30 MPG - Is it OK?

[dad4geer]

C 180 W204 Petrol (1.8) - It's been more than a month I have been driving it and to find out exact MPG figures I noted down mileage when filling up full tank and just today filled it again full tank. It did about 350 Miles in about 11.5 Gallons, comes out roughly 30 MPG. Most of my drive was to and from work on a B Road, rat run to town centre for groceries etc. and just one trip to Oxford on A34/M4. This is my first MPG calcluation and I will be doing more to get a more precise average. My question is that are these figures normal for my car? I think I should have got at least 35-37 MPG so does it need any tuning or anything else to improve its MPG. It had a D service from Merc Benz before I bought it (August).

 

[David404]

I'd suggest logging miles and fuel added for 4 to 5 full tanks before drawing conclusions about MPG. over one tank full its easy to get variation in fill levels or other unusual circumstances to throw result accuracy.

double check your conversion factor litres to gallons - make sure you use imperial (UK) or US gallons as appropriate they are different and specify which you are reporting in when posting to avoid confusing those of us on the east side of the pond in the UK.

Try www.fuelley to keep track (its free) and/or app on smart phone.

 

[steve333]

I've previously owned a c180 k and the wife an slk230k and currently she has an slk200k and all average somewhere around 30 mpg over a tank of mixed driving-merc 4 pot petrol autos are really not very economical IMHO.....

 

[geraldrobins]

Very difficult to say without knowing your driving style, journey length, amount of traffic etc. But 350 in a month isn't much so your car may not be fully warmed so not ideal for fuel consumption. Is it an auto? Im currently achieving 45 mpg on shortish runs mainly, as I am almost retired. According to the official figures your mpg is 75% of mine so maybe yours is about right.

 

[David404]

should have read the post more carefully, see its obvious you are in the UK.

1 (Imperial UK) gallon = 4.54609 litres

 

[dad4geer]

should have read the post more carefully, see its obvious you are in the UK.

1 (Imperial UK) gallon = 4.54609 litres

Thanks David.. Yes I used this conversion to convert Litres to gallons.. was Oxford, A34 and M4 were not obvious?

Thanks for pointing me towards that fuelly app, I was using an excel file

 

[dad4geer]

Very difficult to say without knowing your driving style, journey length, amount of traffic etc. But 350 in a month isn't much so your car may not be fully warmed so not ideal for fuel consumption. Is it an auto? Im currently achieving 45 mpg on shortish runs mainly, as I am almost retired. According to the official figures your mpg is 75% of mine so maybe yours is about right.

Yes it's an Auto 7G tronic (722.9). Work is 24 miles drive in total (to and from home) on a B Road and yes I drive straight away in morning or leaving work so obviously it does not get that warm. Most of the time I drive around 40-50 MPH speed but love to put my foot down when the road is clear and have done this quite few times (loved the way it picks up speed). As this is my first MPG figure I may have to get some more on this but thought to get some idea if the figures are a bit of a concern...

 

[190]

Not quite the same car but my 2009 W204 C180K BE with manual box would get 45MPG in the use you have described assuming no standing traffic. The worst I had over a fill is 37 MPG and that was just once with all shortish trips in the winter. Every other fill has been 40 MPG or above with a best of 57 MPG. All properly measured although the displayed MPG is accurate to within 2%. I don't doubt I could get mine down to 30 MPG if I flogged it to death up hills and did no steady cruising.

You haven't given the model year but I assume it must be face lift model if is has a 7 speed auto. That being the case the auto box shouldn't make much difference or at least that's the theory, so for me 30 MPG is not right.

 

[gIzzE]

Sounds a bit low, I have a 3.5 V6 petrol E Class estate with winter tyres fitted with the 7g 'box and I average 30mpg and get 35+ on that sort of run.

Does your thermostat get to 90ºc within a mile and stay there no matter what?
These cars can go through 'stats pretty quickly and if they are under reading they can drink a lot more fuel.
Having said that, tank before last was 31mpg on my E350 and the one this week was 27.7 and it was pretty much identical driving, so could be temperatures have dropped?

 

[sirius9]

Which year W204? Kompressors or Blueefficiency ones?
If C180 Kompressor W204, 30-32mpg about right.
Depends on whether u drive in C or S mode.
Had mine for 6 years now n averaging 31mpg over 70k miles.

 

[MancMike]

It depends too much on the style of driving and journey.



Your 3.5 is the M276 isn't it? The later CGI models which get far better power and economy than the non-CGI like mine.

My 3.0L Petrol V6 has averaged 21mpg over the last 5,000 miles. I rarely do journeys over 12 miles long and like to give it the beans whenever possible, so I'm happy with my 21mpg.

 

[gIzzE]

Yeah, it is the later cgi, have to say, most petrols I have owned have been about the same no matter what size if they were from the same era.

I owned a 318i and got 28mpg, then owned a 330i and got 27mpg.
I owned an E39 528i and got 21mpg from it, and the E36 320i 4cyl they lent me for a fortnight got exactly the same 21mpg as the 2.8 6cyl.

So maybe 30ish is about right from his C180.

 

[french]

Its quite a heavy body for an under powered engine & the final drive might be short...what does it show revs wise @70mph ?

In answer to the title of this thread 29 mpg in a E55 AMG supercharged is amazing ...30mpg from a 1.8 is dire.