In small bowl, mix vegetable oil and ranch dressing mix. Rub all over outside of chicken. Open beer can; with can opener, make several other openings in top. Measure out 2/3 cup beer; discard or reserve for another use. Place half-full can of beer in ungreased shallow 8x8- or 13x9-inch aluminum grill pan. Carefully place chicken cavity over can, pushing until chicken balances in pan.