Having filled-up a few times since the service we covered in our previous report, we’ve noticed something that may just prove a theory I’ve held for some time: that modern diesels don’t produce decent mpg figures until they’ve completed at least 10,000 miles and have ‘loosened up’.

In the case of our Legacy diesel, the car’s jumped from doing 40-42mpg on my commute (mainly M25) before the service to now returning 48-50mpg, and with little eco-driving effort I’ve seen the trip computer read more than 51mpg.

We’ll keep an eye on the situation to see if it continues.

Subaru Legacy Sport Tourer 2.0D RE
Mileage 13,621
Claimed combined consumption 48.7mpg
Our average consumption 38.7mpg
P11D price £22,795
Model price range £18,995-£30,705
CO2 (tax) 154g/km (21%)
BIK 20/40% per month £79/£159
Service interval 12,000mls
Insurance group 13
Warranty 3yrs/60,000mls
Boot space (min/max) 459/1628 litres
Engine size/power 1998cc/150PS
Top speed/0-62mph 126mph/8.5secs
Why we’re running it To test Subaru’s first
ever diesel engine
Positive Engine refinement,
practicality
Negative Powered mirrors
don’t auto fold