2006 GMC Envoy II XL (GMT370) 4.2i 24V (291 Hp) Automatic

Technical Specifications

Brand GMC
Model Envoy
Generation Envoy II XL (GMT370)
Type (Engine) 4.2i 24V (291 Hp) Automatic
Start of production 2006
End of production 2006
Powertrain Architecture Internal Combustion engine
Body type SUV
Seats 7
Doors 5
Fuel Type Petrol (Gasoline)
Weight-to-power ratio 7.5 kg/Hp, 134.1 Hp/tonne
Weight-to-torque ratio 5.8 kg/Nm, 173.7 Nm/tonne
Power 291 Hp @ 6000 rpm
Power per litre 70 Hp/l
Torque 377 Nm @ 4800 rpm, 278.06 lb.-ft. @ 4800 rpm
Maximum engine speed 6300 rpm
Engine layout Front, Longitudinal
Engine Model/Code LL8
Engine displacement 4160 cm3, 253.86 cu. in.
Number of cylinders 6
Engine configuration Inline
Cylinder Bore 93 mm, 3.66 in.
Piston Stroke 102 mm, 4.02 in.
Compression ratio 10.3:1
Number of valves per cylinder 4
Fuel injection system Multi-port manifold injection
Engine aspiration Naturally aspirated engine
Valvetrain DOHC
Engine oil capacity 6.6 l, 6.97 US qt | 5.81 UK qt
Coolant 13.1 l, 13.84 US qt | 11.53 UK qt
Kerb Weight 2170 kg, 4784.03 lbs
Max. weight 2812 kg, 6199.4 lbs
Max load 642 kg, 1415.37 lbs
Trunk (boot) space – minimum 594 l, 20.98 cu. ft.
Trunk (boot) space – maximum 3041 l, 107.39 cu. ft.
Fuel tank capacity 96.1 l, 25.39 US gal | 21.14 UK gal
Permitted trailer load with brakes (12%) 2722 kg, 6000.98 lbs
Length 5271 mm, 207.52 in
Width 1897 mm, 74.69 in
Height 1917 mm, 75.47 in
Wheelbase 3275 mm, 128.94 in
Front track 1603 mm, 63.11 in
Rear (Back) track 1576 mm, 62.05 in
Ride height (ground clearance) 203 mm, 7.99 in
Minimum turning circle (turning diameter) 12.6 m, 41.34 ft
Approach angle 34.5°
Departure angle 23.5°
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 4 gears, automatic transmission Hydra-Matic
Front suspension Double wishbone
Rear suspension Independent multi-link suspension
Front brakes Ventilated discs
Rear brakes Disc
Assisting systems ABS (Anti-lock braking system)
Steering type Steering rack and pinion
Power steering Hydraulic Steering
Tires size 245/65 R17
Wheel rims size 7.0J x 17

The GMC Envoy II XL, specifically the 4.2i 24V (291 Hp) Automatic variant, was a single-year offering in 2006, representing a significant refresh of GMC’s mid-size SUV. Built on the GMT370 platform – shared with the Chevrolet TrailBlazer and Buick Rainier – this iteration aimed to deliver a more powerful and refined experience than its predecessors. The 4.2i Automatic trim occupied a mid-to-upper position in the Envoy II XL lineup, balancing performance with a comfortable feature set, targeting families needing towing capacity and space. It was a transitional model, bridging the gap between older body-on-frame designs and the more modern crossover SUVs that were gaining popularity.

Powertrain & Engine Architecture

The core of the Envoy II XL 4.2i was the LL8 engine, a 4.2-liter (253.86 cubic inches) inline-six cylinder engine. This engine replaced the previously offered 4.3-liter V6, offering a more modern design and increased output. The LL8 featured a cast iron engine block paired with aluminum cylinder heads, dual overhead camshafts (DOHC), and four valves per cylinder. This configuration allowed for improved breathing and higher engine speeds. Fuel delivery was managed by a multi-port fuel injection system, optimizing combustion for both power and efficiency. The engine produced 291 horsepower at 6000 rpm and 377 Nm (278.06 lb-ft) of torque at 4800 rpm. The engine was mounted longitudinally and drove the rear wheels, a common configuration for body-on-frame SUVs of the time. The LL8 was mated to a four-speed Hydra-Matic automatic transmission, selected for its proven durability and suitability for towing applications. While reliable, this transmission lacked the gear ratios found in newer automatic transmissions, impacting fuel economy and overall refinement.

Driving Characteristics

The 4.2i Automatic Envoy II XL offered a noticeable improvement in acceleration and responsiveness compared to earlier Envoy models equipped with the 4.3L V6. The 291 hp engine provided sufficient power for highway merging and passing, though it wasn’t designed for sporty performance. The four-speed automatic transmission, while smooth, had relatively wide gear ratios. This meant the engine could feel somewhat strained at higher speeds, and fuel economy suffered. The rear-wheel-drive setup provided a traditional SUV driving feel, offering good stability but lacking the all-weather capability of four-wheel-drive versions. The automatic transmission prioritized smooth shifts over aggressive downshifting, making it well-suited for comfortable cruising and towing. The overall driving experience was geared towards practicality and comfort rather than outright performance.

Equipment & Trim Levels

The Envoy II XL 4.2i Automatic came standard with features like air conditioning, power windows and locks, a CD player, and cloth upholstery. Higher trim levels, often bundled as option packages, added features such as leather seats, a premium sound system, heated front seats, and a sunroof. The interior design was functional and spacious, comfortably seating up to seven passengers, although the third-row seats were best suited for children. Optional extras included a navigation system, a rear-seat entertainment system, and upgraded alloy wheels. The interior materials were generally durable and aimed at providing a comfortable and practical environment for families.

Chassis & Braking

The Envoy II XL utilized a traditional body-on-frame construction, providing a robust and durable platform. The front suspension employed a double wishbone design, while the rear featured an independent multi-link suspension. This setup aimed to strike a balance between ride comfort and handling stability. Braking was handled by ventilated discs at the front and solid discs at the rear. An Anti-lock Braking System (ABS) was standard, enhancing safety during emergency braking. The vehicle’s substantial curb weight of 2170 kg (4784.03 lbs) required a capable braking system, and the Envoy II XL generally provided adequate stopping power for its class.

Market Reception & Comparison

The 2006 GMC Envoy II XL 4.2i Automatic received generally positive reviews from automotive critics. The new inline-six engine was praised for its power and refinement, representing a significant improvement over the previous V6. However, the four-speed automatic transmission was often criticized as being dated compared to the five- or six-speed transmissions becoming increasingly common in competing SUVs. Fuel economy was also a point of concern, as the Envoy II XL wasn’t particularly efficient. Compared to the mechanically similar Chevrolet TrailBlazer, the Envoy II XL offered a slightly more upscale interior and exterior styling. Against competitors like the Ford Explorer and Toyota 4Runner, the Envoy II XL offered a compelling combination of power, space, and towing capacity, but often at a slightly higher price point.

Legacy

The 2006 GMC Envoy II XL 4.2i Automatic, being a one-year-only model, occupies a unique niche within the Envoy family. The LL8 engine proved to be relatively reliable, though regular maintenance is crucial to prevent issues like oil leaks and potential timing chain wear. On the used car market, these Envoys are often sought after by buyers looking for a capable and affordable SUV with a powerful engine. The Hydra-Matic transmission, while durable, can exhibit issues with harsh shifting as it ages. Overall, the Envoy II XL 4.2i Automatic represents a solid and capable SUV that offers a good value proposition for those seeking a robust and spacious vehicle, particularly for towing and family transportation.

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