The Chevrolet Silverado 3500 HD III (K2XX) Crew Cab Standard Box, equipped with the 6.0-liter V8 engine producing 301 horsepower and paired with an automatic transmission, and capable of running on Compressed Natural Gas (CNG), was a heavy-duty pickup truck produced by Chevrolet for the 2015 and 2016 model years. This variant occupied a significant position within the K2XX Silverado 3500 HD lineup, offering a balance between capability, comfort, and alternative fuel operation. It catered to buyers needing substantial towing and payload capacity, while also seeking the benefits of CNG as a fuel source.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 3500 HD |
| Generation | Silverado 3500 HD III (K2XX) Crew Cab Standard Box |
| Type (Engine) | 6.0 V8 (301 Hp) Automatic CNG |
| Start of production | 2015 |
| End of production | 2016 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol / CNG |
| Power | 301 Hp @ 5000 rpm |
| Power per litre | 50.4 Hp/l |
| Torque | 452 Nm @ 4200 rpm / 333.38 lb.-ft. @ 4200 rpm |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Vortec LC8 |
| Engine displacement | 5967 cm3 / 364.13 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 101.6 mm / 4 in. |
| Piston Stroke | 92 mm / 3.62 in. |
| Compression ratio | 9.6:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV, VVT |
| Engine oil capacity | 5.7 l / 6.02 US qt | 5.02 UK qt |
| Coolant | 15.5 l / 16.38 US qt | 13.64 UK qt |
| Fuel tank capacity | 136 l / 35.93 US gal | 29.92 UK gal |
| CNG cylinder capacity | 67 kg |
| Permitted trailer load with brakes (12%) | 4082 kg / 8999.27 lbs. |
| Length | 6083 mm / 239.49 in. |
| Width including mirrors | 2045 mm / 80.51 in. |
| Height | 1990 mm / 78.35 in. |
| Wheelbase | 3904 mm / 153.7 in. |
| Front track | 1748 mm / 68.82 in. |
| Rear (Back) track | 1709 mm / 67.28 in. |
| Ride height (ground clearance) | 218 mm / 8.58 in. |
| Minimum turning circle (turning diameter) | 15.8 m / 51.84 ft. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission Hydra-Matic |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 355×40 mm |
| Rear brakes | Ventilated discs, 373×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 235/80 R17; 265/70 R18 |
| Wheel rims size | 7.5J x 17; 8J x 18 |
Powertrain & Engine Architecture
At the heart of this Silverado 3500 HD variant lies the Vortec LC8 engine, a 6.0-liter (364 cubic inches) V8. This engine is a member of Chevrolet’s Vortec family, known for its robust construction and reliable performance. The LC8 features a cast iron block and aluminum cylinder heads, utilizing a 9.6:1 compression ratio and multi-port fuel injection. The overhead valve (OHV) valvetrain, coupled with variable valve timing (VVT), contributes to a broad torque curve. The engine’s ability to run on CNG is achieved through a dedicated CNG fuel system installed alongside the standard gasoline system, allowing the driver to switch between fuels. The Hydra-Matic 6L90 six-speed automatic transmission was the sole transmission option for this configuration. This transmission is known for its durability and smooth shifting characteristics, providing adequate gear ratios for both towing and everyday driving.
Driving Characteristics
The 301 horsepower and 333 lb-ft of torque delivered by the 6.0L V8, when channeled through the six-speed automatic, provided a capable, though not exceptionally quick, driving experience. Compared to the available 6.6L Duramax diesel engine, this gasoline-powered variant offered significantly less torque, making it less ideal for extremely heavy towing. However, it provided a more responsive feel than the diesel at lower RPMs. The automatic transmission’s gear ratios were optimized for hauling, with a relatively low first gear for quick acceleration from a standstill when loaded. The CNG capability offered a potential cost savings on fuel, depending on local CNG prices, but also reduced overall range due to the lower energy density of CNG compared to gasoline.
Equipment & Trim Levels
The Silverado 3500 HD III Crew Cab Standard Box 6.0L CNG typically came standard with features expected of a heavy-duty pickup, including air conditioning, power windows and locks, and a basic audio system. The Crew Cab configuration offered spacious seating for five passengers. Higher trim levels, such as LT and LTZ, added features like leather upholstery, heated seats, a premium audio system, and advanced safety technologies. Optional extras included a navigation system, a rear vision camera, and various towing packages. The CNG system itself was often an optional upgrade, adding to the vehicle’s overall cost.
Chassis & Braking
The K2XX platform Silverado 3500 HD featured a fully boxed frame designed for strength and rigidity. The front suspension utilized an independent torsion bar setup with double wishbones, providing a comfortable ride even when unladen. The rear suspension employed a traditional leaf spring design, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, with ABS (Anti-lock Braking System) as standard equipment. The rear brakes were slightly smaller in diameter than the front brakes. The steering system was a cone worm with recirculation balls, providing a stable and predictable steering feel.
Market Reception & Comparison
The Silverado 3500 HD 6.0L CNG variant received mixed reviews. Critics acknowledged its capability and the potential benefits of CNG, but noted that the gasoline engine lacked the sheer towing power of the Duramax diesel. Fuel economy was comparable to other gasoline-powered heavy-duty trucks, but the CNG option offered a potential cost advantage in areas with affordable CNG infrastructure. Compared to the diesel models, the 6.0L CNG variant was generally more affordable to purchase, but had higher long-term operating costs when factoring in fuel consumption for heavy-duty use. The 6.0L engine was also considered more straightforward to maintain than the complex diesel system.
Legacy
The Chevrolet Silverado 3500 HD III (K2XX) 6.0L CNG variant represents a unique offering in the heavy-duty truck market. While not as popular as the diesel-powered models, it provided a viable alternative for buyers seeking a capable truck with the added benefit of alternative fuel operation. Today, these trucks can be found on the used market, often appealing to those looking for a robust and relatively affordable work truck. The Vortec LC8 engine is known for its durability, and with proper maintenance, these trucks can provide many years of reliable service. The CNG system, however, may require periodic maintenance and inspection to ensure safe and efficient operation.
