One More Time: GM Interested in Light-Duty Diesel Again

If the reports are to be believed, General Motors has reignited interest in its shelved 4.5-liter Duramax V-8. Originally intended for the light-duty Chevrolet Silverado and GMC Sierra, the baby Duramax could also spread to the heavy-duty truck lineup.

According to's sources, certain powers at GM are keen to revive the in-house-designed Duramax, designated LMK, especially since it is ready for implementation. With stringent fuel economy and emissions standards ever under state and federal microscopes, a well-developed diesel powerplant could provide an edge in fleet averages, with the performance to boot. First planned for the half-ton, or 1500, truck lineup, GM's truck team is also reportedly interested in sticking the 4.5-liter turbo-diesel V-8 into the three-quarter-ton Silverado and Sierra as well. The question is, of course, would it sell?

"[The 4.5-liter Duramax] would have launched [with power ratings] about where the Duramax was in 2001 when it was introduced," Duramax chief engineer Gary Arvan said.

The 2001 Chevrolet Silverado 2500 HD with the 6.6-liter Duramax V-8 puts out 300 horsepower and 520 pound-feet of torque. Compare those figures to the current LML-series Duramax -- 397 horsepower and 765 pound-feet of torque -- and you can see how the diesel engine has advanced in close to 10 years. Hauling and towing performance would be slightly different but the smaller-displacement V-8 would help achieve more miles per gallon, reportedly somewhere in the range of 25-percent better versus a comparable gasoline engine.

"The 4.5-liter V-8 is fully developed and ready," GM full-size truck chief engineer Mark Cieslak said. "[If we decided to offer it] we could launch it in a heartbeat."

Price-wise, there's no doubt the LMK-series Duramax would command a premium over a conventional V-8 engine. However, it would also likely cost less than the top-level 6.6-liter V-8.

What do you think? Should GM sweep the dust off its 4.5-liter Duramax V-8 and put it into production? And should the baby Duramax come in a light-duty truck, heavy-duty truck, or both? Sound off in the comments below.


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