The General’s 4.5-liter Duramax V-8 had been under development for nearly four years and was scheduled to make its public debut for the 2010 model year, up until news broke a couple months ago that the light-duty diesel would be shelved indefinitely in the face of declining fuel prices and GM’s own fiscal dilemmas. With the light-duty Duramax currently on standby, the only option remaining is to wait until the market is ready for high-volume light-duty diesel applications. According to GM vice chairman of product development Tom Stephens, “The program is essentially complete and could be implemented whenever we choose to do that.”
If GM had proceeded with placing the 4.5-liter Duramax into the popular Chevy Silverado and GMC Sierra, it would have been the only automaker in the U.S. to offer a light-duty full-size pickup truck. Chrysler, Ford, and Toyota, who all had plans at one point for a light-duty diesel application for their respective full-size trucks, have put their diesel plans on hold as well. In addition to the Silverado and Sierra, the 4.5-liter Duramax could also be placed into future SUVs and CUVs.
The 4.5-liter Duramax utilizes a design where the flow of air and exhaust gases entering and exiting the cylinder heads is reversed. The turbocharger is placed in between the cylinder banks to save weight and space, and all exhaust gases exit toward the center of the engine. The new design also helps improve performance and reduce emissions.