USA 2014 GLK250 trip fuel economy experience
Just purchased a slightly used GLK250 with a bit over 7,000 miles and took it on a trip through the Rocky Mountains of Colorado including the Colorado Plateau of Northern Arizona and Southern Utah. Altitudes ranged from about 4,000 to over 12,000'.
9,004 miles resulting in 38.99 MPG. That is not a typo, 39MPG.
Some testing with the instantaneous MPG indicator explained it. Driving on a level road at 65 MPH pinned the indicator at 40 MPG. Increasing to 75 dropped it to 33. Repeated the test several times for consistency and used the cruise control to maintain speed. This engine falls off its thermal efficiency curve very rapidly.
Side notes:
1. While not as good overall, it achieves much better fuel economy going uphill than our 2009 Camry hybrid. On a similar trip the Camry got 41.4. The GLK will get 30 on a hill that drops the Camry below 20.
2. On the long climb from Frisco to the Eisenhower Tunnel, cruise control set to 60 mph, it stayed in 7th gear at 1,600 rpm. Our 2001 ML430 bounces between 3rd and 4th, I usually just hold it in 3rd (5 speed automatic). The ML has 31" tires or it might handle it in 4th.
Just FYI.
Wonder what the GLA will get when they add the diesel?


My runs near home are much shorter and sometimes involve city traffic. With a lot of the latter I've gone as low as 32-33 mpg.
-Pure city driving [less than 5% of the time for us]: 26 mpg
-Suburban grocery / doctor / shopping runs: 31-32 mpg
-Long highway trips [70-75 mph average]: 35-37 mpg
I couldn't be happier - our '10 gasoline GLK strained to deliver 23-24 mpg on trips.
And yes, restraining speeds to around 65 mph will indeed return consumption figures near 39-40 mpg. We've averaged 39 mpg a couple of times under favorable conditions.
The fact that most of CO is @ altitude is also a further plus for TDI operation. So for example, Denver is at app 5,280 ft.
Last edited by Rdub; Oct 14, 2014 at 10:42 AM.
We recently took position of a 2014 GLK250 with 29,300 km (18,200 miles) & have only fuelled up 3 times so still learning what the average will be.
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Normal city driving is a bit higher, around 29 mpg, but using the instant mpg reading on the highway, it frequently drops at or around 47 mpg.
Great for a 4 500lb SUV.
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