2014 ''efficient'' tax exempt Insignia ''eco'' flex getting 35-40 mpg. listed as 63-88 mpg .

[Bodgedbuild]

One of the biggest killers of fuel consumption on a diesel engine is a thermostat that allows the engine to run too cool. The gauge is not a good indicator for this as it shows a "feel good" reading, normally in the middle.
I would run the car from cold with an OBD diag tool plugged in and see that it reaches around 80 degrees. It should also get to 70 degrees + after around 5-7 miles.

 

[Harry Bloomfield]

One of the biggest killers of fuel consumption on a diesel engine is a thermostat that allows the engine to run too cool. The gauge is not a good indicator for this as it shows a "feel good" reading, normally in the middle.
I would run the car from cold with an OBD diag tool plugged in and see that it reaches around 80 degrees. It should also get to 70 degrees + after around 5-7 miles.

My BMW engine is very efficient, it is very difficult to get it up to temperature in summer and almost impossible in the winter - hence why they were fitted with an FBH. It also has the useless dash gauge, which simply shows a perfect running temperature, at any temperature between 70 and 110C.

 

[Bodgedbuild]

My BMW engine is very efficient, it is very difficult to get it up to temperature in summer and almost impossible in the winter - hence why they were fitted with an FBH. It also has the useless dash gauge, which simply shows a perfect running temperature, at any temperature between 70 and 110C.

If your BMW is one of the "F" models, the gauge will be an oil temperature gauge not coolant. Oil temperature takes far longer to increase than coolant so I suspect it will get up to temperature before the gauge indicates. I have no idea why BMW chose to do this, but there is a small legend on the gauge to show it is oil temp....

 

[Harry Bloomfield]

My theory, is that the crank case fumes and (in later life) whatever gets past the turbo seals, find their way into the inlet tract. At this point, they're just thick, slightly sooty oil. This gunge coats the walls of the inlet duct, including all the intercooler tubes. Running the engine at max. power, gets the airflow through the inlet tracts up to a maximum and (I believe) "scours" this stuff off the surfaces and into the cylinders, where it gets burned. Normally, Mrs Avocet drives quite gently, but I'd make a point of borrowing it at least once a month, and "giving it death" up a long steep hill a few times. The first time I'd do it, the car would smoke a fair bit (no DPF on it) and the second time, there would be less smoke. If this isn't done regularly, the hot EGR gas "bakes" it on to the inlet manifold wall, and you get the buildup you describe.

My theory is that it only becomes baked on, once the oil gets to the engine side of the EGR, where the exhaust meets the oil. Any oil before that will just be runny and drawn into the engine eventually. Crankcase fumes and oil go straight back into the intake, so I doubt they would have much effect.

The air flow system works like this - air filter> turbo >intercooler >EGR > manifold > inlet valves > engine. The hot exhaust gas is allowed to enter via a valve at the EGR, so only the parts marked in red suffer the burned on, carbonised oil choking them up at a tick-over.

My BMW engine has a reputation of being one of the very cleanest burn engines, especially if it is well maintained and driven with sympathy. On it's first MOT in my ownership, after I had brought everything up to standard, the inspector thought is emission measuring equipment had failed, because the readings were so very low and it was so very clean. It has continued to produce similar low readings at each yearly test.

My theory on why it runs so very clean, is down to the type of use I make of it, plus the fact that I maintain it. It almost never does, short runs, shopping trips or local trips. We find the bus much more convenient to get around locally - so it almost never gets stuck, ticking-over in traffic. In winter, when I intend using it, I tend to fire up the FBH to warm the engine up for 20 minutes before I start the engine.

A new company VW I had, which spent a considerable amount of time in traffic, had the EGR fail just 10K into it's life.

 

[Harry Bloomfield]

If your BMW is one of the "F" models, the gauge will be an oil temperature gauge not coolant. Oil temperature takes far longer to increase than coolant so I suspect it will get up to temperature before the gauge indicates. I have no idea why BMW chose to do this, but there is a small legend on the gauge to show it is oil temp....

No it is definitely a water temperature gauge.

 

[Bodgedbuild]

These are both F10 (5 Series) and F30 clusters and both are oil temperature gauges. I can only assume yours must be an optional spec model, digital dash or similar? I know that my F30 (320d with B47 engine) reaches about 80 degrees coolant temperature (using Carly OBD) before the oil temp on the gauge has crept much above the 50 degrees. A friends F32 with the same engine does the same. Both will run at around 90 degrees coolant (but 70-100 oil temp) once on a run however cold it is....

 

[Avocet]

My theory is that it only becomes baked on, once the oil gets to the engine side of the EGR, where the exhaust meets the oil. Any oil before that will just be runny and drawn into the engine eventually. Crankcase fumes and oil go straight back into the intake, so I doubt they would have much effect.

The air flow system works like this - air filter> turbo >intercooler >EGR > manifold > inlet valves > engine. The hot exhaust gas is allowed to enter via a valve at the EGR, so only the parts marked in red suffer the burned on, carbonised oil choking them up at a tick-over.

My BMW engine has a reputation of being one of the very cleanest burn engines, especially if it is well maintained and driven with sympathy. On it's first MOT in my ownership, after I had brought everything up to standard, the inspector thought is emission measuring equipment had failed, because the readings were so very low and it was so very clean. It has continued to produce similar low readings at each yearly test.

My theory on why it runs so very clean, is down to the type of use I make of it, plus the fact that I maintain it. It almost never does, short runs, shopping trips or local trips. We find the bus much more convenient to get around locally - so it almost never gets stuck, ticking-over in traffic. In winter, when I intend using it, I tend to fire up the FBH to warm the engine up for 20 minutes before I start the engine.

A new company VW I had, which spent a considerable amount of time in traffic, had the EGR fail just 10K into it's life.

Yes, but the oil can't GET to the engine side of the EGR to get baked on in the first place, without passing through those other bits first! I absolutely agree it doesn't get baked on to the inside of the intercooler, or the pipes leading to and from it, but that's not really the point we were discussing.

Also remember that they don't get "choked up at tickover", because demand for air is very low. It's at high power outputs when demand for air is high, that you notice they're choked up.

What BMW engine do you have? The Freelander uses the M47 engine. I don't remember those being regarded as particularly clean? They seem to have similar emissions figures to any other "Euro 3" diesel engine. It does have a FBH, but that's not because it's clean, that's because it's efficient and rejects very little heat to its cooling system. Lots of modern diesels have them, although they go by different names. The generic industry term is "combustion heater".

 

[cdbe]

When we bought our VW Touran 1.9Tdi it had quite a bad oil leak. It was 10 years old, 72k FSH, immaculate condition and I believe previously owned by a 'dodderer'.

The leak appeared to be from an intercooler pipe near the bottom of the engine. My wife has a complete lack of mechanical sympathy and caned the poor car everywhere - stopped leaking after a
month and hasn't leaked a drop in 21/2 years. Sails through MOT.

 

[Harry Bloomfield]

What BMW engine do you have? The Freelander uses the M47 engine. I don't remember those being regarded as particularly clean? They seem to have similar emissions figures to any other "Euro 3" diesel engine. It does have a FBH, but that's not because it's clean, that's because it's efficient and rejects very little heat to its cooling system. Lots of modern diesels have them, although they go by different names. The generic industry term is "combustion heater".

It is an M47 and utilises the very same radiator as the V6 petrol, so has a massively over capable cooling. I fancy it would almost work perfectly happily without a radiator at all.

 

[Bodgedbuild]

It is an M47 and utilises the very same radiator as the V6 petrol, so has a massively over capable cooling. I fancy it would almost work perfectly happily without a radiator at all.

The M47 is very prone to running over cool due to the EGR thermostat not closing fully assuming it is an E60/61 or E90, I even did a video of how to change it many years back...

 

[Harry Bloomfield]

When we bought our VW Touran 1.9Tdi it had quite a bad oil leak. It was 10 years old, 72k FSH, immaculate condition and I believe previously owned by a 'dodderer'.

Usually down to O rings rotting. Viteon are better able to stand up to the oil. I had leaks there and replacing with Viteon versions throughout cured it.

The leak appeared to be from an intercooler pipe near the bottom of the engine. My wife has a complete lack of mechanical sympathy and caned the poor car everywhere - stopped leaking after a
month and hasn't leaked a drop in 21/2 years. Sails through MOT.

I try to drive with some mechanical sympathy, but like to hammer it occasionally. When I take it for an MOT, I make a particular point of hammering it, 10 miles on a local motorway, then 5 miles of hooning it on country lanes, then the MOT. The back bumper is a good place to check for something amiss on a diesel, look for soot there.

 

[Avocet]

It is an M47 and utilises the very same radiator as the V6 petrol, so has a massively over capable cooling. I fancy it would almost work perfectly happily without a radiator at all.

One of the many things wrong with the Freelander when my sister handed it over, was that the thermostat was stuck open. It's a pig of a job on a Freelander 1. I picked the car up from where they lived in Monmouth in May, and drove it home to Cumbria. The temperature gauge was pretty much on the bottom stop all the way up, except when I booted it up Keele Bank on the M6, where it just about managed to drag its sorry ass up to maybe half way between cold and normal.

 

[Harry Bloomfield]

One of the many things wrong with the Freelander when my sister handed it over, was that the thermostat was stuck open. It's a pig of a job on a Freelander 1. I picked the car up from where they lived in Monmouth in May, and drove it home to Cumbria. The temperature gauge was pretty much on the bottom stop all the way up, except when I booted it up Keele Bank on the M6, where it just about managed to drag its sorry ass up to maybe half way between cold and normal.

Yep, that is a common failure and it is a specially made stat for the engine. A work around, was to push fit a more common stat into the top rubber hose. I think I heard a Renault stat fitted the hose with a bit of persuasion.

 

[Avocet]

When we bought our VW Touran 1.9Tdi it had quite a bad oil leak. It was 10 years old, 72k FSH, immaculate condition and I believe previously owned by a 'dodderer'.

The leak appeared to be from an intercooler pipe near the bottom of the engine. My wife has a complete lack of mechanical sympathy and caned the poor car everywhere - stopped leaking after a
month and hasn't leaked a drop in 21/2 years. Sails through MOT.

Lack of mechanical sympathy doesn't necessarily mean not caning a car! OK, doing it on a cold engine would be a bit cruel, but I've seen more engines killed by "kindness" than hard work. I've outlined my theory in Post#15 in greater detail, but I suspect the reason it stopped weeping, was because by thrashing it, she purged much of the condensed oil mist out of the inlet tract and burned it. In effect, she did the car a huge favour.

 

[Avocet]

The M47 is very prone to running over cool due to the EGR thermostat not closing fully assuming it is an E60/61 or E90, I even did a video of how to change it many years back...

Interesting. I don't have anything looking like that on the Freelander. It's probably the most basic EGR setup I've ever seen, so I suspect that was a bit Landrover did themselves.