My 1995 Sedan Deville with the 4.9 had been leaking oil, and until recently, I haven't had a clue why, until I cleaned the engine, and the other day noticed the dirty oil spots on the engine and on the oil cooler lines that go from the engine to the radiator. I tried tightening them, and re-cleaned the area, drove it for 30 miles and inspected the area again. The fresh oil spots were clearly noticeable. Today, I took the lines off and inspected the o-rings on the lines, and they appeared in good condition, so I put some black gasket maker on them and reinstalled the lines. I don't know how well that will work, but time will tell. It was leaking from the oil filter part it goes into, then the middle where 2 separate lines meet, and where it goes into the radiator. Anyone else had this problem?