TomGator1

I've had my C350 for 3 weeks now. Here are a few things I have noticed with regard to fuel economy:

I have not reset the "Fuel Consumption Statistics Since Start" since I picked up the car. At first, it was showing 13MPG when the car had 20 miles on it. It has since steadily risen and is now at 21MPG after 650 miles and is still rising.

I also noticed that when I first started driving it, the "Fuel Consumption Statistics Since Last Reset" never went above 23MPG even trips of 40 miles and usually finished anywhere between 16-19 MPG. However, in the last week, I have seen readings of 27, 28 and 29 MPG final readings after 20, 30, or even 60 mile trips.

I am following the MB break-in guidelines for the first 1000 miles to a T. See page 310 of your manual (USA). It says:

The more cautiously you treat your vehicle during the break-in period, the more satisfied you will be with its performance later on.

Drive your vehicle during the first 1000 miles (1500 km) at varying but moderate vehicle and engine speeds.

During this period, avoid heavy loads (full throttle driving) and excessive engine speeds (no more than 2/3 of maximum rpm in each gear).

Avoid accelerating by kick-down.

Do not attempt to slow the vehicle down by shifting to a lower gear using the gear selector lever.

Select gear ranges 3, 2 or 1 only when driving at moderate speeds (for hill driving).

Select C as the preferred shift program (> page 144) for the first 1000 miles (1500 km).

After 1000 miles (1500 km) you may gradually increase vehicle and engine speeds to the permissible maximum.

BELIEVE ME - it has not been easy to follow these instructions!!! Especially staying in the C (Comfort) shift program most of the time. I can't wait to really drive it using the S (Sport) and -/+ modes! But I figured I'll baby the car for 1000 miles. It seems to be paying off in the MPG department as I can definitely tell the break-in period is working.

qwerty1024

Hi - someone had started a similar thread for the C300. There (https://mbworld.org/forums/c-class-w204/212954-c-300-gas-milage-fuel-economy.html) I've added some infor regarding the C350.

Funny how I am also finding it very hard to refrain from breaking the published "rules" for the 1000 mile break-in period!!! Glad to know I'm not the only one.

In the nearly 700 miles the C350 has accrued since purchase, one of the trip meteres (i think the one "since Reset", not "Since Start") indicates that the car has been averaging 22.8 miles per gallon. This is not as bad as it may seem considering that the averagge speed during the ~700 miles is A NOTORIOUSLY PATHETIC 38 MILES PER HOUR (lots of stop-and-go traffic).

I will reply to your thread with the avg fuel consumption, distance and avg speed once I get the data from car.

Can you share those values as well from the trip computer that's been reset the earliest?

MBTex

I plan on taking the car on a few 200+ mile road trips to get that first 1000 out of the way quickly.

Then I'll see what happens.....

TomGator1

Ok. Just checked my trip computer. Here's what it says:

770.7 miles on odometer
Since Reset:
770 mi (# of miles since reset - I haven't reset it)
21.5 mpg (avg. mpg)
27:24h (total # of hours:minutes driven)
28 mph (avg mph)

My avg mpg has improved by .5 mpg over the past 120 miles since I last checked at 650 miles. I'm pretty happy with 21.5 mpg with an avg mph of only 28. I've been stuck in a lot of traffic lately.

MBTex

Mileage will improve after the break in period....

qwerty1024

Thank for getting that data. Wow, I should stop complaining about traffic since you averaged 28 MPH. That, in my un-expert opinion, makes the calculated 21.5 MPG respectable for a C350.

Here's what this one has:And as everyone says, mileage will continue to get better (up to a point) after the break-in period. But I expect that to be offset, at least occasionally, by more aggressive driving. We shall see. Anyawys, I am personally not obsessed with the gas mileage - I would have gotten something else if that was my primary concern. Nonetheless, I find it interesting to see the distance one can sqeeze out of a US gallon of premium gas.

One one last comment: if and when there will be a direct injection engine available, for me, the improved gas mileage would be just as imporotant as the extra HP.

e1000

https://mbworld.org/forums/c-class-w203/199490-who-needs-prius.html

JimPap

Check your "since start" statistic to get a better idea of what your current fuel economy is.

Jorg

Because dealerships do not follow the break in rules with their demos that is why demos are not the very best deal you can get.

Good for you to stick to the recommendations for a short time only.

Jorg

delirium

Im curious how to vary the engine speeds... when on the highway, typically my engine speed is contstant...

Also 2/3 of the max engine speed means dont pass 5K RPMS?
is there a MPH limit during break in?

oblu

Actually, the way you guys are driving during break-in, the fuel economy is going to drop like a rock once it's over; once that magical 1k barrier is broken you'll all be stomping the gas like giddy 16yr olds.

MBTex

Generally you want to stay below 3K rpm's during the break in (on the 350 anyway according to the dealer). No real speed limit so long as the engine isn't being taxed. You very engine speeds by giving it an occassional acceleration to get the rpms up a bit. The point isn't to speed up the actual car, but to vary the rpms so the engine can be exposed to varying levels of work.

Modern engines usually don't need too much of a break-in, just be nice to it for the first 1000 miles or so and it'll be ready to go. I've left mine in Control mode since I got it and taken it easy, but I have really not held back too much because the car surprisingly seems to have more power then I would have anticipated for 270 hp. I'll still take it easy, but it hasn't been bad so far...only 800 more miles for me....taking two trips in the next two weeks to wrap up this "break in" period.

MBTex

Hell yeah I will....

If I cared about fuel economy I would've bought a hybrid accord...

JimPap

I was thinking about gettomg the Prius but couldn't figure out whether they were cute or ugly.

About fuel economy, at 1300 miles on my C300, I'm getting 26 mpg on the current tank of gas with my mixture of city and highway driving. I think I got 17 mpg on my first tank...which freaked me out.

ATSOBE

I have not reset mine since i bought it

715 mile
17.2 mpg
43:03 h
17mph

I drive it very a slow on c like the manual suggest not fast about 55 or 68 mph once or twice up 78 and one time at 700 mile i floored it try to move out of traffic. I do warm it up 5 or or 6 minutes everyday till i see the the tempature go up to middle. Maybe it eating my mpg cause the car is sitting making believe the trip computer it hardly moving. I sit alot in the car to warm it up everytime i start it. I am true believer in this keeps the car new. Why do i have poor gas milage i do someday alot expressway driving then other stop and go traffic. IM lost now with the gas milage after seeing all your high score in mpg. Mine only says 17.2

qwerty1024

This is just my opinion - I could well be wrong.
First hint would be the 17 Miles Per Hour speed average in the course of 715 Miles distance. That, to me, seems a very low speed average - I don't know what sort of traffic you're stuck in.

Second, the 5 to 6 minute warmp up is, in my opinion, absolutely unnnecessary. When doing the arithmetic to calculate all the averages for speed and fuel consuption and you factor in the time you're sitting still, these values will get skewed quite a bit. In 60-65* Faranheit I let the cold engine idle for no more than 30 seconds and then drive it using common sense: I don't rev-it to the stratosphere until normal operating temp is indicated.

And one other thing, it is still in the break-in period. It will get better MPG, but that will probably by offset by my spirited driving once the break-in is done.

Just my ideas - take it for whatever it's worth.

stephensong

Yesterday, roundtrip from Seattle to Portland plus drive around in Portland. Computer says " 433 miles, 8.13 hours, 27.1 mpg, 61 avg mph. This is outstanding. For those of you who don't know, the drive was down I-5 so most driving was freeway.

TomGator1

Sorry for not posting for awhile. I guess I should since I started this thread. Here's my latest update:

Since Reset:
2330 mi (# of miles since reset - I haven't reset it)
22.7 mpg (avg. mpg)
70:48h (total # of hours:minutes driven)
33 mph (avg mph)

Here's my first "Since Reset" post:
Since Reset:
770 mi (# of miles since reset - I haven't reset it)
21.5 mpg (avg. mpg)
27:24h (total # of hours:minutes driven)
28 mph (avg mph)

I have noticed my avg mpg ticking up by .1 every so often which indicates the car is getting better mpg as time goes on. I recently got 28.3 mpg on a 103 mile trip that included all types of traffic and highway speeds. I get better mpg when driving over 70 mph and when avg speed is over 45 mph. Anyone else noticing this?

cgarcia0638

Hmmm. All this talk about break in periods has me worried. I never paid any attention to the break in period in my 330i. Oh well, go figure.

RLE

<<I drive it very a slow on c like the manual suggest not fast about 55 or 68 mph once or twice up 78 and one time at 700 mile i floored it try to move out of traffic. I do warm it up 5 or or 6 minutes everyday till i see the the tempature go up to middle. Maybe it eating my mpg cause the car is sitting making believe the trip computer it hardly moving. I sit alot in the car to warm it up everytime i start it. I am true believer in this keeps the car new. Why do i have poor gas milage i do someday alot expressway driving then other stop and go traffic. IM lost now with the gas milage after seeing all your high score in mpg. Mine only says 17.2>>

And no wonder. It is not only not necessary to warm up the engine but is in fact harmful because the most engine wear occurs when the engine is below normal operating temperature. As someone else pointed out correctly, start it, and in the time it takes to belt up, the car is ready to go. Naturally, you wouldn't redline it right off the bat but just use common sense. The engine will reach operating temperature much more quickly than idling it. Particularly in Florida, for crying out loud.

tanktube67

how many miles your car has now and whats the mpg untill this day?

TomGator1

See my post from 12/2. I have 2330 miles total and 22.7 mpg. I have not reset the trip computer since I purchased the car.

Since Reset:
2330 mi (# of miles since reset - I haven't reset it)
22.7 mpg (avg. mpg)
70:48h (total # of hours:minutes driven)
33 mph (avg mph)

TomGator1

Should be interesting today. Will get to drive the C350 for the first time in the snow. I'll let you know how it handles.

JimPap

Is it really driving or more like snow boarding?

webada

Shouldn't be too bad, I drive a 528i in nyc now and before that a nissan 240sx in buffalo... all rear wheel drive.

I found that tire is the most important part during snow driving.... not necessary awd.

Then again, I've never driven a awd in snow. Anyone care to share their experience?