I was the same on my 535d, 26mpg, temps of 75. Changed both and now at 92 and can acheive 40mpg

EGR is a doddle to change.

 

Ok - got to be my next step then . Thank you .
I pretty much had the egr stat off when I was doing the main stat too . !

 

My 525d averages 33mpg. Just bought main stat and egr stat. Just looking for break in weather to fit the bad boys!

 

Agreed - change the other stat - its imperative that the car runs at the right temperature.

I also found that a failed glow plug controller affected my mpg adversely

Also ensure there are no boost leaks etc

 

The egr stat has just turned up so I'll be fitting it after work and going for a drive to test .. Hopefully my coolant temp should return back to normal .

 

Update - fitted the egr stat today , bled the system again and ran it up to temp and straight away it was up to 70c , so I went out for a short roadtest , 5-6 miles and only average 18 mph and mpg was climbing fast already and temp was at 88 and did get to 92 .
Chuffed it's sorted and thank you for your input

 

Hey Davey - check that it holds this temp on the motorway too - it sounds quite weird that your temps still stayed that low with a brand new main stat. If at motorway speeds it doesn't hold 88c then it could be the thermostat in the gearbox oil cooler, if yours is an auto.

Also it's advisable to take it for a long run (30 mins minimum) so that the DPF can regenerate which it wouldn't have been able to previously with the poor stats, so the dpf could potentially be blocked up.

 

Ok cheers - i t's a manual -
Not had the chance to go out for a proper drive it in but guess the dpf would be pretty blocked as been running low temps for a few weeks now ..

 

Glad you got your problem sorted.

Can I ask a really basic question please and ask how to get the temps up for viewing, and what temps should I be looking for? I've just bought an 08 E61 so just want to make sure everything is OK.

Thanks

 

https://www.youtube.com/watch?v=envKMwftf6w


the button has three "modes" a long press at 10 seconds, a medium press at 3 seconds, and a quick press at 0.5 seconds

 

I think this query has been done to death, but here it is again.
You can get the coolant temperature from the "hidden" OBC function 7.0 by using the instructions at http://www.scoopz.com/m5board/E60_Hidden_OBC_Instructions.pdf.
I was somewhat ignorant about this stuff before I started looking at the various BMW boards, but had sorta noticed that the little bars on the tacho were not going as far towards 5000 rpm as when I got my car, so decided to have a look. On a town/motorway run for 30 mins, temp was 64 - 68 degrees Celsius, which is, frankly, rubbish. Consenus here and elsewhere is 91 - 95 when properly warmed up. Got the famous excessive emissions warning, and insisted on getting the main thermostat changed whilst having the Air Mass Sensor changed (the fault reported by the computer), and now see 93 - 98 and impressively greater range for my £30 of diesel per week. Really, the thermostats should scream that they are going duff, but they don't.
Of course, no good deed goes unpunished, and the latest thing is impressive clouds of white smoke and vanishing coolant, no doubt related to the higher pressure in the cooling system. In a just world, this will be an EGR cooler failure, not a head gasket; I'll keep you posted.
G.

 

And something to add:
I might be pulling this one out of my arse, but here's a theory:
With the car now running at 90-odd degrees coolant temperature, the EGR thermostat has decided to open (at 77 degrees IIRC) and remained open, 'cos it's buggered. This, in turn, has revealed the annoying fact that the EGR cooler is leaking (as confirmed by my local specialist, via pressure test and bypassing the EGR cooling bit), hence the white plume, as if the car is celebrating the election of a new pope. This is good, since it discounts the alternative head gasket blown possibility, which would be v. uncool.
To sum up, white exhaust plume, capable of reminding following drivers of Dickensian London in the fog, car nonetheless running smoothly, but coolant disappearing mysteriously without any visible sign of leaking, then perhaps suspect the EGR cooler before anyone is advised that it must be a head gasket and ££££££££££s.
G.