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Hi there. Does anyone know the shelf life of engine oil such as Pennzoil Platinum Euro, or synthetic oil in general? I realized earlier this year I have an unopened jug from maybe 3 years ago sitting in my non temperature regulated garage. I’m wondering if it’s best to toss it. Thank you!

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I probably could've done some due diligence and searched before posting; something I'm clearly a hypocrite of in this instance and generally recommend others to do as well.

From Pennzoil themselves:

Motor Oil Bottle Storage – At home, motor oil should be stored in a clean, dry place such as a cabinet or shelf. Make sure to check older motor oil to see if it is still good and on the specification for your vehicle’s engine even if it is the proper viscosity grade. Pennzoil Platinum motor oils can have a shelf-life of up to four years if stored properly. Old motor oil should be properly disposed of if no longer useable.

...

Additionally, please keep in mind that in a home or garage, the recommended storage temperature for motor oil is between 40 and 85 degrees Fahrenheit. It is best to make sure it is not kept in a location where it can get too cold or too hot to maintain the lifespan of the motor oil.

Reference: https://www.pennzoil.com/en_us/educa...l-storage.html

Looks like I'm going to dispose it, since my garage has definitely seen temperatures under 40F (~4C).