On November 18, 2001, about 1324 eastern standard time, a Ercoupe 415-C, N99236, registered to an individual, collided with a tree and the ground while making a forced landing following loss of engine power near Southern Pines, North Carolina, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane received substantial damage, and the airline transport-rated pilot and 1 passenger were not injured. The flight originated from Parkton, North Carolina, the same day, about 1245. The pilot stated that prior to takeoff he added 1.2 quarts of oil to fill the engine oil tank and then did a short test flight over his home airport. After the test flight he found no evidence of engine oil leakage from the engine. At 1250, he departed Parkton for Southern Pines. When about 10 miles from the Southern Pines Airport, the engine began to run rough. He continued toward the airport. The engine oil temperature began to climb and the engine oil pressure began to drop. The engine lost power and they could not make it to the airport. While making a forced landing on a golf course, the left wing collided with a tree and the airplane descended and collided with the ground. Postcrash examination of the airplane by an FAA Inspector showed the propeller had damage consistent with very slow rotational speed at ground impact. The engine cowling and bottom side of the engine had oil spray on it. The engine oil tank contained no oil. Examination of the engine by an FAA Inspector at an engine overhaul facility showed the front crankshaft seal was dislodged and allowed oil to escape from the engine at a substantial rate when the engine oil system was pressurized. No obstructions in the engine case vent system were found that would have caused over pressurization of the engine case. The reason for the dislodge crankshaft seal was not determined. (See FAA Inspector Statements.)