Terrible gas mileage on C300 6 speed?
Thread Starter
Newbie
Joined: Nov 2008
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08 C300
Terrible gas mileage on C300 6 speed?
Hey everyone,
New to the forum, joined to get some information for my cousin. He owns a 2008 C300 sport with the 6 speed transmission. It's a really nice car, he's got most of the options: 18" AMG rims, rear spoilers, premium package 2, etc. Anyway, recently he's been paying more attention to his MPG, and have been noticing that it's been awful. Last time he filled I believe he averaged 13.2 mpg, which has been the lowest. I believe the past two fill ups was around 14-15.
He really babies the car, never floors it/redlines it, race it, etc. He always uses premium 91+ gas. We are just kinda of baffled as to why he would get such bad gas mileage? He got the car brand new last January. It has about 3-4k miles on it. He drives almost 100% city, daily commute is maybe 1-2 miles if that. At first I was thinking maybe it was the bigger and wider tires/rims, or even thinking maybe it's not broken in all the way yet, but 13 mpg is pretty awful. I even checked his tire pressure prior to the fillup and topped them off to correct amount.
Just curious if anyone has any ideas as to whats going on. I'd rather ask people on forums before he goes to the dealership and gets jerked around.
Thanks!
New to the forum, joined to get some information for my cousin. He owns a 2008 C300 sport with the 6 speed transmission. It's a really nice car, he's got most of the options: 18" AMG rims, rear spoilers, premium package 2, etc. Anyway, recently he's been paying more attention to his MPG, and have been noticing that it's been awful. Last time he filled I believe he averaged 13.2 mpg, which has been the lowest. I believe the past two fill ups was around 14-15.
He really babies the car, never floors it/redlines it, race it, etc. He always uses premium 91+ gas. We are just kinda of baffled as to why he would get such bad gas mileage? He got the car brand new last January. It has about 3-4k miles on it. He drives almost 100% city, daily commute is maybe 1-2 miles if that. At first I was thinking maybe it was the bigger and wider tires/rims, or even thinking maybe it's not broken in all the way yet, but 13 mpg is pretty awful. I even checked his tire pressure prior to the fillup and topped them off to correct amount.
Just curious if anyone has any ideas as to whats going on. I'd rather ask people on forums before he goes to the dealership and gets jerked around.
Thanks!
Super Member
Joined: Dec 2007
Posts: 648
Likes: 1
From: Seattle
C-300, XC70, Wrangler
Take a trip. Go somewhere where the car has to be driven at 65-75 for a few hours, then check the mileage. If it's still bad, then maybe the car has a problem. If the mileage hits or exceeds 27, then the problem is how he's driving on those city streets.
I'm driving the 7-spd, and I've seen 13 on a single day's city driving. Lots of stop signs, red lights, and such. Then I took the car on the road and hit 32. So some city driving can be bad. Mostly my city driving is at about 21 or so, but ...
These cars drink gas on start-off from a stand-still. They drink gas on the on-ramp. It takes blocks and blocks to get it back on streets, and up to 3 miles to get it back on the freeway. ("Get it back" here is defined as to recover the mpg reading you had before you tromped the loud pedal.)
I'm driving the 7-spd, and I've seen 13 on a single day's city driving. Lots of stop signs, red lights, and such. Then I took the car on the road and hit 32. So some city driving can be bad. Mostly my city driving is at about 21 or so, but ...
These cars drink gas on start-off from a stand-still. They drink gas on the on-ramp. It takes blocks and blocks to get it back on streets, and up to 3 miles to get it back on the freeway. ("Get it back" here is defined as to recover the mpg reading you had before you tromped the loud pedal.)
Thread Starter
Newbie
Joined: Nov 2008
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08 C300
jstaneff: I was actually planning on doing that with him. Fill it up then jump on a highway and keep it at 65mph in 6th gear with cruise on for a good amount of time, then fill up again to see what kind of mpg he's getting.
Super Member
Joined: Nov 2007
Posts: 923
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From: North Jerzeee
Lexus IS 350 F Sport
At what mileage is the car considered 'fully broken in'?
jstaneff: I was actually planning on doing that with him. Fill it up then jump on a highway and keep it at 65mph in 6th gear with cruise on for a good amount of time, then fill up again to see what kind of mpg he's getting.
jstaneff: I was actually planning on doing that with him. Fill it up then jump on a highway and keep it at 65mph in 6th gear with cruise on for a good amount of time, then fill up again to see what kind of mpg he's getting.
regular city driving with lots of stop and go id be lucky to go anywhere near the high teens 
ps i've got the 4matic with auto
Super Member
Joined: Jul 2002
Posts: 678
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From: Vancouver WA
'14 GLK250 Diesel
This is easy - look at the original question!
The car never gets warmed up....no wonder the fuel consumption is crappy. In strictly city usage, ours never gets better than 15 mpg....in our case, that is practically never, as ours spends most of its time on the freeway with the coolant and oil fully warmed up.
The suggestion to take the car out for a good airing once in awhile is a very good idea.
A gasoline V6 C is NOT an economical city car.....period. Your fuel consumption is precisely what I would expect it to be under the circumstances described.
The car never gets warmed up....no wonder the fuel consumption is crappy. In strictly city usage, ours never gets better than 15 mpg....in our case, that is practically never, as ours spends most of its time on the freeway with the coolant and oil fully warmed up.
The suggestion to take the car out for a good airing once in awhile is a very good idea.
A gasoline V6 C is NOT an economical city car.....period. Your fuel consumption is precisely what I would expect it to be under the circumstances described.
MBWorld Fanatic!
Joined: Dec 2002
Posts: 1,398
Likes: 7
Indeed, and the car is heavy, moving that mass from a dead stop is the main factor keeping MPG down.
So far, after 8 weeks ownership, I'm OK with the mpg on my 3004M. I'm getting just under 26 in 80/20 highway/city driving. One night last week on a particularly smooth trip home from work, at the end of the highway portion of my commute, the trip computer showed 28.1 mpg for that segment, that's the best I've done so far.
So far, after 8 weeks ownership, I'm OK with the mpg on my 3004M. I'm getting just under 26 in 80/20 highway/city driving. One night last week on a particularly smooth trip home from work, at the end of the highway portion of my commute, the trip computer showed 28.1 mpg for that segment, that's the best I've done so far.
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MBWorld Fanatic!
Joined: Oct 2008
Posts: 2,601
Likes: 28
From: Atlanta, GA
2008 C300 Sport 6 Speed Manual, 1953 Chevy Bel-Air, 2015 Audi allroad, 1963 Chevy Apache
I do about 90% city driving with most trips under 5 miles. I have a good bit of stop and go and have been averaging about 19 mpg. Mine just got broken in (1600 miles in 3 months) but I really don't expect to do much better with a 3500lb car in the city. On my three road trips(between 80 and 120 miles each) I hit the upper twentys, with one trip hitting 31 as I was coming up the offramp.
13-14mpg sounds like a mechanical problem to me unless you are really sitting a lot in those short trips to the office. Take a cab the mile to work and get the car out on the highway...
13-14mpg sounds like a mechanical problem to me unless you are really sitting a lot in those short trips to the office. Take a cab the mile to work and get the car out on the highway...
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Almost a Member!
Joined: Sep 2008
Posts: 61
Likes: 0
From: Germany
C300 Sport
I do about 90% city driving with most trips under 5 miles. I have a good bit of stop and go and have been averaging about 19 mpg. Mine just got broken in (1600 miles in 3 months) but I really don't expect to do much better with a 3500lb car in the city. On my three road trips(between 80 and 120 miles each) I hit the upper twentys, with one trip hitting 31 as I was coming up the offramp.
13-14mpg sounds like a mechanical problem to me unless you are really sitting a lot in those short trips to the office. Take a cab the mile to work and get the car out on the highway...
13-14mpg sounds like a mechanical problem to me unless you are really sitting a lot in those short trips to the office. Take a cab the mile to work and get the car out on the highway...
Shawn
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Joined: Mar 2007
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This thread is relevant, some might find it interesting: https://mbworld.org/forums/c-class-w...ngine-rpm.html
Out Of Control!!
Joined: Sep 2005
Posts: 18,414
Likes: 6
From: West Michigan
2007 E63
This is easy - look at the original question!
The car never gets warmed up....no wonder the fuel consumption is crappy. In strictly city usage, ours never gets better than 15 mpg....in our case, that is practically never, as ours spends most of its time on the freeway with the coolant and oil fully warmed up.
The suggestion to take the car out for a good airing once in awhile is a very good idea.
A gasoline V6 C is NOT an economical city car.....period. Your fuel consumption is precisely what I would expect it to be under the circumstances described.
The car never gets warmed up....no wonder the fuel consumption is crappy. In strictly city usage, ours never gets better than 15 mpg....in our case, that is practically never, as ours spends most of its time on the freeway with the coolant and oil fully warmed up.
The suggestion to take the car out for a good airing once in awhile is a very good idea.
A gasoline V6 C is NOT an economical city car.....period. Your fuel consumption is precisely what I would expect it to be under the circumstances described.
Member
Joined: Nov 2007
Posts: 244
Likes: 2
From: Texas
2014 E350 Coupe Steel Gray
+1 to this whole post. I get roughly 21-23 mpg consistently and I drive about 40 miles RT to work/home in sometimes stop and go traffic. I get much better on the highway.
