I imagine as a new car the mileage will be less than optimum. We have the GLC 300 and our MPG is 15mpg. Mostly city. maybe 82% city driving.

What mpg are you seeing?

 

We have the Australian-spec GLC 250. Have done about 2,000 miles on it so far and the gas mileage is still improving on every tank. I hope my math is right on this as we usually measure consumption in litres per 100km over here, but I believe we are now getting about 21 mpg. I would say about 70% city driving, 30% highway.

 

Just returned home after an approximately 800 mile trip. Averaged 28 mpg. Average speed 67 mph. Drove mostly with Distronics plus engaged.

 

Likewise, did 500-mile trip at 72 mph and 27.6 mpg averages.

 

Less than quoted by Mercedes!!!!!!!!!!!!!!!!
Average local commute around 35-40mpg (British) though the car has only done 2500miles so expecting more as she loosens up.

 

Ok, so filled up on the first tank of gas just about when the low fuel warning thing came up. . 15.48 gallons at 267.9 miles. So, 17mpg. I must have a golden foot (gold weighs more than lead -right?) hehe

 

So far 26 mpg.

 

Awesome.

 

31.3 via the GLC computer from Asheville NC to New Kent VA. 65-70 MPH

Around 25 mpg on the other fills.

 

Bear in mind that mist engines take several thousand miles to fully break in and reach full potential in terms of power and fuel efficiency.

 

24.7 miles mostly city driving. Still @1,200 miles since I bought it so should get better I guess

 

Man. I know I don't have a "lead foot" so it's not good that I get only 17 mpg. I do keep the air conditioner on all the time. But, that can't account for that bad an mpg.

 

26 mpg, about 40% city and 60% highway driving

 

With my petrol cars I put around 400ml ( can of coke) of mentholated spirits in the petrol tank to displace any water from condensation forming in the tank. That way the dissolved water is burnt with the petrol in the engine and you avoid any later contamination.
Additionally I do not let my tank get lower than 75% empty as most modern cars seem to use the fuel in the tank to keep the electric fuel pump in the tank cool ( sort of like a built in radiator).
Finally I regularly use a respected brand name fuel and injector cleaner in the tank, only when I fill the tank to full.
You might have a partly blocked injector and the engine management system might be compensating by loading the other cylinders to provide smooth operation.
Run a tank or two and repeat cleaning process and take it for a 50 mile drive or more to help clean the system.
Your GLC made in Europe ? Then had to be shipped by sea and sit whilst inspected, prepped, etc, so it's likely the tank was empty for 1 to 2 months before being filled for the first time.
Try my suggestion, if still no better I would suggest booking in for computer analysis of engine and transmission behaviour. Possibly auto is not running as effectively or there is an injector blockage, or engine sensor ( multiple sensors to choose) might be defective.
Good luck, let me know how you get on.
Cheers

 

Second long distance trip-500 miles. Average 26.2 mpg, 67 mph. Am very happy with this as my GMC Envoy on the same trip at similar speed would average about 17.5 mpg.

As Jeva posted earlier I expect the GLC fuel mileage to improve a bit as it gets broken in.

On the other hand...same trip with my ZO6 7litre V8, 610 hp, results in average 26.5 mpg at about 70 mph average.

 

That sounds awful low I'm assuming its a diesel, I have the older GLK 250 diesel and I don't think I could beat it hard enough to bring it down to 21 mpg....

 

i'm in Canada so we use liters/100km and I've done just under 200km so far and i'm currently averaging litters/100km 90%city driving

 

All these numbers are good to hear; I was quite worried after my neighbour told me I got a gas guzzler. It seems quite close to the advertised MPG, L/100km.

 

Try this table.
My 250d in Oz , usage approx 7.1 lt/100km, currently, with 80% city driving, travelled 3000km..

L/100 to UK = 1:282
L/100 to US = 1:235.
7.1 to UK = 39.8 mpg
7.1 to US = 33.2 mpg
See link = http://www.thecalculatorsite.com/con...onsumption.php
Cheers.

 

The first 425 miles, from full tank to full tank came out to 25.8 mpg by actual miles and gallons, doing the math. It was a mixture of heavy city traffic and highway.

Yesterday took a 130 mile trip, mostly highway, and the dash computer showed 32.2 "from start."

 

wow... better than the quoted 21 city / 28 hwy. How can this be?

 

A) those are EPA ratings and represents average consumption for the driving specified. Could be his driving was a lot of downhill or flat terrain.
B) the vehicle calculations are not always dead on accurate

 

Excellent point! Fuel economy will typically continue to improve over the first 10K miles. It's not unusual for a vehicle to reach peak fuel efficiency after a year or two of ownership.

 

Performance.
250d – drove today up into rural VIC , whole time on Western freeway, highway with some small town running around. Got back tonight, 350km, diesel ave 6.1 l/100. 3 adults, boot full, mostly mix of 110kph down to 40 and 60kph in roadwork areas.
Have travelled total of 4000km to date.
Great drive, very easy and quick to overtake at speed. Impressed.

 

Keep in mind these numbers are derived by a government agency performing a government test that is not much like how we actually drive our vehicles. When perusing the fuel economy numbers on the Monroney sticker its probably smart to take them with a grain of salt.