Buick Motor Division will introduce a mid-size sport/utility vehicle named Rainier for the 2004-model year, extending its truck portfolio following the launch of Rendezvous, a crossover vehicle.Rainier, a five-passenger, full-frame SUV, will be powered by the Vortec 4200 inline six-cylinder engine. It will feature an optional Vortec 5300 V8 engine that will be available at a later date. The availability of this V-8 engine is exclusive to Rainier on GM's short-wheelbase midsize SUV architecture. Rainier will be introduced in dealers' showrooms in September 2003.The 275-horsepower Vortec inline six-cylinder engine, with the 4.10 axle and four-speed electronically controlled automatic transmission, give Rainier a maximum towing capacity of 6,300 lbs. for two-wheel models and 6,200 lbs. for all-wheel drive models, the highest towing capacity in the segment.The available Vortec 5300 V-8 delivers 285 horsepower at 5200 RPM and 325 lb.-ft. of torque at 4,000 rpm. Both 3.42 and 3.73 axle ratios are available.