if YOU changed the oil, which is probably not required with so few hours, what type DID you use? It's doubtful that it would create an 'over heating' issue, regardless, but would be nice to know.
We've had ours shut off from time to time, sometimes with no real rhyme or reason, and get the 'normal' code 3-6, which doesn't really tell an owner much. I usually crank the generator right back up, and it runs perfectly fine for the rest of the time I need it, or every time the AGS cranks it thereafter.
two Campers, two Electric cars