One August 16, 1996, at 1000 mountain daylight time, a Van's Aircraft RV-4, Mexican registration XBINF, was substantially damaged during a forced landing near Van Horn, Texas. The private pilot was not injured. The aircraft was owned by a Mexican national and was operated by Custom Aircraft of Marana, Arizona, under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the cross country flight that originated from Deming Municipal Airport near Deming, New Mexico, approximately 90 minutes before the accident. A flight plan was not filed. According to the pilot, "about an hour into the flight I noticed oil running down the inside of the firewall. The oil pressure gauge showed low oil pressure to the engine." The pilot further stated that he reduced power and began a gradual descent towards the nearest airport. Approximately 12 miles from Van Horn, Texas, the pilot stated, the "engine failed completely." The pilot performed a forced landing to an area of brush and sand dunes; the airplane came to rest in the inverted position. Post-crash examination of the engine's oil cooler, by an FAA certified repair station for oil coolers, revealed a crack in the first drawn cup tube (see enclosed report).