Poor mpg

[steve333]

Just used the 1st tank in the wife's slk200k(2009) and was shocked to see the car had only averaged 22mpg(brim to brim,obd showed 23.7 mpg).Car had a b service,ATF/filter change,plugs,brake fluid,air filter,pollen filter,coolant,tyre pressures checked and ok,tyres new all round and tracking ok,air con on all the time,driven in comfort mode mainly urban driving(not sitting in heavy traffic, although some short journeys).Car drives normally,no messages or elm,kickdown works fine any ideas before I get the car booked in and checked on star?

 

[John]

Not got a lot of experience with 200K engines but I drove a C200K estate for a while and it was about that on fuel (W reg though I think) - really shocked as that is about the same as mine nearly!

I would have said that sounds about right for urban driving with a slushy auto (I guess 7g in it?) on that sort of car.

 

[steve333]

Not got a lot of experience with 200K engines but I drove a C200K estate for a while and it was about that on fuel (W reg though I think) - really shocked as that is about the same as mine nearly!

I would have said that sounds about right for urban driving with a slushy auto (I guess 7g in it?) on that sort of car.

Hi John,it's a 5 speed auto which is probably less economical than the later 7 speed models,identical journeys over a tank in her previous 2003 slk230k with a 5 speed auto use to average 26.5 mpg.

 

[zipdip]

Well that is well low,with the sort of driving you have been doing I would expect 30 mpg at least,something wrong

 

[John]

Yes, the 5g is not as efficient as the 7g although how much difference it makes in the real world...

I think the E500 running 7g does a combined 25.6 or something and the 5g one is 23.something - it's that close anyway.

I'm not saying there isn't an issue - I'd still consider getting it checked (after all, I don't know whether there was a problem with the C200 I drove) - you'd think it would be closer to 30mpg with that sort of engine, a kompressor and not-too-heavy-right-foot.

 

[steve333]

Well that is well low,with the sort of driving you have been doing I would expect 30 mpg at least,something wrong

That's what I thought,will monitor next tank average mpg but I average 25 mpg in my A45Amg!

 

[steve333]

Yes, the 5g is not as efficient as the 7g although how much difference it makes in the real world...

I think the E500 running 7g does a combined 25.6 or something and the 5g one is 23.something - it's that close anyway.

I'm not saying there isn't an issue - I'd still consider getting it checked (after all, I don't know whether there was a problem with the C200 I drove) - you'd think it would be closer to 30mpg with that sort of engine, a kompressor and not-too-heavy-right-foot.

That's my thoughts-mrs definitely doesn't have a heavy right foot either!

 

[geraldrobins]

That's what I thought,will monitor next tank average mpg but I average 25 mpg in my A45Amg![/QUOT

I think you will find the official mpg figures and emissions are better on your A45 than a R171.

 

[KennyN]

What is your average speed over a full tank , i manage around 20mpg in my CLS during my daily commute which averages around 15 mph . If my average speed increases to around 20 the the MPG increases by around 25%.

Kenny

 

[steve333]

That's what I thought,will monitor next tank average mpg but I average 25 mpg in my A45Amg![/QUOT

I think you will find the official mpg figures and emissions are better on your A45 than a R171.

They are on paper but I don't drive the A45 like the mrs drives her slk

 

[steve333]

What is your average speed over a full tank , i manage around 20mpg in my CLS during my daily commute which averages around 15 mph . If my average speed increases to around 20 the the consumption increases by around 25%.

Kenny

Not sure what the average speed was but will check on next refill.

 

[geraldrobins]

They are on paper but I don't drive the A45 like the mrs drives her slk

Lots of factors to consider of course. Lots of the time you can only drive as fsat as conditions and traffic allow. Also does your wife do similar journeys as on short journeys the ave mpg will be low as the car hasn't or only just warms up.
Lets hope it improves.

 

[Scooby_Doo]

I had a manual SLK200 back in 2001 and average mpg was 30+ regularly,daily commute was about 16 miles each way.

 

[leef44]

It must be a dud. You've actually got yourself a SLK 55 AMG disguised as a SLK 200.