Before the 2013 GLK went on sale, there was a buzz surrounding this vehicle. We had heard it was going to be powered by a diesel engine, a smaller-displacement one than the 3.0-liter V-6, which is available in the M- and GL-Classes as well as the Sprinter. We even got to drive a Euro-spec GLK diesel and were thoroughly impressed with the engine and how it works with this vehicle. Yet you never know for sure if something is going to change in the translation -- when we learn we're getting a version of a European drivetrain from any automaker, there's always the possibility that we'll get a detuned version, lower on horsepower and/or torque because of fuel-economy goals, emissions regs, etc. But Mercedes didn't let us down. The U.S.-spec GLK with the BlueTEC engine has just as much oomph as the Euro model we tried last year.

We got to sample the GLK on canyon roads and freeways in Southern California. The GLK was updated for the 2013 model year, with a new interior, redesigned front end, new wheels, more safety features, more horsepower and torque in the 3.5-liter V-6, and, of course, the new engine. While the rear-drive GLK350 continues on as the base model, when equipped with the 2.1-liter inline-four (only sold with all-wheel drive), the GLK250 is priced below the GLK350 4Matic. The engine packs a punch, too: the twin-turbo diesel provides 200 hp, and a fantastic 369 lb-ft of torque. While the V-6's 302 hp eclipses that of the 2.1, the four-cylinder offers almost 100 more lb-ft of torque, at a significantly lower rpm.

We immediately noticed the influence of the torquey diesel, but it wasn't from hearing it. The GLK's cabin has plenty of sound-deadening material, and the engine provides a low rumble that's barely above a purr. You hear it more when outside the vehicle, but even then, it's quiet. However, it effortlessly gets the vehicle up to speed in a hurry, and the seven-speed transmission's shifts make excellent use of the power. At the track, the diesel GLJK got to 60 mph from a stop in 7.0 seconds, completing the quarter mile in 15.3 seconds at 87.4 mph. It took only 117 feet to stop from 60.

As good as the 3.5-liter is in the GLK, the 2.1-liter diesel feels like a total natural here. It offers tons more torque and better fuel economy (24 city, 33 highway versus 19 city, 24 highway for the GLK350 4Matic, 25 highway with the rear-drive GLK350), and does this without making buyers pay a high price for it. It also offers a whopping 515-mile range on a single tank of fuel. That's a lot for the money, and the combination of power and economy will be available for buyers without much of a compromise -- they simply have to fill up at a different pump. The only complaint we have is that the ride was a little harsh; the GLK didn't seem to absorb bumps and potholes. Considering the wilds of major cities will be where most people will drive these vehicles, this is something buyers will notice right away. But steering was responsive, and the Mercedes was a lot of fun in twists and turns.

Even when it comes to maintenance, buyers won't have to worry about refilling the diesel exhaust fluid. When an owner takes the GLK250 in for regular maintenance, the dealer will refill the AdBlue tank. For the curious, the AdBlue refill spot is located under the carpeting in the cargo area. This is the spot where the spare is stored in gas-powered GLKs. The GLK250 has run-flat tires instead of a spare tire.

Mercedes-Benz has been one of the strongest supporters of diesel engines in passenger cars, vans, and sport/utility vehicles, so it's no surprise that this company would be the first in this class to offer a diesel engine. Things will get interesting when Audi, another strong company in the diesel market, brings out a diesel-powered Q5. That one will be powered by a 3.0-liter turbodiesel, so it could be pretty quick, but Mercedes will have until model-year 2014 for that rival to arrive. And the Q5 likely won't have fuel economy as good as the GLK250. In the meantime, whether buyers are diesel fanatics or just want to get more power and more fuel economy for the money, the GLK250 is a solid choice.


A Second Opinion


Online Editor Edward Sanchez also spent some time in the GLK250. Here are his thoughts:

The driving experience of the GLK250 is quite different from that of the GLK350. Whereas the V-6 has a redline of 6800 rpm, the diesel's redline is rated at 5200, but venturing into that stratospheric realm is a rare occurrence, as even under aggressive throttle, the engine usually upshifts around 4500 rpm. On paper, the prospect of almost 400 lb-ft of torque in a small SUV seems like it would make for a thrilling ride, but the reality is a little more subdued. The GLK BlueTEC is far from gutless, as its 7.0-second 0-60 sprint attests. The experience is characterized more by a generous, steady swell of torque that wafts you up to speed rather than a frenetic high-rpm pull.

Naturally, there are other subjective differences in the character between the gas-powered and the diesel GLK. Rather than the V-6's sporty growl, the BlueTEC sounds exactly like you'd expect a four-cylinder diesel to, with a gravelly, staccato idle, and nonchalant thrum when driving. From the outside of the vehicle, there's no mistaking it's anything other than a diesel. If you listen closely, you get a little of the diesel character on the inside, but vibration and noise are adequately subdued where it doesn't spoil the upscale ambience of the interior or drive.

The BlueTEC's big payoff over the gasser is in fuel economy, and during its stay with us, the GLK returned an indicated combined average of 28 mpg, pretty much spot-on with EPA estimates. Stop-and-go driving around town returned an average in the low 20s, but highway cruising between 75-80 mph yielded a running average of between 30-33 mpg. Although the 2013 GLK350 has improved fuel economy over its port-injected predecessor, the MPG champ is still decisively the BlueTEC.

The big dilemma with diesels relative to their gasoline-powered counterparts has been cost, with the powertrain option alone usually adding several thousand dollars to the price of the vehicle. For drivers who put a lot of miles on their cars, the cost can be recouped by savings at the pump, but for short-term leasers or low-mileage drivers, diesels may seem less attractive. The GLK BlueTEC largely erases the pricing gap relative to the gasoline model, starting at $500 less than the starting price of a GLK350 4Matic. The BlueTEC is offered exclusively with 4Matic all-wheel drive, which is a $2000 option on the GLK350.


2013 Mercedes-Benz GLK250 Bluetec
BASE PRICE $39,495
PRICE AS TESTED $50,485
VEHICLE LAYOUT Front-engine, AWD, 5-pass, 4-door SUV
ENGINE 2.1L/200-hp/369-lb-ft twin-turbo DOHC 16-valve I-4
TRANSMISSION 7-speed automatic
CURB WEIGHT (F/R DIST) 4359 lb (54/46%)
WHEELBASE 108.5 in
LENGTH x WIDTH x HEIGHT 178.3 x 74.3 x 66.9 in
0-60 MPH 7 sec
QUARTER MILE 15.3 sec @ 87.4 mph
BRAKING, 60-0 MPH 117 ft
LATERAL ACCELERATION 0.74 g (avg)
MT FIGURE EIGHT 28.7 sec @ 0.57 g (avg)
EPA CITY/HWY FUEL ECON 24/33 mpg
ENERGY CONS., CITY/HWY 159/116 kW-hrs/100 miles
CO2 EMISSIONS 0.81 lb/mile