Hi everyone: I bought a 99 disco1 Wed drive it from Nashville to bloomington IN and before I get it home the low oil pressure light goes on. So I take it to my mechanic and he drops the pan states that It's been dropped twice in the last three months tells me the screen has been taken out. And states that the low oil pressure light is due to a wore out engine and I need another. My light is out when I idle and comes on at 1700rpm. But one time today I was going down the road at 60 mph and the light went out. then came back on but mostly stays on any ideas I don't want to buy a engine? Could it be the oil sending unit?I am not mechanically inclined, so I am at the mercy of you gearheads help.