Parkers overall rating: 4.1 out of 5 4.1

Miles per pound (mpp) Miles per pound (mpp)

Petrol engines 6.3 - 7.7 mpp
Diesel engines 7.6 - 9.2 mpp
Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Fuel economy

Petrol engines 29.7 - 36.2 mpg
Diesel engines 37.7 - 45.6 mpg
  • Mercedes-Benz CLS tested on new economy standard
  • Mpg figures less impressive but slightly more realistic
  • Both diesel engines offer good economy, petrol less so

The new CLS is the first Mercedes-Benz to undergo the WLTP emissions test, which is tougher than the previous incarnation, though figures are currently backwards-calculated to be broadly comparable to the previous test.

As such, the economy figures look slightly less impressive than other models from the German manufacturer, but should be a little closer to what you’ll actually achieve.

Currently the best mode for low running costs, unsurprisingly, is the lowest-powered diesel, the CLS 350 d 4Matic, which boasts 48.7mpg when driven carefully.

The more potent CLS 400 d 4Matic uses the same basic engine and as such offers a broadly similar 47.9mpg despite packing a more sizeable punch.

Worst off is the CLS d 450 4Matic with a claimed 36.2mpg – still a reasonable figure considering the size and performance of this sporty coupe.

The CLS 350 d and 400 d 4Matics offer the same 156g/km of CO2, while the CLS 450 4Matic claims a comparatively less impressive 184g/km.

Still, Mercedes-Benz says this model features a similar amount of power as the previous V8 CLS 500, while putting out 23% less CO2, so that’s quite clever.

  • Lots of shared tech with E-Class
  • New engines are a bit of an unknown
  • Should be a fairly solid car though 

Given that the Mercedes-Benz is based on the E-Class’s architecture we’d suggest its components should be reasonably well tried and tested.

However, all of the engines are new and in Mercedes’ own words, very sophisticated, so time will tell how those fare.

As a manufacturer Mercedes-Benz has historically been a bit patchy in terms of reliability but its latest generation of cars certainly seem to be moving the game on.

Ongoing running costs

Road tax (12 months) £475
Insurance group 47 - 50
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