Silverado’s turbodiesel straight-six looks like a fantastic all-arounder
Inline six-cylinder engines have been proliferating of late and now, for the first time, Chevrolet will be offering an inline-six turbodiesel in the 2020 Silverado full-size pickup truck. The all-new, all-aluminum (with iron cylinder liners) 3.0-liter Duramax engine is rated at 277 horsepower and an impressive 460 lb-ft of torque, which Chevy says is class-leading. Frankly, the new engine looks like it’ll be an outstanding step forward.
Available on LT, RST, LTZ, and High Country trim lines, the double-overhead-cam, four-valve-per-cylinder diesel delivers 95 percent of available torque at just over idle, at 1250 rpm. It drives the wheels via GM’s 10L80 automatic 10-speed transmission, which features a torque converter with a vibration-absorbing centrifugal pendulum for smoother operation. The induction system has been tuned for lower noise, as well. The powertrain also features engine exhaust braking, also known as “Jake braking,” which de-activates the fuel injectors when coasting or slowing, allowing the diesel’s high compression ratio to help slow the truck.
Among the new engine’s other features are Active Thermal Management and ceramic glow plugs for quicker starts and shorter warm-up times in cold weather, even as low as -22 Fahrenheit, without having to use the electric block heater. A water-to-air intercooler cools down the intake charge, which, combined with a low pressure EGR, speeds torque delivery. A variable geometry turbocharger helps balance performance with efficiency, and an electronically controlled variable intake manifold evens out performance as rpms rise and fall. Maximum boost is 43.5 psi.
A deep-skirt design adds stiffness to the seven-bearing block, further reinforced by a lower crankcase extension bolted to the main bearing caps. Lightweight hypereutectic aluminum pistons with high crowns, forged steel connecting rods, and a forged steel crankshaft make up the rotating assembly. The mechanical fuel pump for the common rail direct injection is crankshaft-driven by a chain. The chain-driven overhead cams in turn run off the fuel pump. The variable flow oil pump is also crankshaft-driven, though with a toothed belt, and it matches oil pressure to engine needs, reducing the engine load from the pump. The lubrication system includes cooling oil jets that spray the underside of the pistons.
GM’s new low pressure exhaust gas recirculation system (EGR) continuously adjusts back pressure for optimum efficiency, which is also boosted by a standard start-stop system.
There’s no official word yet, but we can presume the 3.0-liter Duramax will also be available in the Silverado’s cousin, the GMC Sierra. Pricing is $2495 more than the 5.3-liter gasoline V-8, the same upcharge applied to the bigger 6.2-liter V-8 gas engine, and $3890 over the cost of the base 2.7-liter gasoline-powered turbo inline-four.