[E92westy]

My car is a 2007 E90 320d (163) with 44,000 miles on, FSH.
I've been reading various threads on here and elsewhere about EGR stats and main stats failing.
I've had some pretty shocking MPG (29 - 33mpg ) recently, so wondered if this part of my problem.
I've done the 'hidden menu' trick and generally it takes over 15 minutes for the temp to break 80C.
It does get up to 86, but can fall back to around 83 on downhill or 'easy' load sections.
My commute is 20 miles each way pretty mixed rural / urban but no motorway, average overall speed shows around 30mph on the OBC).

Should it be warming up quicker and if so is the EGR stat the likely culprit.

Thanks!

[jimmylad]

I dont think thats too bad to be honest. ( temperature wise)

Try resetting the computer on the motorway & stick to say 70 for 10 miles. If I did that on my 335d I would get at least 45mpg. Probably nearer to 48.

You should get well over 50mpg I would have thought doing this. If you dont then something must be wrong.

I have a transit that will do 40mpg easily provided you dont floor it.

Seems to be getting more common on the 320d's

[Jeff123]

Problem is that the BMW headline MPG's are ridiculously high. People look at the 320d and see the 58.4 MPG (or whatever) and expect to achieve this figure.

Like the previous poster says, that's a good way to test the car.

Another interesting test (bit sad really) is to zero the MPG for the outward trip and drive really steadily - see what the MPG is. Then, repeat the procedure on the way back and drive it hard.

[E92westy]

Thanks guys.
I never had less than 44mpg out of my previous Audi A4 (PD130) whatever the weather and frequently got 50mpg on the commute in the summer.
The 320d was 41mpg from day one (August), dropping to 36ish when the cold weather came in.
Now it's 32 if I'm lucky...
That's worse than the execrable 320i I had.

[kowalski]

irrespective of mpg achieved, temperature is what mine gets to. I was also worried it might be down to a faulty thermostat but I was assured by the garage (specialist) that operating at 80+C is normal. According to them when the stat goes you'd struggle to see 70C under light load (motorway driving)

[YvesD]

Water temp guages are next to useless unless you know the correlation between that and real time oil temp which is the critical thing.

Judging by other cars I travel in on the same road, water temp is up to normal operating range in less than half the time the oil is.....

In the current cool temps, 12 - 15 miles on mixture of Nat speed limit and town roads before my 335i's oil is at the correct temp for hard work...

On really cold days, it doesnt warm up properly in the whole 12 mile commute!

Cheers

Yves

[beemerbird]

Originally Posted by YvesD

In the current cool temps, 12 - 15 miles on mixture of Nat speed limit and town roads before my 335i's oil is at the correct temp for hard work...

Out of interest as I'm back in a petrol engine with a turbo, what is the normal oil running temp of your car and what you perceive as warmed up?

[YvesD]

Originally Posted by beemerbird

Out of interest as I'm back in a petrol engine with a turbo, what is the normal oil running temp of your car and what you perceive as warmed up?

According to the oil temp guage itself, 70c is where it actually starts reading and the technical blurb says 'normal' operating temps are between 100 - 120c.

I usually see 110c ish in the summer, never seen it as high as 120c.

Cheers

[briers]

Hello mate,

It seems about right. Takes me about 15mins to get from stafford castle to shugborough, across town. By that time its mid 80s, like you say, it can drop a little on light loads.

Mpg seems a little off. My commute is also 20 miles each way to lichfield, avg speed 31 atm. 42.1mpg. Is there a lot of junctions on your route? Mine is extremely dull and everyone bunches up in the dark, so its a steady pace.

[E92westy]

Originally Posted by briers

Hello mate,

It seems about right. Takes me about 15mins to get from stafford castle to shugborough, across town. By that time its mid 80s, like you say, it can drop a little on light loads.

Mpg seems a little off. My commute is also 20 miles each way to lichfield, avg speed 31 atm. 42.1mpg. Is there a lot of junctions on your route? Mine is extremely dull and everyone bunches up in the dark, so its a steady pace.

Hi Ben,
Worrying thing is you've got a 335d and I've got a 320d with worse consumption!
Yes, it can get a bit slow at the 'business end'.
I've got an OBD2 gizmo bought for another motor, so perhaps I'll try a few logs and post them up.
Might change the EGR stat anyway as it's seems cheap and pretty easy to do.

Bring on the summer!

[HighlandPete]

Winter warm up times can be quite extended. Oil temperature even more so.

We have a VW Caravelle TDi in the family with an oil temperature gauge (and digital read out). It can take 16 miles to reach optimum oil temperature, when the ambient temperature is around freezing point, and that is driving about 55 - 60 mph. Get even lower temperatures and the oil temperature will drop off when running idle, during the warm up period.

To the issue of EGR thermostats being the main issue for slow warm up, certainly there are failures, but the EGR' stat in itself may not be at fault. I thought my car was compromised on warm up, by a faulty EGR 'stat, but after replacing (original was just a few degrees down on opening) there is virtually no difference in the warm up times. My car also runs mid 80's when up to temperature. Obviously a few degrees low of the main thermostat rating of 88C, but seems very typical of many of the engines both in our BMWs and in the Rover CDTi, with the M47R engine.

My car will take over 12 miles to get to 85/86C, when at low ambient temperatures around 0 - 5 degrees. That's running at about 60mph, with a slow down to 30mph after 3-miles, Will then drop off to about 83C if runnning idle, or very low loads.

At 8C ambient, engine heats within about 7 miles and the engine will stay at 85C on idle, once warm. Not yet had any higher temperatures to test.

The ERG 'stat really needs checking, as a faulty one will typically 'blow through' at room temperatures.

HighlandPete

[JaySTee]

I also have a 2007 E91 320d. I have found that having the heater on at this time of year can make quite a difference to the warm up times on my short commute. Without the heater it takes 10-15mins to get up to 80ish and then will get to 85 but generally not much higer and will drop back a little when going down long hills or idling.

Judging by what everone else says and reading elsewhere i'd say your (and my) temps are about normal so maybe there are other factors to your poor consumption? I have hear people mention injectors, coked up EGR valve, maybe even if the airfilter needed changing, faulty MAF?

Reading other threads on here about poor 320d fuel consumption it seems even BMW dealers have difficulty sorting it out...

My fuel consumption just for my commute was arount 37mpg in the freezing weather. I haven't reset it for a while and it has settled to about 41.5 mpg with a few longer journey's thrown in.

[E92westy]

From this morning, fairly decent run in.
45 minutes journey, average speed 33.5mph, average consumption 34.0 mpg.
Ambient temperature around 4C rising to 5C.
Did connect the OBD logger, but got the settings wrong so no log file saved - plonker!

Will try again.

I've booked it in the dealer next week for a looksee anyway.

Cheers.

[HighlandPete]

Originally Posted by JaySTee

I also have a 2007 E91 320d. I have found that having the heater on at this time of year can make quite a difference to the warm up times on my short commute. Without the heater it takes 10-15mins to get up to 80ish and then will get to 85 but generally not much higher and will drop back a little when going down long hills or idling.

I posted the following this morning, in a parallel topic on BMWLand.

I use a fan heater to thaw out my car and preheat the cabin a little, on freezing days. That makes a difference as well, to the warm up times. The heating system, on a cold day, will run at near full speed for several miles and I'll still have 4-bars on the display, at about 8 miles. With the pre warm up, the heater doesn't go to full speed and/or cuts back much earlier. Plus the electric PTC heater element won't be demanding as much energy either.

From my experiments, cabin heating has a large part to play on warm up and mpg figures, on cold days. Would be interesting to know how many kilowatts/joules we use from the fuel (with all the inefficiences of energy conversion) during the cabin warm up phase. I know 2kW (direct heating) for 30 minutes does warm the air and thaw the windows, but still not a stable cabin temperature.

Certainly the total differences of varied starts are quite striking.

HighlandPete

[satish_141]

Originally Posted by HighlandPete

Winter warm up times can be quite extended. Oil temperature even more so.

We have a VW Caravelle TDi in the family with an oil temperature gauge (and digital read out). It can take 16 miles to reach optimum oil temperature, when the ambient temperature is around freezing point, and that is driving about 55 - 60 mph. Get even lower temperatures and the oil temperature will drop off when running idle, during the warm up period.

To the issue of EGR thermostats being the main issue for slow warm up, certainly there are failures, but the EGR' stat in itself may not be at fault. I thought my car was compromised on warm up, by a faulty EGR 'stat, but after replacing (original was just a few degrees down on opening) there is virtually no difference in the warm up times. My car also runs mid 80's when up to temperature. Obviously a few degrees low of the main thermostat rating of 88C, but seems very typical of many of the engines both in our BMWs and in the Rover CDTi, with the M47R engine.

My car will take over 12 miles to get to 85/86C, when at low ambient temperatures around 0 - 5 degrees. That's running at about 60mph, with a slow down to 30mph after 3-miles, Will then drop off to about 83C if runnning idle, or very low loads.

At 8C ambient, engine heats within about 7 miles and the engine will stay at 85C on idle, once warm. Not yet had any higher temperatures to test.

The ERG 'stat really needs checking, as a faulty one will typically 'blow through' at room temperatures.

HighlandPete

Hi Pete, we discussed this before, but for the benifit of others what I want to say is, my 320D even after driving for 50 miles on the motor way that coolant temp only stays between 79C to 81C in winter. Its never gone past 81C which I think is pretty low! but having said that now after the temp reached double digits I am getting 550 to 600 out of a full tank which works out to be 41 to 42MPG combined driving which I think is good enough. So I am slightly confused in the sense that if my coolant temp is lower than normal then I shouldn't be getting 40+ MPG combined...?

[HighlandPete]

Originally Posted by satish_141

Hi Pete, we discussed this before, but for the benifit of others what I want to say is, my 320D even after driving for 50 miles on the motor way that coolant temp only stays between 79C to 81C in winter. Its never gone past 81C which I think is pretty low! but having said that now after the temp reached double digits I am getting 550 to 600 out of a full tank which works out to be 41 to 42MPG combined driving which I think is good enough. So I am slightly confused in the sense that if my coolant temp is lower than normal then I shouldn't be getting 40+ MPG combined...?

Low mpg as a result of lower running temperatures is again a variable. Not every one finds a change of mpg when the main thermostat is changed, but of course it could improve, if the driving conditions are influencing the mpg, at the lower coolant temperature.

For myself, I wrote:

I've not noticed any mpg drop off, but did a reset and typical run from cold at about 5C, and got 41.5mpg, typical of the mpg for the run at low temperatures. So I've not seen myself as having any temperature problems. But thought I'd run a couple of checks anyway.

Now whether I'd have a slightly higher figure for that 11 mile trip, if the thermostat was opening at 88C and the temperature peaked at 90C, I'm not sure. As at 5C ambient, the engine doesn't get to 85C in 11 miles, on that particular trip. But the main thermostat could be cracking open at around 82C in my car, giving me the 85C peak I see at the lower ambient temperatures. Now at 8C and constant running, I see 86C (and a peak of 87C flashed up for a few seconds), so I'm not yet sure when the main 'stat is opening, and how lazy it is to regulate once open.

I think a lot of the mpg issue, will be the warm up phase, and whether we get there as fast as possible in our driving, how many miles at decent heat values and/or we end our trip before we even get a stable temperature. There are so many variables to this, it is not a definite "new thermostats" and we get better mpg. Although we ought to fare better on thermostats which are working at optimum temperatures.

HighlandPete

[JaySTee]

Originally Posted by HighlandPete

I posted the following this morning, in a parallel topic on BMWLand.



HighlandPete

Good idea using a fan heater. Have you worked out the cost of electricity used verses the fuel of heating the car form scratch? Although I guess it must be nice getting in to a pre warmed car In colder places it is not uncommon to fit diesel fueled Eberspacher type heaters that you can opperate from a remote to warm the car up nicely before you get in with no need to start of even unlock the car.

[HighlandPete]

Originally Posted by JaySTee

Good idea using a fan heater. Have you worked out the cost of electricity used verses the fuel of heating the car form scratch? Although I guess it must be nice getting in to a pre warmed car In colder places it is not uncommon to fit diesel fueled Eberspacher type heaters that you can opperate from a remote to warm the car up nicely before you get in with no need to start of even unlock the car.

Interesting... ignoring the comfort factor and not needing de-icer, or idling the engine.

Three options...

1) 30 mins at 2kW @ 13.5 pence per kW = 13.5 pence per warm up.

2) Idling the engine can be about 1 l/hr when cold, (average for medium sized diesel is 0.54 l/hr when warm, at idle). Let's say 30 minutes to get the same heat from sub zero, if that is enough? Would be about 0.5 litre @ £1.34 per litre = 67 pence.

3) Reduced mpg for not pre heating, say it is a penalty of 2 mpg, (37mpg, down to 35 mpg in my case) cost of 1 pence per mile. So for 12 miles into town = 12 pence*

*Remember I wouldn't pull the mpg figure back to 37mpg on the return journey, so it is in fact more than 12 pence for driving straight off cold.

HighlandPete

[Dackelone]

Normally in the winter time you have two reasons why your MPG (or Liters/100kph)will go down:

1). The deisel fuel is blended differently to prevent jelling.

2). Winter tires (IF you have them mounted) have increaded rolling resistance.



Dackel

[JaySTee]

Is that the case in the uk - does it get cold enough to need different diesel?

[Dr Dave]

Yes, the refineries add cold weather additives to derv for the colder months automatically.

[beemerbird]

Originally Posted by YvesD

According to the oil temp guage itself, 70c is where it actually starts reading and the technical blurb says 'normal' operating temps are between 100 - 120c.

I usually see 110c ish in the summer, never seen it as high as 120c.

Cheers

Cheers for that.

Mine seems to stick at 102c when warmed up, all driving conditions. Will check over summer as I got it in the autumn.

This thread has become rather amusing though.