[bmwarchitect]

Originally Posted by Jon D

Consistent short runs like that will be harmful for any engine regardless of fuel type.

I need to get an office further from home then.

[bmwarchitect]

Thanks Johnbmw6 and JonD for the responses.

[JOHNBMWM5]

Originally Posted by HighlandPete

Not the best of trips, but see you have a petrol, so probably the best engine for faster warm ups. But not sure there is much you can do, conditions dictate your use.

HighlandPete

Good point and I would agree, conditions dictate usage.
Not much anyone could do in your commute.

[JOHNBMWM5]

Originally Posted by Jon D

Interesting what you say about combustion knock - when pressing on, without engaging kick-down, my 535d emits a lovely low end rumble, very reminiscent of the older Jaguar AJ6 engines. It's only when I begin to floor the accelerator that I notice a bit of a clatter, which I incorrectly interpreted as injector noise - if that were the case it would be present at all engine speeds and, on reflection, probably more audible at lower revs.
This is only my second diesel and I find it significantly more refined than the 330d unit in my '08 E92, but they're both extremely impressive engines.
Who would have thought, 10 years ago, that a diesel engine would get you to 60mph in less than 6 seconds and return over 40mpg!!!

Off topic, but I think you have chosen the best engine for UK use Jon, especially if you cover bigger mileages.

[Jon D]

Originally Posted by bmwarchitect

I need to get an office further from home then.

Ha-ha, why don't you just move house instead .
Joking aside, if you did a decent long run every weekend, you'd burn off a lot of the accumulated condensate and largely offset the corrosion damage - you'd also get to enjoy the car.
And, before you mention anything about additional fuel costs - bear in mind that you're talking to folk who pay nearly three times what you do per gallon .

[HighlandPete]

Originally Posted by gatoman39

In terms of long term reliability, are there certain mechanical parts of the drivetrain that need more attention if a diesel is driven in this manner? I'm under the impression that fuel system components, mainly filters and water separators need more attention than petrol versions.

It is more the contamination inside the inlet manifold, EGR valve, inlet valves, etc. Here in the UK experience shows that in urban driving, short runs, particularly from cold, particulate matter can build up to the point EGR valves are completely gummed up. In extreme examples, inlet valves have been so carboned up, that you can even lose compression and need a decoke. It also seems to be made worse, as we can have periods of relatively high humidity and that just adds to the mix, making more sticky stuff.

On examination of some engines, the top end looks as if they are full of tar. The muck, goo and wet carbon deposits just tells you the engines are being run under inappropriate conditions of use.

HighlandPete

[grimlock]

Originally Posted by HighlandPete

It is more the contamination inside the inlet manifold, EGR valve, inlet valves, etc. Here in the UK experience shows that in urban driving, short runs, particularly from cold, particulate matter can build up to the point EGR valves are completely gummed up. In extreme examples, inlet valves have been so carboned up, that you can even lose compression and need a decoke. It also seems to be made worse, as we can have periods of relatively high humidity and that just adds to the mix, making more sticky stuff.

On examination of some engines, the top end looks as if they are full of tar. The muck, goo and wet carbon deposits just tells you the engines are being run under inappropriate conditions of use.

HighlandPete

HighlandPete,

Does this apply to petrol engines?
I'm stuck with short city runs (3km, 10mins, lots of lights) given this, by the time im about home, the engine has just hit ambient temp, should I use the last bit of road to 'blast' the engine to 5k-6k (N52, peak HP@6600) and then turning it off 2mins later, or would i be better served just driving it normally?
Today was particularly humid, felt really sluggish..

[HighlandPete]

Originally Posted by grimlock

HighlandPete,

Does this apply to petrol engines?
I'm stuck with short city runs (3km, 10mins, lots of lights) given this, by the time im about home, the engine has just hit ambient temp, should I use the last bit of road to 'blast' the engine to 5k-6k (N52, peak HP@6600) and then turning it off 2mins later, or would i be better served just driving it normally?
Today was particularly humid, felt really sluggish..

We used to hold the view that short trips were worse for petrol engines than diesel, as enriched petrol fuelling 'washed' the cylinder bores. Whereas in diesel it didn't. Fuelling in the petrol engine is now far more controlled on the warm up cycle, and much faster than the diesel. So the diesel now looks the poor cousin, when you make short trips, particularly from cold. Emission control through EGR, makes the diesel a sitting target for getting overrun with gunk.

Simply put, big engines are not at all ideal for short trips and urban running, particularly in colder climates and/or colder seasons. The smaller the engine, the harder it has to work, is in its favour. IMO, a petrol wins, as the best engine for urban driving at present.

HighlandPete

[Jon D]

Originally Posted by grimlock

HighlandPete,

Does this apply to petrol engines?
I'm stuck with short city runs (3km, 10mins, lots of lights) given this, by the time im about home, the engine has just hit ambient temp, should I use the last bit of road to 'blast' the engine to 5k-6k (N52, peak HP@6600) and then turning it off 2mins later, or would i be better served just driving it normally?
Today was particularly humid, felt really sluggish..

You should most definitely not blast the engine until it's reached normal operating temperature. Why not go for a longer run and open it up when it's properly warmed. Afterwards, drive sedately for a couple of miles to allow oil, coolant and turbo temperatures to stabilise before shut-down - this is better than sitting at idle as you have no forward motion air flow through the engine compartment.

[grimlock]

Originally Posted by HighlandPete

We used to hold the view that short trips were worse for petrol engines than diesel, as enriched petrol fuelling 'washed' the cylinder bores. Whereas in diesel it didn't. Fuelling in the petrol engine is now far more controlled on the warm up cycle, and much faster than the diesel. So the diesel now looks the poor cousin, when you make short trips, particularly from cold. Emission control through EGR, makes the diesel a sitting target for getting overrun with gunk.

Simply put, big engines are not at all ideal for short trips and urban running, particularly in colder climates and/or colder seasons. The smaller the engine, the harder it has to work, is in its favour. IMO, a petrol wins, as the best engine for urban driving at present.

HighlandPete

Thanks for the insights.. alas no diesels here unless its has a black-out passenger comparment (-benz Vaino van, Range Rover freelander td4 etc.)
but they have the advantages of much lower first registration tax and fuel is 1/3 the cost.. still only permitted for 'commercial' use, though some people are doing dual-use..

[grimlock]

Originally Posted by Jon D

You should most definitely not blast the engine until it's reached normal operating ctemperature. Why not go for a longer run and open it up when it's properly warmed. Afterwards, drive sedately for a couple of miles to allow oil, oolant and turbo temperatures to stabilise before shut-down - this is better than sitting at idle as you have no forward motion air flow through the engine compartment.

Yeah, thanks -I generally get the principles of what to do/not to do.. I drive at 2k rpm or below intially, then to 3-3.5k from 70C on.. I was wondering if a short 'blast' was better once I had reached 100+, which would further boost the temperature before an inevitable shutoff quickly after, versus not doing the blast which would not further increase the temp. before I had to shutoff..

I do have the temptation to drive around for the sake of it, and do, but I still have to justify doing it to myself everytime .. I WISHED I lived further

I turn any 'Sport+' transmission mode off once im in the carpark, the needle falls to 1k and below for the last 1-2 minutes.. I do everything I can to coddle the baby

[indus]

Originally Posted by sliced

No it remains same.

Which diesel have you owned mate?