To Store Motor Oil

If you want your motor oil to stay fresh as long as possible:

  • Don’t open the bottles until you’re ready to use them
  • Store the bottles at an optimal storage temperature between 40 degrees and 85 degrees
  • Keep the oil in a dark place, such as a cupboard in the garage

Look For The Expiration Date On The Motor Oil Bottles

This is the best way to figure out if your motor oil is still good. Not all brands add expiration dates to their bottles, but some do. If your motor oil is past the expiration date, recycle it. If your motor oil hasn’t passed its expiration date, it should be good to use unless it’s been subject to extreme temperatures during storage.

When In Doubt, Buy New Motor Oil

If you put expired motor oil in your engine, it won’t get the lubrication it needs. The expired motor oil no longer has the viscosity to lubricate and protect the engine. It will also degrade much more quickly than fresh oil. This, of course, means that the oil won’t be getting its job done.  Risking premature engine wear to save a few dollars doesn’t make sense. You’re much better off just buying fresh oil.