Flat Oot like a ducks Foot
This may be a stupid question, but has the car been sat some place where it might have flooded & you don't know about it?
My first thought was condensation too, especially if the car has only been run up now & again but not brought up to operating temp for any length of time.
On the other story, a family member came round to mine asking me to look at the car after driving 5-6 miles home with a "red light flashing".
I asked if there was an oil can symbol on it. "Yes" was the answer.
Well your engines knackered then!
Said female had hit a lump of metal & burst the sump, then drove the rest of the way home.
A set of bearings & new head later to get it back on the road.
It turns out, that some insurances do cover stupidity!