The first time I thought it may be a leaky oil pan gasket so I replaced it (without much analysis because it was easy and the part was cheap). (mechanics.stackexchange.com)
it had new shocks, front end completely redone, new rear halfshafts, newer brakes, has all new injectors, new glow plugs, newer battery, has new filters oil pan gaskets and many more! (shoppok.com)