Oil shelf life

[Matchless?58]

Hi all
I have just rediscovered a 25 litre drum of 10/40 diesel engine oil . It's been sitting in my storeroom for at least 10 years ! I bought it to do an oil change on my Nuffield tractor and forgot all about it . Needless to say the Nuffield has had lots of oil changes which I bought more oil for ! Don't know how I forgot it was there but busy life kids work etc is my only excuse .
Now I want to do an oil change on the JCB .
My question is will this oil be ok to use after standing for over 10 years in a sealed drum in my storeroom or will the oil have broken down in some way ?
I don't want to use it if there is any possibility of damaging the engine . Does oil lose its effectiveness after long periods in storage ?
I don't want to chance it if there is any risk at all .
All advice/opinions welcome .
Cheers Chris

[essexpete]

I think overtime it can degrade and if there is any element of doubt then don't use it.

[Slooby]

Is it a mineral oil, semi-synthetic or synthetic?

Basically any modern oils with a semi or fully synthetic make up do tend to have a shelf life (2 to 5 years depending upon the additives), especially if opened to atmosphere (6 months at best). They really do not keep well.

But a base mineral oil, if still sealed and moisture free, 'should' be ok for a far longer shelf life. Best way to check is open it up and take a look inside; if the oil looks like clean fresh oil with a consistant golden honey like colour with no cloudiness, gelatinous clumps or bits swimming in it and it doesn't smell bad (trust me an ester based semi or fully synth really does smell grim when it's oxidised). At the end of the day though it's down to you; if anything looks or smells 'off' use it in the lawnmower or dispose of it responsibly...not mixed like two stroke oil with heating oil for fuel, no, that would be very naughty...

[Matchless?58]

It is mineral oil but based on the replies I think I will not be using it in any of my engines .
Plenty of other uses for spare oil anyway . Just don't know how I could have forgotten it was there . I did cover the drum with a dust sheet so I guess out of sight out of mind etc .
Thanks for the replies .
Cheers Chris

[mechman]

On a bit of a tangent lincs wold railway are looking for someone who wants about 100 gall of old engine oil for whatever purpose.

[Matchless?58]

Take me about 300 year's to use that lot in my little oil can !

[essexpete]

Think the railway will have to bite the bullet on that one. Does a reasonable quantity of waste oil have a small value?