Review: Mercedes-Benz W164 M-Class (2005-11)

Review: Mercedes-Benz W164.I M-Class (2005-08)

Overview

Released in September 2005, the Mercedes-Benz W164 Series I (W164.I) M-Class was a large, four-wheel drive SUV. Manufactured in Tuscaloosa, Alabama, the W164 M-Class range initially consisted of the ML 320 CDI, ML 350 and ML 500 Luxury models. From July 2006, however, the ML 320 CDI and ML 350 were solely available as Luxury variants, with the ML 280 CDI serving as an entry-level model. From October 2007, the ML 500 was fitted with a 5.5-litre V8 engine, replacing the 5.0-litre unit used previously.

Please note that the Mercedes W164 ML 63 AMG has been reviewed separately.

4ETS four-wheel drive system

The W164 M-Class had a permanent four-wheel drive system with open differentials. The transfer case was directly flanged to the 7G-Tronic transmission and used propeller shafts to equally distribute power to the front and rear axles (i.e. a 50:50 front:rear torque split); a bevel differential was used to compensate for differences in the rotational speed between the axles.

Mercedes-Benz’s ‘4ETS’ electronic traction system controlled the torque distribution between the wheels. If a wheel lost traction, 4ETS would apply brief braking pulses to transfer torque from that wheel to the wheels with traction.

For the W164 M-Class, the four-wheel drive system gained the following functions:

• Off-road ABS: active at speeds below 30 km/h, Off-Road ABS was designed for poor surfaces or steep downhill gradients. At regular intervals, the front wheels would be automatically braked with sufficient force that they would lock up – this would cause the vehicle to dig into the loose surface and come to a halt more easily. As a result, braking distances could be significantly reduced;
• Downhill Speed Regulation (DSR): designed for steep downhill gradients and activated by pushing a button in the centre console. With DSR, vehicle speed would be kept constant by engine and transmission control, and automatic braking. While the system would initially set a speed of 6 km/h, the driver could use the cruise control stalk to set the desired downhill speed between 4 km/h (minimum) and 18 km/h (maximum); and,
• Start-Off Assist: helped the vehicle more safely accelerate from rest when on steep uphill gradients, by preventing the vehicle from rolling bac kWards as the driver moved their foot from the brake pedal to the accelerator. During this period, brake pressure would be provided by an ‘actively controllable’ brake servo unit. Start-Off Assist was automatically activated by an inclination sensor.

Off-Road Pro engineering package

As an extra-cost option, the W164 M-Class was available with an ‘Off-Road Pro engineering package’ which included:

• A two-speed transfer case with a 2.93:1 low range ratio for off-road use. The low range ratio could be engaged while the vehicle was in motion, providing vehicle speed was below 40 km/h and the gearshift lever was in the neutral ‘N’ position. Maximum speed for shifting from the low range ratio to the standard ratio was 70 km/h;
• A multi-disc differential lock that was integrated in the transfer case and a rear differential lock for the reinforced rear axle. A rotary switch in the centre console enabled the driver to engage the differential locks or select an automatic mode which activated the centre lock whenever required. Both differential locks could provide a 100 per cent locking effect;
• A modified version of the Airmatic air suspension which could increase ground clearance to 291 mm (an increase of 110 mm) and the vehicle’s fording depth to a maximum of 600 mm; and,
• A steel under-ride guard.

Body and dimensions

Unlike the ladder frame chassis of the Mercedes-Benz W163 M-Class , the W164 M-Class had unitary body construction. The W164 M-Class also had a significantly stiffer body, in part due to:

• a five-fold increase in the proportion of high-strength alloys; by body weight, 62 per cent of all body panels were made of high-strength steel alloys, including dual-phase steel; and,
• a continuous frame structure in the roof area (a ‘D-ring’) which was formed a connection between the side walls, floor and rear roof frame.

Compared to the W163 M-Class, the W164 M-Class was 193 mm longer (at 4780 mm), 78 mm wider (1911 mm), 8 mm taller (1815 mm) and had a 95 mm longer wheelbase (2915 mm). Furthermore, the W164 M-Class had a drag coefficient of 0.34 Cd, while rear axle lift was reduced by 70 per cent (to 0.033 cRA). Cargo capacity with the rear seats in position was 551 litres, though this increased to 2050 litres when the rear seats were folded flat.

Suspension

The Mercedes-Benz W164 M-Class had double wishbone front suspension in which the upper wishbone was made of forged aluminium and located in a high position, while the lower wishbone and steering knuckle were made of nodular cast iron. To reduce vibrations, four rubber bearings were used to isolate the front subframe from the vehicle body. Compared to the W163 M-Class, the spring struts had longer travel and more effective rubber bearings for greater ride comfort. The spring struts contained cylindrical coil springs, single-tube gas-pressure shock absorbers and large head bearings; a torsion bar stabiliser was attached to the spring strut by a linkage.

The rear axle was mounted on a subframe that was isolated from the body by two rubber bearings and two hydro-mounts. The W164 M-Class’s four-link suspension consisted of:

• A lower wishbone made from nodular cast iron;
• An upper steering arm that was an assembly of sheet steel camber arms and forged steel rods; and,
• Track rods that were located behind the wheel centres and of welded tubular construction.

The rear axle coil springs and single-tube shock absorbers were positioned in line; a torsion bear stabiliser was also used.

AIRMATIC and Adaptive Damping System (ADS)

The Mercedes-Benz ML 500 was fitted with a road-going version of Mercedes-Benz’s AIRMATIC air suspension system which could lower the suspension by 15 mm at higher speeds to reduce wind resistance.

The W164 ML 500 was also fitted with Mercedes-Benz’s ‘Adaptive Damping System’ (ADS) which controlled shock absorber response based on road surface, driving style and wheel loads via electronically-controlled solenoid valves that modified rebound and compression damping. The variable ADS gas-pressure shock absorbers and air springs were integrated into a spring strut at the front axle and, for the rear axle, located behind the air spring. ADS could select from four damping maps:

• Stage 1: soft compression and rebound settings for comfort;
• Stage 2: Skyhook mode for soft rebound setting and a hard compression setting;
• Stage 3: Skyhook mode for soft compression setting and hard rebound setting; and,
• Stage 4: hard rebound and compression settings to reduce wheel load fluctuations when cornering at speed.

When body movements were small, the M-Class would select Stage 1. If body acceleration values exceeded a threshold, the solenoid valves would continuously switch between stages 2 and 3 to compensate for roll and pitch. The driver could influence the changeover thresholds between the four ADS stages, as well as the spring rate, by pressing a button in the centre console. The driver could also select from Auto, Sport and Comfort modes.

Steering

The Mercedes-Benz W164 M-Class had variable ratio, rack-and-pinion steering with speed-sensitive power assistance.

Safety equipment

Standard safety equipment for the Mercedes-Benz W164 M-Class included dual front airbags, front and rear side airbags, full-length curtain airbags, ABS, electronic brake force distribution, brake assist, electronic stability control, traction control, active front seat head restraints and pre-tensioners and load limiters for all seats.

The W164 M-Class was also fitted with Mercedes-Benz’s ‘Pre-Safe’ system, which anticipated and prepared for collisions by tensioning the seatbelts, adjusting the seat positions for optimal airbag deployment and closing the sunroof (if open).

Brakes

The six-cylinder W164 models (i.e. the ML 280 CDI, ML 320 CDI and ML 350) had 330 mm by 32 mm internally ventilated front brake discs and 330 mm by 14 mm solid rear discs. The ML 500, however, had 350 mm by 32 mm front discs and 330 mm by 22 mm rear discs, with both front and rear discs internally ventilated.

Features: Mercedes-Benz W164 ML 280 CDI, ML 320 CDI and ML 350

Standard features for the Mercedes-Benz W164 ML 280 CDI, ML 320 CDI and ML 350 included 17-inch alloy wheels, an eight speaker Audio 20 sound system with a six-disc CD player, dual-zone climate control air conditioning (‘Thermatic’), power adjustable front seats, cruise control, front and rear fog lights, front and rear parking sensors, automatic headlights, rain-sensing wipers, a steering column gearshift lever (‘Direct Select’), a leather-wrapped steering wheel with gearshift buttons, 60/40 split and folding rear seats, remote central locking, power windows and heated mirrors, a tilt and reach adjustable steering wheel, cargo cover, trip computer, tyre pressure monitoring and an immobiliser.

The Luxury variants of the ML 320 CDI and ML 350 were further equipped with leather upholstery, additional power adjustment for the front seats, ambient lighting, a compass and choice of burr walnut or anthracite poplar interior wood trim.

Features: Mercedes-Benz W164 ML 500

The Mercedes-Benz W164 ML 500 Luxury was distinguished by its added 18-inch alloy wheels, Mercedes-Benz’s COMAND APS (Cockpit Management and Data Auto Pilot System) with a twelve speaker sound system and satellite navigation, four-zone climate control air conditioning (‘Thermotronic’), multi-contour front seats, an electrochromatic rear view mirror, electrochromatic and folding door mirrors, front seat memory settings, a power adjustable steering column and cargo net. With the introduction of the 5.5-litre V8 in October 2007, the ML 500 Luxury gained 19-inch wheels, a reversing camera and directional bi-xenon headlights with washers.

August 2007: M-Class update

In August 2007, the M-Class range underwent a minor update as the ML 280 CDI was fitted with ‘Artico’ synthetic leather upholstery and power adjustable front seats. The ML 320 CDI and ML 350 were also fitted with an off-road ‘styling package’ as standard and were offered with a choice of two ‘Luxury Packages’:

• The first Luxury Package consisted of 19-inch five-spoke alloy wheels, leather upholstery, power adjustable front seats with driver’s seat memory function, power adjustable steering column, Thermotronic multi-zone luxury climate control, anti-glare interior and exterior mirrors, folding mirrors, burr walnut interior trim, blue tinted glass, extended interior lighting, dark tinted tail-lights and a compass; and,
• The second Luxury Package consisted of Artico synthetic leather/Alcantara upholstery, power adjustable front sports seats, driver’s seat memory function, a power adjustable steering column and brushed aluminium pedals with rubber studs.

The ML 500 gained a reversing camera, directional bi-Xenon headlights and ‘exterior sports package’.

2008 Mercedes-Benz W164 ML 350 and ML 320 CDI Edition 10

In May 2008, limited-run ‘Edition 10’ ML 350 and ML 320 CDI models were released; these were distinguished by their 20-inch five-spoke alloy wheels with a titanium finish, COMAND APS system with satellite navigation, reversing camera, two-tone leather upholstery, directional bi-xenon headlights with washers, power sunroof, black fabric roof lining, sports instruments, aluminium pedals, ‘Edition 10’ floor mats, blue-tinted glass, twin-split chrome tailpipes and a titanium-finished grille.

Review: Mercedes-Benz W164.II M-Class (2008-11)

Overview

Released in October 2008, the Mercedes-Benz W164 Series II (W164.II) M-Class featured an updated interior, revised styling and improved equipment levels. Visually, the W164.II M-Class could be identified by its updated headlights, larger grille, ‘smoked’ tail-lights and integrated rear bumper reflectors. Inside, there was a two-tone colour scheme, new four-spoke steering wheel with gearshift paddles and upgraded audio and telematics systems. Occupant protection was also improved with more advanced active front seat head restraints.

Safety equipment

Compared to its W164.I predecessor, standard safety equipment for the Mercedes-Benz W164.II M-Class was improved with the introduction of a driver’s knee airbag.

Euro NCAP crash testing

In Euro NCAP crash testing , a Mercedes-Benz W164.II ML 320 CDI received a five star adult occupant protection rating with a score of 33.97 out of 37. In the frontal offset impact test, there was a slight risk of serious chest injury and leg injury for front occupants. Maximum points, however, were awarded in the side and pole impact tests.

Features: Mercedes-Benz W164.II M-Class

Compared to its predecessor, the W164.II ML 280 CDI gained 18-inch five-spoke alloy wheels, an Audio 20 sound system with six-disc CD player and auxiliary inputs, MP3/WMA/ACC compatibility, UCI media interface, five-inch colour monitor and Bluetooth connectivity.

The ML 350 Luxury and ML 320 CDI Luxury also received five-spoke 19-inch alloy wheels, power adjustable front passenger seat with memory function, reversing camera, ‘Artico’ synthetic leather dashboard trim, COMAND APS interface with a 6.5-inch colour monitor, DVD-based satellite navigation navigation, 4GB hard drive for music storage, SD card slot and voice recognition (‘Linguatronic’). Furthermore, the ML 500 Luxury Sports was fitted with five-spoke 20-inch alloy wheels and a power sunroof.

October 2009: M-Class update

In October 2009, the M-Class range underwent a minor update, as the ML 280 CDI and ML 320 CDI were discontinued and effectively replaced by the ML 300 CDI. AMG Sports variants were also introduced for the ML 300 CDI, ML 350 and ML 350 CDI models.

2011 Mercedes-Benz M-Class Grand Edition

In June 2011, Grand Editions were released of the ML 300 CDI, ML 350 and ML 350 CDI models. Compared to their standard counterparts, the Grand Editions were fitted with ‘Neck Pro’ front seat head restraints and featured 20-inch ten-spoke bi-colour alloy wheels, COMAND APS (6.5-inch colour display, DVD-based satellite navigation, six disc CD/DVD player, 4GB hard-drive and voice recognition (‘Linguatronic’), heated front seats, ‘Easy Pack’ power-operated tailgate, ambient lighting, AMG steering wheel with gearshift buttons and blue-tinted thermal insulating glass.

Visually, the Grand Editions could be identified by their daytime LED running lights, black gloss AMG grilles with chrome highlights, darkened LED tail-lights and metallic paint finishes. Inside, there was ‘Artico’ trim for the seats, door panels, armrests and upper dashboard, ‘Anthracite’ poplar wood trim highlights with chrome inserts, Designo black fabric roof lining and stainless steel door sill panels.

Brochures

• Brochure: Mercedes-Benz W164.II M-Class (International) (September 2009)
• Brochure: Mercedes-Benz W164.II M-Class (International) (February 2010)

Related links

• Press Kit: Mercedes-Benz W164.II M-Class (October 2008)
• Wikipedia.org: Mercedes-Benz W164 M-Class