What is the real-world MPG of a Citroen C6?
Owners report an average of 34.6 mpg across all Citroen C6 engines with data, about 93% of the official combined figure. The engine tables on this page give the figure for each engine and generation.
Citroen C6 Real MPG: what owners actually get
The official figure is what a Citroen C6 managed in a laboratory. These are the figures owners report from the road, engine by engine, for every generation we hold. Add your own at the bottom and the averages get better for the next buyer.
34.6mpg
Real-world average, all engines
93%
of the official combined figure
27–44
Range reported by owners (mpg)
39
Owner submissions
Citroen C6
| Engine | Official (NEDC) | Official (WLTP) | Real MPG | % of official | Owners report |
|---|---|---|---|---|---|
| 2.2 HDi | 42.8 | – | 35.8 | 84% | – |
| 2.7 HDi V6 | 32.5 | – | 33.2 | 102% | 27.0–37.1 |
| 3.0 HDi V6 Automatic | 38.7 | – | 36.1 | 93% | – |
| 3.0i V6 | 25.2 | – | – | – | – |
All figures in miles per gallon (UK). “Owners report” is the spread of individual submissions for that engine.
Add your Citroen C6 Real MPG
What does yours actually do? Read it off the trip computer over a full tank or work it out from litres and miles. No postcode, no sign-up. The more people add, the better the averages get, and this page stays free.
Citroen C6 fuel economy questions
Why is the Citroen C6 real MPG lower than the official figure?
Official figures come from a laboratory test cycle, not the road. Cold starts, short trips, hills, load, tyres and driving style all cost fuel the test does not see. A gap of 10 to 30 per cent is normal; a much bigger gap on one engine usually points at a fault, a heavy right foot, or a diesel that never gets warm.
Where did the Honest John Citroen C6 Real MPG page go?
Honest John closed in August 2026 and its Real MPG section went with it. This page is where the Citroen C6 figures now live: rebuilt from the archived Honest John dataset, with the official figures kept alongside, and reopened for new submissions. CarAdCheck is not affiliated with Honest John or Volkswagen Financial Services.
Where the Citroen C6 figures come from
If you used the Honest John Real MPG section before the site closed in 2026, this is where the Citroen C6 figures now live. The owner-reported averages above were rebuilt from the archived Honest John dataset (archived page, 2025-12) alongside the official NEDC and WLTP figures and new submissions from CarAdCheck readers, and the section is open so they keep improving. Real-world figures also feed the running-cost estimate in our free advert check.
CarAdCheck is not affiliated with Honest John or Volkswagen Financial Services. How we rebuilt Real MPG.
Other Citroen models
Before you go and see it
Fuel economy is one line on the Citroen C6 running-cost sheet. These guides cover the checks that stop you buying the wrong one.
How to find a car's previous advertsThe most economical used cars in the real world, not the brochureThe Honest John alternative: how to research a used car for free
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