Old Oil - really, really old oil...

[patrickt]

As most here know, I tend to change my oil every three or four years and instead rely on oil analyses from oil sucked out of the pan through the dipstick every 500 miles or so. I spend more money on lab reports than most of you spend on oil changes. But those lab reports consistently tell me that there is no reason to change the oil and, more importantly, act to red-flag any unusual conditions that might be going on inside my solid flat tappet FE engine before they become really bad news. So, I wondered... could I go five, ten, fifteen years this way? 25? How about 50? If you look on the internet there are a ton of non-scientific articles that claim that "oil deteriorates over time so you need to change it based on age as well as mileage." Most seem to use almost the exact same language, like they copied it off the guy before them. But the oil lab people are quite adamant that they simply don't see time as a factor. So I asked, "do you ever test old oil just to see if it's gone bad?" And the answer was "of course we do." And the question, does oil age differently if it's in my pan as opposed to a can on my shelf? Here is the fascinating, and fun, reading on when they analyzed the ebay oils that are now decades old.

https://www.blackstone-labs.com/wp-c...ils-Part-1.pdf
https://www.blackstone-labs.com/wp-c...ils-Part-2.pdf
https://www.blackstone-labs.com/wp-c...ils-Part-3.pdf


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