Oil shelf life

[EBS]

Another question for O & L: what is the practical shelf life for petroleum and synthetic engine oils and hydraulic fluids? Do they deteriorate in sealed containers? Is stability dependent on the severity of seasonal weather changes? How about after they've been placed in equipment? One man's 50 hours may correspond to a year, another's to a month(service hours, that is).
Ed

 

[W5FL]

I believe oil has been stored in the ground for several million years.

Kubota does not rate most maintenance by time - only by hours.

Some other manufacturers rate their maintenance by time and/or hours.

In reality a lot depends on the methods of storage. Oils do not react with metal and the filter takes out the large impurities. The biggest culprit is heat and moisture and that depends a lot on how you use the equipment and how well you do or do not protect it from weather conditions during storage.

The 50 hour maintenance is only the very first break in oils being changed out. After that my Kubota changes most of the oils at 400 hour intervals (350 hours after the 50 hour change) and the filter at 200 hours. Others use 1/2 of these intervals, so you will have to look at your manual.