Pedro Arrais review: Sierra's diesel option a standout


The big news surrounding the 2020 GMC Sierra is the ability to pick a 3.0-litre straight-six Duramax diesel engine among the various powerplant options.

Full-size diesel pickups aren’t big news usually — in fact, they are fairly common. But customers in the past couldn’t get one in a light-duty truck (commonly referred to as a half-ton). They had to move up into the heavy-duty model (referred to as a three-quarter ton).

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What is also significant is that the new engine is a straight (or inline) six-cylinder, compared with the V-6 configuration offered by other manufacturers.

The most likely reason for the choice would be to lower noise and vibration, thanks to the superior balance of having the pistons arranged inline.

The 2020 GMC Sierra 1500 lineup starts at $31,798 for a regular cab with a long bed and two-wheel drive. My tester was a crew cab (four doors) with a short bed (1,776 millimetres). It came equipped with four-wheel drive as well as the 3.0-litre turbodiesel. Six trim levels are available. My tester came with the AT4 package, with enhanced off-road equipment, including a two-inch factory-installed suspension lift and skid plates. It has a list price of $62,298.

If you ever had a diesel before, transitioning to the new engine might take a few minutes. Unlike in the past, you don’t need to wait for the glowplugs to heat up. Startup is instantaneous.

The second thing you notice is the noise — or lack of any. It is now as quiet as a gasoline engine.

Diesel fans aren’t wrapped up in the horsepower of an engine. They want to know how many foot-pounds of torque it delivers. The Duramax doesn’t disappoint, producing 460 lb.-ft. of torque at a low 1,500 rpm (power comes on even lower, at 1,250 rpm). Peak horsepower is 277 at 3,750 rpm.

The General Motors engine is more powerful than the Ford, but less than the Ram, should you compare power between the Big 3.

While it can’t boast best-in-class power, in smoothness it decisively takes the field.

Power delivery is as smooth as a V-8, especially mated to GM’s new 10-speed Hydra-Matic automatic transmission. Punch it and the engine roars — a purposeful roar that is low and deep and ready to get to work. If you listen hard enough, you might even hear a bit of diesel clatter at a certain point, but it disappears quickly.

Along with fewer parts than a V-shaped engine, including balancing shafts, overall weight is kept down by the use of an aluminum block and cylinder head. The block retains iron cylinder liners for durability.

While powerful, GM does trail the competition in towing capacity. With 4x4 and a crew cab, my tester’s maximum trailering capacity was 4,218 kilograms — typically a small trailer, camper or boat. It shares maximum payload numbers — 982 kg — with its 5.3-litre V-8 gasoline-powered brethren.

You will need to go up to the Sierra 2500 HD diesel if you want more. Both Ford and Ram claim higher towing limits.

Another reason many people look for a diesel is for fuel economy, and the GMC diesel doesn’t disappoint, with a 10.5-litre-per-100-kilometres rating in the city and 9.1 on the highway. The engine also incorporates engine stop/start for city driving, although it not as quiet as a gasoline engine when it restarts.

Another area where the Sierra shines is in the interior. The GMC badge ensures it is a cut above a similarly equipped Chevrolet Silverado.

I would not be going out on a limb to suggest the fit and finish on my tester rivalled a number of luxury cars.

Because it is a truck first and foremost, all the knobs, dials and buttons are both large and purposeful. This is a full-size truck and the interior reflects that as well, with more than generous dimensions for even large individuals.

The bottom of the back seats fold up to hold bulky items and the backs also open, revealing a small cubbyhole behind.

My tester came with one of the more innovative options in a pickup — a six-position rear tailgate that can be converted into a step, work surface or load stop. The tailgate could also be lowered remotely.

The Technology package includes an eight-inch infotainment screen with surround vision, rear camera mirror (you can select between a regular mirror or a wind-angle camera image), head-up display, bed-view camera and provisions for two trailer view cameras.

The Driver Alert Package comes with low-speed forward automatic braking and front pedestrian braking, among other features.

The full-size pick-up truck market is a profitable segment for manufacturers, and this drives innovation among the players. The 2020 GMC Sierra with the 3.0-litre turbodiesel is a prime example of how competition improves the breed.


Type: Full-size four-door pick-up, front engine, 4X4

Engine: Turbocharged 3.0-litre six-cylinder diesel, 277 hp at 3,750 r.p.m., 460 lb.-ft. of torque at 1,500 r.p.m.

Transmission: 10-speed automatic

Dimensions (mm): Length, 5,886; width, 2,063; height, 1,990 ; wheelbase, 3,747

Curb weight (kg): 2,193

Price (base/as tested): $62,298/ $77,448 (includes $1,900 freight and PDI and $100 AC tax)

Options: Diesel engine $3,245, technology package $2,740, AT4 preferred package $1,995, 20-inch machined wheels $1,395, power sunroof $1,325, driver alert package II $1,260, driver alert package I $1,095, trailer tire pressure monitor system $95

Tires: 275/60 R20 all-season tires

Fuel type: Diesel

Fuel economy (L/100km): 10.5 city/ 9.1 highway

Warranty: Three years/60,000 km new vehicle, five years/100,000 km powertrain and roadside assistance

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