The Duramax I4 engine is a family of turbocharged diesel I4 engines sold by General Motors in 2.5 and 2.8 liter sizes as an option for the Chevrolet Colorado, GMC Canyon, Chevrolet Express, and GMC Savana in southeast Asia and Oceania (Australia / New Zealand) from 2012, and in North America from 2016 through 2022. They are closely related to the VM Motori R 425 and A 428, and were produced at the General Motors Thailand plant in Rayong.

GM purchased a 50% stake in VM Motori from Penske Automotive in 2007. In 2010, VM released the A 428 (four-cylinder, 2.8 L displacement), developed from the earlier R 428, which was sold in North America briefly as an optional engine for the Jeep Liberty for the 2005 and 2006 model years. Fiat acquired the other half of VM from Penske in 2011 and purchased GM's share in 2013; as part of the sale, GM retained the rights to build engines that had been developed during its ownership, including the A 428.^[2]

In 2011, GM completed a new engine plant in Rayong, Thailand, commencing production in September of the R 425 and A 428 as Duramax XLD25 and XLD28, respectively, for the Chevrolet Colorado and Trailblazer sold in southeast Asia and, under the Holden marque, in Oceania.^[3][4] In 2013, these engines were updated as the Duramax LKH (2.5L) and LWH (2.8L), improving output and fuel consumption.^[5][6]

The Rayong plant began producing the 2.8L Duramax I4 LWN starting in 2015, modified to meet emissions regulations in the United States.^[2][7]