4.5L Duramax Diesel

Potential Chevrolet/GMC 1500 Diesel Option

News of a 4.5L Duramax option for the 1/2 ton GMC and Chevrolet 1500 pickup models hit mainstream media beginning in 2008, but rumors of the engine surfaced far before. The engine was originally scheduled for release for 2010 model year trucks, but hit hard by the recession a battered GM was forced to re-channel their efforts after the company's deep economic woes compounded. The project was therefore ditched and all prototype engines were reportedly scrapped. After bankruptcy proceedings a new, economically stable GM is rumored to have interest in revisiting the project. Plans to bring the mini Duramax V-8 back into the equation have yet to be solidified.

Note - some aspects of this article are either outdated or irrelevant. For information on GM's Silverado/GMC 1500 diesel option, see: 3.0L Duramax Diesel for Silverado/Sierra 1500 Models

4.5L Duramax Specs


Duramax 4500 LMK, 4.5L Duramax


72 degree V-8 Diesel


4.5 liters, 275 cubic inches

Block/Head Material:

Compacted graphite iron block (CGI), aluminum cylinder heads

Compression Ratio:

16.0 : 1

Injection System:

29,000 psi high pressure common rail, Piezo injectors


Single variable geometry turbocharger


Dual overhead camshafts, 32 valve, 4 valves per cylinder

Emissions System:

Exhaust gas recirculation (EGR), catalytic converter (diesel oxidation catalyst), diesel particulate filter (DPF), and diesel exhaust fluid (DEF or urea injection)


Approx. 310 hp


Approx. 520 lb-ft.

Intended Applications:

1/2 ton Chevrolet/GMC trucks & fullsize SUVs

The 4.5L Duramax was designed with such innovative features as an exhaust manifold exiting directly into the engine valley, a design that Ford's 6.7L Power Stroke utilizes to improve thermal efficiency of the turbocharging process. The 72 degree V configuration results in a relatively narrow engine, reducing dimensional restrictions and possibly allowing an engine to fit into a variety of applications. During the prototyping phase, GM claimed the 4.5L Duramax met Tier 2 Bin 5 emissions standards while providing significant fuel economy improvements over the company's gasoline engine offerings of the time.

GM has since found success in the midsize market with its 2.8L Duramax powered Canyon and Colorado pickups, as Ram Trucks has experienced with its 3.0L EcoDiesel in the 1/2 ton category. If the engine were to resurface, it would compete closely with Nissan's Titan XD, which is powered by a 310 horsepower 5.0L Cummins.