December 29, 2011, 1:10 pm
First of all Jonh welcome to the forum. Secondly, I am going to assume you have a DPF for the advice below...
Diesels are much better for long journeys, as during short journeys they take longer to warm up, dont heat up the DPF enough, and as such can get clogged up and cause some cack to build up inside the system. to improve MPG review the following as a start:
1) When was the last time the following were replaced?
[*]DPF (If done)
If any of the first three have not been done in the last 2 years, consider them as a possible contribution.
I suspect you may have the DPF on this model, and as such the mileage will impact on it. How was the car driven before you purchased it? same sort of daily commutes? what is the mileage of the car? if about 37500 then the Eolys fluid will need replacing if not done, and the DPF will need replacing if it has passed 70000 miles.
2) What grade of fuel are you using? supermarket or otherwise?
3) have you tried any additives? the likes of BG244 are very good at removing carbon deposits and clearing the engine block to allow a more efficient combustion process.
4) Consider something such as "Whynns EGR Cleaner" as if the EGR is cacked up then that might help also
5) Take the car for a motorway run, keep the speed at a 'legal' place on the speedo, but keep the revs high (above 3500 would be good) and maintain that rev range for a moderate amount of time (a good run at this engine speed for 15-30 minutes will help). This will get the exhaust gasses up to a high temperature, and will do a "passive regeneration" on the DPF. This will clear it out, reducing back pressure, and making the engine work easier and more efficiently.
That is a good place to start