Premium large SUV; Built in USA
  • 4-door wagon
  • longitudinal front-engine/all-wheel drive
Good condition price range: $25,000 – $75,000*

2008 Mercedes-Benz GL-Class

2008 Mercedes-Benz GL-Class

2008 Mercedes-Benz GL-Class

2008 Mercedes-Benz GL-Class

  • Acceleration (V8)
  • Cargo room
  • Climate controls
  • Interior materials
  • Quietness
  • Seat comfort (front)
  • Fuel economy (V8)

Measured against most premium large SUVs, the GL-Class comes up short in outright passenger and cargo space. Even so, interior accommodations are more than adequate for the majority of buyers, and relatively trim exterior dimensions ease parking and maneuverability. Impressive power and high levels of refinement seal this SUV’s Recommended status. Availability of a relatively frugal diesel model is another mark in Mercedes’ favor.


Mercedes-Benz’s newest sport-utility vehicle was essentially a stretched version of its midsize five-passenger ML-Class wagon. Both used car-type construction, but the GL seated seven, weighed some 500 pounds more, had more towing capacity, and offered more available off-road equipment. First up was the GL450 with a 335-horsepower V8 engine and seven-speed automatic transmission, with steering-wheel controls for manual operation. All-wheel drive was standard. An optional off-road package added low-range gearing plus locking center and rear differentials, and allowed up to 2 inches of additional ground clearance. During the 2007 model year, Mercedes-Benz launched a GL320 CDI with a 215-horsepower turbodiesel V6 engine.

Antilock braking, traction/antiskid control, hill ascent and descent control, and a height-adjustable suspension were standard. So were front side airbags and curtain side airbags that covered all seating rows and included rollover deployment. Options included leather upholstery, a navigation system, DVD entertainment, front and rear obstacle detection, and keyless ignition. Also available were steering-linked xenon headlights, and Mercedes’ Adaptive Damping suspension that included driver-selectable firmness settings. Gasoline-engine GL-Class rivals included the Audi Q7 and Cadillac Escalade.

Yearly Updates

2008 GL-Class
A new flagship model with a bigger engine and exclusive styling touches joined the GL450 and GL320 CDI for 2008. Named GL550, the new model contained a 382-horsepower V8 and had a unique front-end appearance, flared fenders, chrome exterior accents, and 21-inch wheels. Standard features on the GL550 included leather upholstery, a navigation system, rearview camera, and steering-linked headlights.
2009 GL-Class
A new BlueTEC diesel engine, rated at 210 horsepower, went into the GL320 BlueTEC, which replaced the GL320 CDI. This new diesel model was fitted with run-flat tires and was sold in all 50 states.
2010 GL-Class
The 2010 Mercedes-Benz GL-Class received freshened styling.
2011 GL-Class
The 2011 Mercedes-Benz GL-Class was largely unchanged.
2012 GL-Class
There were no significant changes to the Mercedes-Benz GL-Class for 2012.


longitudinal front-engine/all-wheel drive

In the GL450, a 4.7-liter V8 develops 335 horsepower, mating with a seven-speed automatic transmission. The GL550 gets a 382-hp, 5.5-liter V8. Mercedes’ GL320 CDI uses a 3.0-liter turbodiesel V6, also with the seven-speed automatic. That engine was changed slightly for 2009 to become the GL320 BlueTEC. All GL models have all-wheel drive.

Turbodiesel dohc V62
Engine Size (liters/cubic inches) 3.0/182
Engine HP 210
Engine Torque (lb-ft) 398
Avail. Trans. EPA MPG (city/hwy) MPG avg. as tested
7-speed automatic



Turbodiesel dohc V61
Engine Size (liters/cubic inches) 3.0/182
Engine HP 215
Engine Torque (lb-ft) 398
Avail. Trans. EPA MPG (city/hwy) MPG avg. as tested
7-speed automatic


dohc V81
Engine Size (liters/cubic inches) 4.7/265
Engine HP 335
Engine Torque (lb-ft) 339
Avail. Trans. EPA MPG (city/hwy) MPG avg. as tested
7-speed automatic



dohc V81
Engine Size (liters/cubic inches) 5.5/333
Engine HP 382
Engine Torque (lb-ft) 391
Avail. Trans. EPA MPG (city/hwy) MPG avg. as tested
7-speed automatic


1. EPA Note: Figures shown are for 2008 models. The Environmental Protection Agency changed its procedure for 2008 to yield more realistic estimates. Therefore, estimated mileage is lower than for prior years. 2. GL320 BlueTEC.

Road Test

In the GL450, a potent engine and smooth, alert transmission combine for effortless power delivery. Even more performance hails from the GL550. While the GL550 produces greater punch, the GL450 is plenty strong for any task. A GL320 CDI can feel slightly lethargic at takeoff, and some testers would have preferred quicker highway passing response. Yet, the turbodiesel V6 never feels underpowered. Every GL has 7500-pound towing capacity.

Fuel economy with gasoline engines isn’t the best. A test GL450 averaged 15.2 mpg in a mix of city and highway driving. GL450/550 models require premium-grade gasoline. The GL320 CDI requires ultra-low-sulfur diesel fuel and has not been sold in California and certain Northeastern states.

Impressively compliant over bumps, the GL320 CDI and GL450 with 18-inch tires are subject to unwanted body motions that compromise ride comfort. Models with optional 19-inch tires (or the GL550 with 21-inch) cannot absorb sharp ridges without some jarring. All models are stable at speed, but they sway and rock significantly on uneven surfaces.

Steering has direct, accurate feel, which imparts a somewhat sporty character. In fast turns on smooth surfaces, the GL550 has tenacious grip and relatively little body lean, but all GLs stay flatter in corners than most large SUVs. However, the GL550 tends to “tramline” along channels in the road and can skitter sideways on bumpy corners, compromising the sure-footed security of all other GLs. Stopping control is good, but brakes on one test GL450 suffered mushy feel and long pedal travel.

GL is among the quietest premium large SUVs. Wind rush is nearly absent; road noise is well controlled. Engines emit a refined, rewarding full-throttle growl, but is otherwise well muted. Even the diesel model is quiet at cruise. The GL550 exhibits more tire noise than others, along with a prominent exhaust note.

Gauges are large and easy to read. Most controls are logically placed, and most adjust with a weighted, precise feel; but some have cryptic markings. Mercedes’ navigation system absorbs most audio functions, complicating their use. Gear changes are accomplished via a short steering-column lever with an unfamiliar toggling action. High-quality materials, including genuine wood trim, give the cabin a premium feel, though the conservative design may appear too austere to some.

Front occupants get ample headroom and legroom, though the cabin does not feel notably spacious. Seats are supportive and generously sized. Entry and exit are easy via large doors and no-stress step-in height. Visibility is good, but over-the-shoulder views for lane changing are hindered by small exterior mirrors.

Most rivals are larger overall, so GL’s rear-seat accommodations suffer by comparison. Outboard passengers have ample headroom and legroom, plus good seat support. But the relatively narrow cabin and low-hanging ceiling vents limit the center position to occasional use. The third row is best suited to children, though smaller adults will fit in a pinch. Only the right-side section of the second-row bench seat slides forward for third-row access, though it does create a large passageway.

Cargo volume is restricted to a few grocery bags with the third row in place. Low floor height and second- and third-row seatbacks that fold flush with the deck ease loading and unloading. Relatively tight dimensions limit overall volume, however, and the rounded hatch opening curtails cargo-item size. Numerous cabin-storage areas are available, but none are generously sized.


Model Tested: 2008 GL450

Ratings values are on a 1-10 scale, with 10 being the best. With the exception of Value, these numbers reflect how the vehicle compares against the universe of vehicles, not just against rivals in its class.


Acceleration - 6
Fuel Economy - 3
Ride Quality - 6
Steering/Handling - 5
Quietness - 8


Controls/Materials - 6
Room/Comfort Front - 8
Room/Comfort Rear - 7
Cargo Room - 9


Value - 7

Total: 65


4-door wagon
Wheelbase (in.) Length (in.) Width (in.) Height (in.) Weight (lbs)
121.1 200.6 76.0 72.4
Cargo Volume (cu/ft) Payload Capacity (cu/ft) Fuel Capacity (gal.) Seating Capacity
83.3 26.4 7
Headroom Legroom
Front Rear Front Rear
40.1 40.6 43.0 40.0
Safety Ratings

Model Tested: N/A


(5 is the highest rating)

Front Impact Test

Driver Injury - N/A
Front Passenger Injury - N/A

Side Impact Test

Driver Injury - N/A
Rear Passenger Injury - N/A


(A score of 100 is average. Lower is better)

Collision N/A
Injury N/A
Theft N/A

Trouble Spots

Climate control
Description: The climate control system may begin working poorly when it is snowing unless a revised fresh air intake grille has been installed. (2007-08)
Fuel pump
Description: Fuel may leak from the low-pressure hose fitting in cold weather or high-pressure fuel pump on the diesel engine. (2007-08)
Steering problems
Description: The speed sensitive power steering may quit working due to a faulty solenoid on the rack-and-pinion assembly. (2008-09)
Description: The sunroof may reverse direction while closing if it drags the sun shade along which causes too much resistance which may require replacement of the sun shade. Also water may leak into car from sunroof if drain hose is misrouted. (2008-09)
Fuel economy
Description: Drivability problems, poor fuel economy and engine knock can all be due to a bad fuel pressure regulator on the 3.0L, V-6 turbo-diesel engine. (2007-08)
Description: The rear power tailgate may quit working due to a failed control module. (2008)
Description: The onboard garage door opener may not work or may not pair with a hand-held remote due to having been programmed by previous owner requiring erasure of previous code(s). (2008-09)
Description: A warning of low oil level or to add oil at the next stop, although the oil level is fine on the dipstick, may be due to the wrong dipstick, a faulty oil level switch of software error. (2008-09)
Check-engine light
Description: The check engine light may illuminate and a code may be stored for a problem with the secondary air injection system on the V-8 gasoline engine, but reflashing the control module usually fixes it. (2007-08)
Check-engine light
Description: Wires in the right (passenger) foot well can get caught in the battery cover and damaged which triggers the check engine light. (2008-09)

Recall History

2006-08 GL-Class with trailer hitch
Description: Some of the weld seams connecting the trailer-hitch receiver to the attachment bar used to secure the trailer hitch to the body frame do not meet performance specifications. This may result in the trailer-hitch receiver separating from the attachment bar. The trailer hitch must not be used for any purpose until it has been repaired. Dealers will repair the trailer hitch.
2007-08 GL-Class diesel
Description: Engine may stall and not restart due to a failed crankshaft sensor. Dealers will replace the crankshaft sensor.
2008 GL-Class
Description: Defective driving pin, used to control oil pressure of power steering, could break during normal turns, limiting steering-wheel operation.
2011 GL-Class, model X164
Description: The O-ring may not have been properly lubricated in all cases. Lack of lubrication can lead to leakage of the fuel filter. Diesel fuel may be deposited on roads and making those roads slippery, increasing the potential for a crash. Dealers will replace the fuel filters free of charge.
2011 GL-Class diesel
Description: Diesel fuel filter may leak from around the heating component onto the road surface.

Equipment Lists

Equipment lists are only viewable on larger screen sizes.


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