[90MSP]

So I have recently replaced by thermostats on my 2006 330D M Sport. After doing this the car runs at 90 degrees and above as it should, however no matter how I drive (light footed long careful motorway journey) I struggle to get the OBC to maintain a reading of 40 mpg. Off the motorway this will drop to mid thirties.

What do you guys get ?... does that sound about what I should expect ?.

[330ray]

Id say thats poor to be fair i get a tiny bit less then that from my 330i

[CustomColours]

Straight 6 diesels arent going to pull amazing mpg imo although I could be right. People I know have got little diesel run around cars with 1.6tdi engines and they are only just seeing low 40's in town driving and low 50's motorway. Those cars wiegh allot less and have less poke so pursonally I would see that as normal. My 535d was only getting high 20's around town. Motorway im not sure as I dont often use them.

[jammy78]

I'm only getting 36-38mpg from my 330D (245bhp) & my temps are fine!

[Cero ceto]

We'll I'm getting 47 MPG on a good run in my 330d (245). I was getting 62 in my old golf TDI (140), but I cannot complain as the 330d is a great compromise between power and economy in my opinion.

[CustomColours]

Just as I was saying. Your driving a reasonably powerful 6 cycle diesel bolted in a car thats not the lightest around. Its never giving you these dreamt up 60+mpg I hear people waffle about.

Its not that bad on fuel and it has poke. You cant ask for more.

Remeber to cater in the cost of deisel compared to petrol though and you start to realise that unless your doing ling trios. Diesels arent a huge jumo better than its apposing petrol.

[AzRiz]

On my 50-mile commute to work, with average flowing traffic, I regularly get 50+ MPG in my 330d 245bhp when cruise is set to 60mph for the motorway stretch. This journey is 80% motorway, 10% A-roads and 10% town driving.
When cruising at 70ish on the motorway stretch, I struggle to hit 47mpg on the same journey.

EDIT: These are the figures on the OBC, not calculated manually

[90MSP]

As I have only had the car 3 weeks or so, not sure how long the thermos have been shot for. So now wondering what damage may have been caused and if could affect my mpg, clogged EGR etc

[E92Dan]

I get 40mpg out of my 330d, that compares to 27mpg from my old mk5 Golf GTI 2.0turbo and BMW Z4 3.0 petrol.
Diesel is 5p per litre more than petrol where I live, that is only a couple of percent more so not worth worrying about

[Dsport]

I get 36/37 50% motorway and rest is traffic, also not sure if mine is a 231 or a 245

[CustomColours]

I consider anything over 35mpg in a 330d brilliant. Driving style does help aswell.

[oldbilly]

what about changing the egr thermostat, about £30 and diy takes about 15 minutes!

[jquan1]

Originally Posted by CustomColours

I consider anything over 35mpg in a 330d brilliant. Driving style does help aswell.

Have you ever owned a 330d?

I have had mine for nearly 3 years now and cannot however hard I try get it to read below 34mpg. It's usually 41mpg, which is a mixture of town and dual carridgeway. I've had it up to 52mpg on a long motorway journey.

Compared to a petrol it is far, far better mpg wise. A few pence on a litre extra of diesel makes no noticeable difference.

[jammy78]

I've just drove 125 miles, no traffic - cruising & I averaged 79mph (remember BMW speedo is about 5mph above)..... I got 40.8mpg

[Bfc1882]

I would say you are bang on with that. If you get anywhere above 35mpg you are doing well. If you want 40mpg buy a 116d. I have a 330d auto with new thermos and 35 with a mixture of driving is your lot.

[SO8]

35-48 in my 330d lci auto.

I have seen 61mpg over a 75 mile motorway trip at 55mph for the length of the M3 but that wasn't what I call normal driving ! It is currently showing 36mpg for commuting in light traffic 10 miles each way to work in Surrey.

[E92Dan]

Originally Posted by jammy78

I've just drove 125 miles, no traffic - cruising & I averaged 79mph (remember BMW speedo is about 5mph above)..... I got 40.8mpg

My Speedo is only out by 2mph. My 40odd mpg is lots of high speed motorway and A+B roads

[NotNormal]

OP - have you / do you check you actual mpg by filling up the tank to the brim and using it, then brimming it again - working out the mpg by the exact fuel used ?
Or are you going by your on board computer ?

My 335d use to average 34mpg over the 100,000 miles I had it for - mixed driving, I have a very very heavy right foot
The obc used to read all over the shop, from low 29's to late 40's .....

(I ran a DTUK tuning box, swirl flap delete and EGR delete)

[Icekube]

i wouldnt be trusting the OBC to give you the correct MPG, the only way to do it is by working it out yourself by brimming the tank every time, and taking the mileage, every time.

you can use www.fuelly.com to keep track of everything for you

[Dan-danGT]

I have a e90 pre lci 330d auto with new thermostats. Dpf removed and remapped it made 269hp and about 440 ft ibs of torque. Well on a trip to the nurburgring this year I'm in the midlands and I managed to average around 42mpg calculated. Obc is pretty close to what I calculate I don't drive like a old man at 60mph! I will do 70 minimum on a motorway. I also did a trip to cumbria just two weeks ago and I got 42mpg again.

However around town I get 28-32mpg if that. But for the performance I can't knock it at all, if economy is what yours after buy a poverty model 116d or 318d! I always expected mine to be better but it's just how it is.

If you think that's low after one lap of nurburing I managed a indicated 12mpg and a lap is about 12 miles now that's low!

[E92Dan]

I've found my OBC to be very accurate. I do manual checks every fourth fill and it's never out by more than 1mpg.

[90MSP]

Wil give my EGR a clean up this weekend to see if that improves things a little bit. I also add Millers EcoMax to each tank, that takes a few tanks full to come into effect but when it does it's good. I added it to an Alfa I had and the engine 'smoothed out' nicely after a few tanks, plus added a couple of mpg and a bit more oomph.