D5 (2005 on) Fuel consumption question

[JIM C]

My S60 D5 I get 42 mpg dong a 12 mile run to work in mixed traffic and middle to high 40`s on longer runs.

[RoyMacDonald]

I've said this before but diesels mpg gets better over the whole life of the engine. An accountant did a complete mpg check on his car (Citroen AX) from new to 200,000 miles and his car went from 40 mpg to 64 mpg. However it always fell by some 20 % in the winter because of the cold weather. The manufactures and Government never tell you this.

To sum up I think it's because your engine is new and the weather is cold and you are checking short journey runs.

You could check your brakes arn't binding to be on the safe side if you want. Chock the car and jack each wheel and make sure it spins freely.

Roy

[Alec Dawe]

My V70 D5 Geartronic with 24000 miles on it when I bought it in December was doing about 34mpg on mixed driving, gradually improving all the time. Got 42mpg out of her on Sunday to Ipswich and back (90 miles, country lanes, main road, and about 12 miles of dual carriageway), now getting round 38 in in mixed country lanes, bit of dual carriageway and in town driving.
A good booting up the dual carriageway resulted in a clear out (judging by the smoke!), and better running, and improved economy. No more smoke either, so what was there has gone away!
It may be that yours, being an ex-demo if I read the post right, has been pussy-footed with all its life, and might benefit from a bit of a thrash to blow the cobwebs out.
Mine seems happiest at about 76mph for cruising

[oilburner]

I drove my last diesel (not a D5 mind) from 17k to 50k miles and the average fuel economy picked up from 47 to 52mpg over that distance. Driving conditions and style remained the same.

Sometimes you just have to be patient and let the engine wear itself in a bit? Try giving it some welly (when warm) for a couple of weeks and see if that helps bed everything in a bit better.

I would expect with the distance you're driving and the regular regeneration of the DPF that you should get around 32-35mpg on a run in engine if you're reasonably careful with the loudness pedal! My Euro III with auto only manages 40mpg in near perfect long motorway/dual carriageway runs and very little urban driving at all.

[Clan]

Originally Posted by oilburner

I would expect with the distance you're driving and the regular regeneration of the DPF that you should get around 32-35mpg on a run in engine if you're reasonably careful with the loudness pedal! My Euro III with auto only manages 40mpg in near perfect long motorway/dual carriageway runs and very little urban driving at all.

With that figure and bearing in mind the fuel price differential , you'd be better off with a petrol

[petec]

hi i drive a d5 xc70 2005, distance to work 11 mile all stop start in traffic at the moment i am getting 36.6 mpg this increases to around 40 in the summer, car has now done 37k but dont remember fuel consumption ever being realy poor even with my twin axel caravan in tow i still get near the 30mpg mark.

keep an eye on your figures if your not happy try talking to your local dealer.
good luck

[oilburner]

Originally Posted by Clan

With that figure and bearing in mind the fuel price differential , you'd be better off with a petrol

I don't think I would (on local prices):

18k miles per year at 40mpg and 1.089p litre = £186pm

18k miles per year at 28mpg (2.4 auto petrol) and 1.059p litre = £258pm

For the OP poster I guess it would be more marginal however...I wonder what the 3.2 petrol would do in that driving? Anything less than 27mpg and the D5 will still save money!

The official combined is about 27 for the 3.2, if that was 10mpg worse for the original poster (like the D5) then they would only be getting 17mpg! Suddenly the D5 looks attractive again!

[Bernard333]

I have run a V70 D5 from new to 117k miles over four years and logged all fuel in a spread sheet , up to 10k miles the consumption gradually improved from 45mpg to an average of 55 mpg the lowest figures being in the mid 20s when doing 120mph plus on the autobahn and as high as 75mpg on 200 plus mile journeys Liverpool to Glasgow. The fuel economy is now definitely deteriorating since passing 110k miles down to an average of 50mpg and now difficult to acheive 60mpg on long runs which was quite easy earlier in its life . Mainly do calculations on a tank to tank basis but also a moving average over 5000 mile slots . Car is normally fully loaded either with 5 passengers or 500kG of load . If I cannnot continue to keep the mpg averaging over 50 then I will get rid , may consider another one as the running costs of my V70 have been very minimal and these are great workhorses. My company run quite a few Volvos and an economy minded colleague gets average 55mpg from his 2004 S80 D5 but this is on journeys like my own sometimes 500 miles plus in one day so the engine is hot most of the time . I would be interested to know from anyone what you can do to keep or improve the fuel consumption figures apart from the obvious driving techniques .

[Alec Dawe]

Improving your fuel consumptionafter 100K+? I think that there is a thread on the forum somewhere on cleaning out the air mixer box on the front of the engine. If full of crud, this seems to have a nasty effect on fuel consumption (reportedly) and cleaning it up is not a long nor terrible complicated job (after all, Mo did it!.... sorry Mo!).
Must be worth a look one Sunday morning when the weather warms up a bit?

[RoyMacDonald]

Originally Posted by Bernard333

I have run a V70 D5 from new to 117k miles over four years and logged all fuel in a spread sheet , up to 10k miles the consumption gradually improved from 45mpg to an average of 55 mpg the lowest figures being in the mid 20s when doing 120mph plus on the autobahn and as high as 75mpg on 200 plus mile journeys Liverpool to Glasgow. The fuel economy is now definitely deteriorating since passing 110k miles down to an average of 50mpg and now difficult to acheive 60mpg on long runs which was quite easy earlier in its life . Mainly do calculations on a tank to tank basis but also a moving average over 5000 mile slots . Car is normally fully loaded either with 5 passengers or 500kG of load . If I cannnot continue to keep the mpg averaging over 50 then I will get rid , may consider another one as the running costs of my V70 have been very minimal and these are great workhorses. My company run quite a few Volvos and an economy minded colleague gets average 55mpg from his 2004 S80 D5 but this is on journeys like my own sometimes 500 miles plus in one day so the engine is hot most of the time . I would be interested to know from anyone what you can do to keep or improve the fuel consumption figures apart from the obvious driving techniques .

Bernard, your mpg should not be falling so I suspect that there is something causing it. The mpg on my 940 TD fell at around 120,000 and it took a diesel specialist to find and cure it after which it was better than ever and still improving when I sold it at 165,000. I won't bother to go into details as it's a very different engine and electronic setup to the D5.

Diesel Car mag published the records of an accountant who kept his car for 200,000 miles from new, recording the mpg for every tank of fuel it used. This showed an increase for the whole life of the vehicle from new. It went from 46 to 64 mpg.

Has the air mixer box ever been cleaned? Having seen the state of members engines posted here that would be good culprit to start with. Run a search on Air Mixer Box to see what I mean. Check the brakes aren't binding at all of course, make sure the wheels all spin freely. Even slight drag will cane the fuel consumtion. Then maybe take a look at the head and injectors if all else fails. I feel sure you will find a fault at some point. Diesel engines should carry on giving good fuel consumption for many years if they are properly looked after.

Roy