romivas

Hey all, my 2020 GLC is the first new car I've owned so I just want to make sure this is normal...

It's around a week and a half old and about 940 miles on it (bought it in LA area, took it to Palm Springs for vacation, and drove it back up to the Bay Area). When I fill up the tank, I get a range of about 415mi and my average mileage right now is 23.8 mpg even with having driven mostly highway. On my long drives, I was getting about 26-27 mpg.
My MIL's 2018 Q5, which just hit 20,000 miles, got a range of 515mi last time we filled up but its capacity is only 1 gal more than the GLC. Will these numbers go up as the engine breaks in with more time and miles?

Additionally, anyone have any tips on 'breaking in' new cars or any tips and tricks for the GLC specifically?
Thanks in advance!

GLK63AMG

I assume you reset the trip to get the pure statistics from the trip to include just the highway miles. How fast were you driving? Anything above 55 mph you start to lose efficiency and anything above 65-70 the effect is greater. I drove 1,200 miles on my ‘20 GLC with speeds around 75-80 and got 22.6 mpg. I think to get closer to 28mph highway you have to drive slower

ajmtbm

On a 2017 I pretty regularly get 29 - 31 mpg on a 50 or so mile trip mostly highway, travelling right around speed limit with Distronic typically on most of the trip. Haven't seen much difference in mileage between C or E mode on the trip. That is what the car is telling me, never really validated how accurate it was

GLK63AMG

How fast are you driving?

ParjAS

I manage 29-32 on the highway in E with cruise on at 55-60, no Distronic. I have 4matic as well. Managed a high of 36 after a steady 45 mph drive along a bunch of country roads.

romivas

I've never actually 'reset' a trip but I've noticed that MBUX automatically does that every few drives (I have the digital cockpit so I'm not sure if it does it for the analogs too). My biggest concern with the initial post was that the range when filling up the tank was significantly lower then that of my mother-in-law's Q5 and I was hoping that it would get better with time.

So far, the max range I've gotten is 420mi on a full tank. It has gone up to around 440mi if I hop on the highway right after I fill up.

wkc987

I think the 2018 Q5 uses quattro ultra, which is a system that uses front wheel drive in most of the time and awd when needed.
It will be a fair comparasion if you compare the fuel consumption on both and from my experiences, those ranges usually is calculated from the fuel consumption.

mikapen

The range showed on your display is based on the most recent driving style you used. If you raced to the gas station, you will see a lower estimated range than if you dawdled.
I get about 32mpg under 70 steady cruising, but it falls to @24 if I am cruising above 85.

I also find that Distronic costs about 3-4mpg.

romivas

Oh thanks for the tip, I didn't even consider the differences in driving systems with the Quattro.

romivas

Yup that's about what I'm getting too on highways now. I don't have Distronic but I do also tend to lose a few mpg with regular cruise control.

High Technology

FWIW, I was surprised that the 2020 GLC didn't provide better MPG. I only had it for a few weeks pre-COVID (where I drove ~300 miles a week, about 3/4 that being highway 65 MPH) and was getting around 24/25mpg on my weekly fill-ups. I found this surprising since I came from a 6-Cylinder Acura RDX AWD (roughly same size / likely same weight class), where I routinely got 27 MPG. Heck my wife's Dodge Durango (which is probably 1/3 larger/heavier) gets 23/24MPG on the highway (and only about 1 MPG less than the GLC in that mostly highway driving routine).

I just figured with the 4-Cylinder I'd get closer to 30MPG, and didn't expect to go down to 25MPG. Since mine was a demo with ~3k on it, initial break-in wasn't a consideration. I thought the whole point of all of these 4-Cyl engines was to meet the Corporate Average Fuel Economy (CAFE) requirements...

mikapen

What octane fuel do you use? % ethanol? Winter blend?

ParjAS

With a turbo, it is power vs. efficiency, you can't have both.

eddieo45

my wife has only been driving the GLC for a few days but yesterday was her first day with a fair amount of driving: a combination of traffic into her office in the city and a long highway ride for a lunch meeting. she reports about 19.4 MPG, far less than she was used to in her C300, which I believe has the same engine. I typically get 30 MPG in my SL400, a twin turbo 6 cylinder of nearly the same weight.

Tuckahoe Mike

To add another data point, my GLC300 gets about what the new car window sticker said: 21mpg city, 28mpg highway, 24mpg combined. I always use 93 octane gas with state mandated 10% ethanol. Also always use the Driver Assistance Package including the DISTRONIC. Also occasionally use ECO Dynamic Select Switch rather than the usual Comfort mode. That can boost highway mileage a few mpg's above 28. Pretty satisfied with mileage.

mikapen

Yet another data point.
Are 2019 GLC 300 4matic gets 29 to 30 on the open road, averaging 65 mph. Slower speeds (steady 65) gets us in the low 30s.
A full tank of premium with only in town driving, gets about 23 or 4.
That's based on calculations at fill up, not the average shown in the car, although that displayed mileage is usually plus or minus one MPG.

I wonder if the OP did actual calculations, or read the display, which can be wildly optimistic.

mikapen

Very similar to our experience at 5,000 FT elevation.