General Motors continues to enhance its leading portfolio of trucks for the 2005 model year with fuel economy improvements, new models and useful features.

Fuel economy improvements. GM's 2005 full-size pickup trucks and SUVs extend their leadership with incremental aerodynamic and fuel saving technologies that add up to a fuel economy increase averaging 1 mpg across the full-size truck portfolio.

The improvements include a new cooling system consisting of twin electric cooling fans that draw power from the electrical system only when required. A new, patented regulated voltage control system monitors the battery's charge status and controls the vehicle's generator to minimize parasitic losses.

Aerodynamic enhancements include sealed tow hook openings on vehicles without hooks, sealed fog lamp openings, an extended front air deflector, a recessed roof-mounted CHMSL and improved running board aerodynamics.

These improvements have been adopted across GM's entire light-duty full-size pickup and SUV lineup, the highest volume vehicle platform in North America. In 2005, GM expects to sell 1.3 million light-duty full-size pickups and SUVs with a savings of 28 million gallons of fuel at an average of 15,000 miles driven per year. This adds up to one supertanker carrying 1.4 million barrels of crude oil.

Hybrid highlights. Introduced during the 2004 model year for commercial sale, the 2005 Chevy Silverado and GMC Sierra Hybrid models are now available for retail sale. The hybrid promises up to 10 percent improvement in fuel economy while maintaining the performance and capability expected in a full-size pickup. It also provides something other hybrids do not: It is a mobile generator with outlets that can be used for everything from heavy-duty power equipment to a television. The hybrid system is self-sufficient, providing incremental power and recharging itself during braking.

Heavy-duty changes. Sporting a rugged look for 2005, Chevy Silverado Heavy Duty pickups feature a redesigned hood and grille. Both the Silverado and GMC Sierra Heavy Duty pickups boast a 15 lb.-ft. (20.3 Nm) increase in torque on the Duramax 6.6L diesel engine to a segment-leading 605 lb.-ft. (836 Nm) of torque at 1600 rpm when equipped with the Allison automatic transmission.

More potent power. For 2005, an even more potent 310 horsepower (231 kw) version of GM's Vortec 5300 5.3L V-8 is available on 4WD Chevy Silverado and GMC Sierra 1500 Extended Cabs with a standard cargo box. The first of GM Powertrain's Gen IV engine family, the engine features an aluminum block and cylinder heads for lighter weight and high-lift camshaft and compression ratio for more horsepower. Torque is 330 lb.-ft. (447 Nm) at 4000 rpm.

SUV improvements. The Chevy TrailBlazer EXT, GMC Envoy XUV and Envoy XL feature a new Vortec 5300 V-8 engine, rated at 290 horsepower (216 kw) and 330 lb.-ft. of torque (447 Nm). These 5.3L V-8s are equipped with Displacement on Demand, which enables fuel economy gains of up to 8 percent in certain light-load driving conditions by reducing the number of cylinders engaged in the combustion process.

All of GM's midsize SUV's benefit from interior enhancements, including new colors, chrome accents, revised instrument panel cluster, monotone color scheme and revised badging.

Chevy Colorado Xtreme. The new Chevy Colorado Xtreme pickup truck features a sport-truck appearance package and performance ZQ8 suspension.

Chevy Suburban 2WD Z71. With a rugged look and modified off-road suspension, this new 2WD model is ideal for those who have no need for four-wheel-drive but want the appearance and features of the Z71 package including: monochromatic front and rear fascias, Z71-specific tubular assist steps, underbody skid plates, and integrated, stylized roof rack system.

GMC Envoy Denali/Envoy XL Denali. The new Envoy Denali and Envoy XL Denali feature interior and exterior styling cues that immediately identify them with the Denali family.

GMC Sierra Crew Cab Denali. GMC also adds the Sierra Crew Cab Denali model to its full-size pickup line. This new Denali model is equipped with premium Denali-specific exterior and interior styling features and powertrain.