CLK270 Fuel Consumption; What to expect?

[Pauleo09]

I've had a CLK270 for a few months now and the fuel consumption hasn't been great. The on-board computer indicates I'm doing between 35>40mpg on average over a combination of town driving and straight runs.
All the tyres are good, levels are fine, 8000+ before next service, not driven with a heavy foot, but I'm getting about 350 miles on a full tank. Is that right? Is there anything I can do to improve it?

I'll probably look to throw some engine cleaner in (e.g. redex) to see if that helps at all but due to this, I've been wonder whether to go down the road of re-mapping, but I've heard mixed opinions.

Any suggestions or thoughts are very welcome!!

Thanks everyone!

 

[Carrsey]

I use to have a CLK270 and from what I remember high 30s was about right for mixed driving.

Remember the older diesels are nowhere as economical as the newer ones..

 

[Carrsey]

Think the official figures are 40. So knock a couple off to be realistic = 38.

 

[clk270]

I ran one from new back in 2003 for 5 months and ca 4500 miles. At the time I had a short 5 mile commmute, lightly traffic'd in the mornings but more queueing in the eveings. I used to get 40mpg on the commute, rising to high 40s t the weekend with steady 10 mile shopping trips. Overall, I came out around 43mpg (Avantgarde spec, with 17" wheels) over the whole ownership period, even with using the manual override on the auto box from time to time

I'd recommend Millers EcoMax as a fuel cleaner/additive - its ca £11 a bottle on eBay, but a bottle will last 15 tanks; its both a cleaner and additive (its increases cetane rating slightly) and I've found it very effective in a variety of both used and new diesels.

PS - I dare say you've already done so, but check tyre pressures with a proper gauge, regularly (esp[ecially now as ambient temperatures are dropping in the approach to winter) - 2 or 3 psi can make a few mpg difference.

 

[DSM10000]

Also, check that the engine is reaching the correct temperature, should be around 90Deg C. Thermostat failures is not uncommon and will not help with fuel consumption figures.