435d mpg and coolant temps - is this right?

[chrisski.x]

Hi all,

I have recently been watching the coolant temps on my 435d because I don't think driving the car in eco-mode as carefully as possible should be returning only 35mpg absolute tops, even on a long drive in good traffic conditions (in comfort driving normally I'll manage 32mpg). Last night I made a note of the temps as the time and miles went by and I'm sure my car is not reaching the correct temps - can anyone let me know if this sounds normal or whether a stat is likely faulty?

Outside temp was 3deg. First part of the journey was in a town creeping along at 5mph, then stopped to fill up, then 40mph for a while, then 60mph for most of last part.

5 mins / 0 miles - 47 deg - town, slow
7 mins / 0 miles - 50 deg - stopped for fuel
9 mins / 1 mile - 55 deg - town, slow
11 mins / 1 mile - 57 deg - town, slow
14 mins / 2 miles - 73 deg - urban @ 40mph
18 mins / 5 miles - 80 deg - urban @ 40mph
19 mins / 6 miles - 86 deg - urban @ 40mph
20 mins / 7 miles - 86 deg - urban @ 40mph
21 mins / 7 miles - 88 deg - urban @ 40mph
21 mins / 7 miles - 86 deg - urban @ 40mph
21 mins / 8 miles - 88 deg - urban @ 40mph
21 mins / 8 miles - 87 deg - urban @ 60mph
22 mins / 8 miles - 86 deg - urban @ 60mph
22 mins / 9 miles - 86 deg - urban @ 60mph
23 mins / 9 miles - 87 deg - urban @ 60mph
24 mins / 9 miles - 85 deg - urban @ 60mph
24 mins / 9 miles - 88 deg - urban @ 60mph
25 mins / 10 miles - 86 deg - urban @ 60mph
25 mins / 10 miles - 87 deg - urban @ 60mph
26 mins / 11 miles - 89 deg - urban @ 60mph
27 mins / 11 miles - 87 deg - village @ 30mph
28 mins / 12 miles - 86deg - home, engine off.
29 mins / 12 miles - 90 deg - engine off.

First of all, does this look like a normal warm up speed and secondly, I think more importantly, is 86~89 the correct operating temperature or is this too low - and if so is the car therefore always over-fueling?

I have 8 months on warranty but I am reluctant to take it to BMW only to have them tell me there's nothing wrong (for which I guess I will be charged for) until I am certain there is a problem!

[Huskyman]

If the temps stayed down around 70 degrees then I would worry. 35mpg for extra urban souds normal to me, take it for an extended drive at normal motorway speeds for longer than 30minutes, it will give the DPF a chance to regenerate.

[p1stonhead]

chrisski.x said:

Hi all,

I have recently been watching the coolant temps on my 435d because I don't think driving the car in eco-mode as carefully as possible should be returning only 35mpg absolute tops, even on a long drive in good traffic conditions (in comfort driving normally I'll manage 32mpg). Last night I made a note of the temps as the time and miles went by and I'm sure my car is not reaching the correct temps - can anyone let me know if this sounds normal or whether a stat is likely faulty?

Outside temp was 3deg. First part of the journey was in a town creeping along at 5mph, then stopped to fill up, then 40mph for a while, then 60mph for most of last part.

5 mins / 0 miles - 47 deg - town, slow
7 mins / 0 miles - 50 deg - stopped for fuel
9 mins / 1 mile - 55 deg - town, slow
11 mins / 1 mile - 57 deg - town, slow
14 mins / 2 miles - 73 deg - urban @ 40mph
18 mins / 5 miles - 80 deg - urban @ 40mph
19 mins / 6 miles - 86 deg - urban @ 40mph
20 mins / 7 miles - 86 deg - urban @ 40mph
21 mins / 7 miles - 88 deg - urban @ 40mph
21 mins / 7 miles - 86 deg - urban @ 40mph
21 mins / 8 miles - 88 deg - urban @ 40mph
21 mins / 8 miles - 87 deg - urban @ 60mph
22 mins / 8 miles - 86 deg - urban @ 60mph
22 mins / 9 miles - 86 deg - urban @ 60mph
23 mins / 9 miles - 87 deg - urban @ 60mph
24 mins / 9 miles - 85 deg - urban @ 60mph
24 mins / 9 miles - 88 deg - urban @ 60mph
25 mins / 10 miles - 86 deg - urban @ 60mph
25 mins / 10 miles - 87 deg - urban @ 60mph
26 mins / 11 miles - 89 deg - urban @ 60mph
27 mins / 11 miles - 87 deg - village @ 30mph
28 mins / 12 miles - 86deg - home, engine off.
29 mins / 12 miles - 90 deg - engine off.

First of all, does this look like a normal warm up speed and secondly, I think more importantly, is 86~89 the correct operating temperature or is this too low - and if so is the car therefore always over-fueling?

I have 8 months on warranty but I am reluctant to take it to BMW only to have them tell me there's nothing wrong (for which I guess I will be charged for) until I am certain there is a problem!

Id say the first 14 minutes doing 2 miles was so bad on MPG that it only averaged out to 35mpg by the end of the other 15 minutes and 10 miles.

Is it really that bad on a long say 60mph cruise on a motorway? Anecdotal stories online suggest it should be at least mid 40s.

[helix402]

Coolant temps are correct.

[Ken Figenus]

Just about get 50mpg from my F11 535d if i'm a really good boy on the motorway - 75mph on cruise in eco pro. A pacey A road drive is about 38. Car long term sits on 35mpg with a mix of town and short journeys etc.

Had an E61 and worried about the stats (so changed them) and your figures look fine...

[chrisski.x]

Thanks for your reply Huskyman So that 86~89 range is normal operating temperature and the 18 minutes to get there is also normal for this car / engine?

Since posting this I did find a thread on another forum saying they were seeing the same range but before then I read a post stating 89 to 91 is normal for this car and therefore I wondered whether my car always thinks it is under temp. Whilst monitoring I've never seen it hit 91 and I've done that on quite a few different drives recently including a nice 1.5 hour blast on a semi-decent day (for this year so far at least!) with varying a-roads and b-roads and also on a hour long motorway set on cruise @ 70mph. No matter what, though, the mpg is always between 32 and 35 in a car others state they regularly see 40+.
And I can assure you I have driven it extremely economically to find just how much I can squeeze out of it! It's weird, it actually becomes a challenge where you end up getting really annoyed with other people on the road making you brake when you didn't need to... this despite the real reason for buying the car was foremost the power.

Edited by chrisski.x on Tuesday 20th March 17:13

[chrisski.x]

Ken Figenus - see, I would have thought the 435d (I have F36) would be slightly better than a 535d if for weight alone but I honestly can't see how on earth I'd ever see a 50mpg average on any drive unless I reset the trip computer after I am cruising at 70mph...


helix402 - thank you, that's reassuring even if I would like to have found fault. Would have been nice to have something to blame the mpg on. Are those warm up times normal?


p1stonhead - last long trip I did was just over an hour, mostly motorway, returned 35mpg

[stevesingo]

xDrive?

[Ken Figenus]

I rarely touch the brakes on mine when on an mpg crusade - especially if I've just cleaned the wheels So if you are driving in that 'anticipate - dont brake' way too when you are trying to win the high mpg game you really should be getting mid to high 40's min on flowing road or a motorway at 75. Stats sound OK mate so I'd look elsewhere - EGR maybe?

Isn't it completely barmy to get 50mpg on a car that's 330bhp and almost 500LbFt - its a brilliant engine but I so dislike that car as the EPAS is truly imprecise and awful and I had to ditch the runflats first week on a brand new car and it still hops and jumps on 19" wheels. BMW have lost the plot with road manners/plantedness - everything else comes before dynamics and surefootedness. Truly awful decisions made - far preferred my HPAS E61 on 18" non RFT.

[Wills2]

I don't see the issue with getting 30mpg from a 3.0l 6 with 300hp on the urban cycle.

[Pica-Pica]

My 335d xdrive, takes about 10 miles to get to operating temperature of 100. Which is usually my minimal journey length. I get a consistent 44-45 mph, measured over at least three tank fulls. That matches the computer mpgs given. I drive moderately - can’t do much else in modern traffic - with the occasional blast for an overtake or fun drive. I am surprised when people get below 40mpg, and amazed when people get over 50mpg. I have had good intentions and often begin a long drive in the inside lane of an Mway, with the intention of seeing what mpg I can achieve, but then I get bored and move it along a bit.

For reference, I almost always use Shell, mostly V-Power. She’ll fuel stations are frequent near me and reasonably priced and open late, so that is why.

[Mr Whippy]

I’ve noticed long warm up in winter impacts short ish journey mpg.

Also expect 10k miles to bed the engine in nicely.

Lastly, it’s a big heavy car with awd. Constant speed is what gets you good mpg.

[Gary Kinghorn]

Mine does 30mpg on my very short drive to work and knocking around town picking the kids up etc and that's taking it very easy. If it's cold it might drop to 28 or 29. To get that figure back to something like 35mpg I need to take it on a run of 7 or 8 miles.

Taking it on a decent journey it does just over 40mpg, but that needs to be something like 15 miles or more.

On a long motorway journey I might see something like 43 or 44mpg. I don't hang around, but nor do I drive like a mad man.

I couldn't get 50mpg out of mine if I tried ....... without tailgating lorries etc and driving very very steadily.

F36 435d 2017

All mpg figures are indicated, not tank to tank verified.

[chrisski.x]

More and more it feels like it's luck of the draw whether you have a '35d engine capable of high mpg figures... at least they're all consistent in high bhp & torque figures.

Think I'll look into the EGR still. Anyone know what BMW will do if I take to them on a warranty claim to look at it??

[Welshbeef]

Wills2 said:

I don't see the issue with getting 30mpg from a 3.0l 6 with 300hp on the urban cycle.

You should if the heavier F10 535d without Eco pro does mid 40’s all day long.

[Gary Kinghorn]

I would imagine it will depend entirely on the sort of driving you do. If you go out of your door, join a motorway, cruise at 70-75mph for 30 miles or so, you will be knocking on the door of 50mpg. On short runs where you don't get above 40mph, or go far enough to move the temp needle, you won't get much more than 30mpg. Do something in the middle ground between these two and your MPG will follow the same trend. I can't imagine there will be massive differences between the MPG these cars will deliver out of the box, just massive differences in how we use them.

[Welshbeef]

I drove 3 miles from Reading train station home this evening - it’s uphill all the way. About 4 sets of traffic lights - which were all red

I just happened to remember that in doing that I managed 33mpg. No I wasn’t racing about simply driving to 30mph from a cold engine up a hill in congestion traffic.

That’s a 535d F10 in what 8-10 ambient temps.

OP if you are getting such dire MpG in the 435d can you qualify it and state what Mog you had in a previous car + what car that was.... it might be you drive it very hard which might be explained by this Or maybe you are still getting used to driving a diesel over a petrol it’s different so still learning how to get the best out of it. Or it’s faulty be it the Obc or maybe you have a fuel leak?


OP are the brakes binding?
Are the tyres inflated to the correct pressure

[Fox-]

Welshbeef said:

I drove 3 miles from Reading train station home this evening - it’s uphill all the way. About 4 sets of traffic lights - which were all red

I just happened to remember that in doing that I managed 33mpg.

Oh its Welshbeef and his magic 535d again

[chrisski.x]

Driving normally, driving spiritedly, mpg is at worst 30mpg. My tyres are meticulously all correctly inflated after destroying one of the runflats same week I bought the car from BMW Ashford after they handed it over with all four tyres under inflated. Was managing 27mpg under inflated.

Right now I am in eco warrior mode when driving just to see what I can manage - and I'll get all the stars from the efficient dynamics driving style analyser in a 20 minute drive.

Car immediately previous was Passat CC 2.0 diesel 170bhp with DSG, never bothered trying to max out the mpg on that and averaged 42mpg indicated. Before that a Lotus Elise 111S, 45mpg calculated on tank refil whilst having fun. Before that an Audi A3 1.9 130bhp, averaged 40mpg, ragged it everwhere. Before that a Corrado 2.9 VR6 190bhp, drove like it was on fire and got 28mpg. Before that didn't know what mpg was!

My natural driving style is mechanically sympathetic and quite smooth, only brake when necessary and reduce steering angle where possible (go karting days never leave me - similar racing style to Jenson Button, it has been noticed). I ease off the power as much as possible and lift early for braking.

[Welshbeef]

Fox- said:

Welshbeef said:

I drove 3 miles from Reading train station home this evening - it’s uphill all the way. About 4 sets of traffic lights - which were all red

I just happened to remember that in doing that I managed 33mpg.

Oh its Welshbeef and his magic 535d again

It didn’t cross my mind to take a picture of that.

Later today I’ve a drive single lane Then B road then dual carriageway about 30ish Miles. It will be 37-42mpg traffic flow dependant (ie hit a section of traffic lights or long exit from a junction will pull it down a touch.

I don’t drive with economy in mind period.