BMW Diesel Engines & short commutes
 

Never owned a diesel in my life but still really fancy moving to a 6 cylinder X3 next April (so N57 engine) as a balance of practicality and decent grunt. They only come with Diesel engines these days (looking at 1yr old F25’s so pre facelift). Fancy a 35d but pretty hard to find in the right colour, conditions, options 2nd hand so I think a 30d is the better buy.

I have yet to find anything that fits the bill as well as the X3 in terms of aesthetics, size (don’t want anything bigger) and performance. Q5 I hate the look of, Mercs are too pricey, Land rover too big unless Evoque which is style over substance & not practical (boot space is a joke) plus too many tales of poor reliability. Very little else out there that has decent engine options. Infinity ugly as hell.

My one worry is that I currently do a max of 10k miles per year and my daily commute is just 8 miles each way. I read a lot of stories about diesels in general don’t like that kind of usage as doesn’t generate enough heat for the DPF to regen etc. That said my mate has a Golf GTD that’s does 30k+ a year and spends most of the time on the motorway yet he has DPF issues at 150k anyway. I don’t normally keep cars more than say 4-5 years and I doubt the X3 will be an exception. So do I really need to be concerned if I am unlikely to keep the car past the age of 5/6 years?

Whilst I am at it doesn’t anyone know a decent forum for X3 reading? Bimmerpost, bmwoc, bmwland seem very quiet indeed.

I lasted six months with my first diesel before reverting to petrol version of the same car. I get 2/3 of the economy on the petrol but more than double the power.

I have a 14 mile commute and the modern diesel and petrol both reached 70C oil and 90C coolant temperature in 4 miles gentle driving from cold at around 15C ambient.

One reason I bought the diesel initially was the lack of choice of petrol engines and with the cars you are looking at I suspect you may find the same even if you want petrol. Additionally, for a non performance model, the petrol will likely be difficult to sell on or depreciate more. When I found a way into a petrol with right economics and deal I jumped at the chance.

If you are like me though, avoid four cylinder diesels at all costs, and avoid normally aspirated petrol engines as they feel gutless unless massive after a diesel. I found a nice sounding diesel six can sound nearly as nice as an average petrol six. Didn't find difference in throttle response. Diesel longer geared but even late German sixes still aren't as smooth as equivalent petrol.

The very latest EU6 diesels are likely to have adblue and be allowed in more city areas in future with others attracting taxes. Feelings are mixed on the DPF/EGR/ultra high pressure injection reliability.

I've had an F25 2.0 SD X3 for 3 years now, previously had an E70 3.0 SD X5.
Loved the X5, felt very solid, handled more like a sporty estate, and didn't feel as big as it looks. Went for the X3 largely to save some money. It doesn't feel as solid as the X5, couldn't see me power sliding it out of a roundabout like the X5...
My daily commute is 11 or so miles each direction. Now done 45k miles, only problem has been a front wheel bearing. Fuel consumption is typically low 40's, did manage low 50's once as an experiment but it was hard work..

Pretty much every modern diesel wont like short journeys, they are designed to get hot and stay hot, doing short journeys will just fcuk them up compared to a petrol car (as in short journey I mean similar to yours, 2 miles each way will screw even petrol engines up if thats how they will be run).

You are probably going to be better off running a petrol for the mileage you do (saying that, i do about 12k p.a. in my diesel but most of my runs are 200+ miles in one go).

Tony:)

You have a golf as well
That does high mileage?
I take it your wife drives that? Just get her to take the bmw once a week so it can regen

Whats the SD designation mean as not come across that? Surely the lack of grunt from the 20d unit (in comparison to the 30d at least) is half the reason you cant power slide?

Low 40's would be a revelation for me as currently get mid 20's :)

Normally the wife and I just use our own cars (mainly as she is afraid of kerbing my wheels. But if we bought an X3 it would be the main car so I guess would end up doing all the long trips.

What I was getting at is should I really need to worry about such issues with diesels in the first 5-6 years of a cars life? 2yrs of which is gonna be under warranty.

No that is a friend who stays with us during the week. His is ultra high miles (155k on a 58 plate GTD) so an extreme example and he does tend to drive it like he stole it.

Kia sportage with petrol engine, problem solved :thumb:

All Diesel engines now come with tight emission control kit, meaning they will clog up quick on short journeys. The more short journeys you do, the faster it will get worse until you no longer have comparable performance to when you first bought it

If you're happy to be cleaning EGR's, Variable Vein Turbos, DPF's and the intake manifolds - your diesel will be fine on short journeys.

If I was you, I'd stick with petrol, you'll save a lot of time and hassle in the long run, even if you only keep it 3 years.
If you're worried about road tax/low mpg, look at at the new Lexus RX Hybrid models, they still shift and higher mpg with none of the diesel downside - Depending on the V8 installed, you can even supercharge it.

I think SD's are the 2WD versions.

My mistake, it's just a 2.0d, the X5 was an SD, I'd just assumed the model names were the same.

The X3 just feels altogether more fragile than the X5, both cars had the dynamic suspension/wheel package, but the X5 felt indestructible and it was driven very hard for 60k miles, only failures were front wheel bearings.

sdrive are indeed but no sdrive avail on X5 or 3.0l models hence my confusion :)

2WD with a 1.6 pushing out 133bhp. Moving on.....

Not a great fan of Lexus aesthetics but was intrigued about the engine options you mentioned. Only RX I see is the 450h which appears to be the same 3.5 litre V6 engine on ally variants and the performance data not that inspiring (almost 8 secs 0-60).

Not really looked at the X5 as seems to big and the wife not keen on something that size (drives a 3dr Rav4 currently).

How do you find runflats as a lot of negative talk online but tbh I found it perfectly acceptable. Only test driven the latest 20d M-sport (2014 version with slightly more power, better base spec) which I believe was on the 18" wheels with run flats. That said I am currently driving a Focus RS MK2 on 19's and eibachs so I guess it depends what you are used to.

What do we class as a short journey - or more to the point, what is the minimum distance a derv should go to get properly warmed up?

And of these short journeys, at what total mileage should you see a knackered Diesel engine?

Good question.

My 330d is 7 years old in December and was on 78,000 when bought in July. Now on 83,000. I do a good run (say 100+ miles every couple of weeks or month at worst) in order to regen it. During the week it does mostly 2 mile runs to work and 11 mile round trips picking up /dropping off the mrs from work.

To be honest it seems ok with that. Been tempted by a 330 petrol but I like the turbo pull, masses of torque and higher mpg from the derv. It's very smooth too so god knows how good its petrol variant is!

I'm thinking after having had it a year, get the DPF innards cut out, and a cheeky remap. :)

Stick to a Toyota, absolutely no reliability probs at all there

Are you saying you get in the car and do 100 mile plus drive - just to "regen" some bit of the engine

Sounds a bit crazy to me - and a bit of an ownership commitment tbh

Nope. I usually find an excuse for said drive, ie a family day out / weekend away, online purchase like vinyl records etc.

The only thing that has a commitment problem is the follicles on my head :(

Sorry :( I know it's similar to the GS450H which is a saloon, petrol hybrid and gets to 60mph in 5.9 seconds. I expected the RX450H to be somewhat similar.

There is an NX 2.0 Turbo coming out next year which could be modified, but supposedly 7.1 seconds to 60mph from standard.

Outside of Toyota/Lexus, all out of ideas for high mpg that isn't diesel. High mpg and high performance don't generally go together unless it's a dirty diesel :lol1:

The runflats on the X3 are a Pirelli P7 summer tyre, they're rubbish on cold slippy roads and downright dangerous on ice or snow - Pirelli do make a winter version but not sold in the UK. The X5 had Continental runflats and they were fine in all conditions, including snow and ice, and we live in rural N Scotland so see plenty.

The X5 looks big but never felt big - possibly down to the good visibility from the driver seat? We tried the Q7, Touareg and X70 and they all felt huge in comparison.

My wife loved driving the X5, and even towed someone out of a ditch one night, she misses the X5 more than me - although she's now stopped using the X3 as she's just bought a Mini Paceman which has the same engine as our X3, albeit only with a single turbo.

Ah, ok thought so - just checking, lol

I bet there are some people that do though - nowt strange as folk

Interesting thanks. Even if I could talk the mrs into an X5 it would be a step too far for our £35k budget.

It seems that there's new laws on the horizon with regards to diesels. There now talking about a scrappage scheme and a higher congestion charge but either way the pressure is building.
I suppose it wouldn't be too much of a stretch to imagine the government raising the car tax and fuel prices for diesel which would in turn affect resale prices.

We ran a F07 530d for almost 3 years where its daily commute is roughly 4 miles each way. No DPF issues. That includes plugging in the car in and checking codes and live data for last regenerations and exhaust back pressure just to make sure it was happy.

HOWEVER....it does get a run at least once a month to the airport...and a few round trips to Spain and back about three times a year) . And I think that's the crux - as long as those short journeys are broken up by the odd run once a month it'll be fine.

The other crux is if the engine is running properly...if something causes it to produce smoke - which you won't see (as the DPF traps it first). It will have DPF problems sooner or later. Even if it has no warnings on the dash and appears to perform fine, and it'll continue to do so, until the fault worsens to the point that you get check engine warnings and car goes into limp home. The same applies if the car is neglected with incorrect/poor maintenance like using the wrong oil (non SAPS), or allowing the oil level to rise from fuel dilution (or overfilling).


As a personal example, I've just swapped the 530d for a 535d....no warnings on the dash (or iDrive), no real performance issues to the uninitiated. BUT its doing 33mpg on motorway journeys that the 530d would do 40mpg (both N57 3.0 engines so MPG should be very similar). Clearly its not right, low and behold, I plug it in and find there is a intermittent issue with a bypass valve (damper) which is responsible for the control of the turbos.

Its likely if I carried on driving the car in this state where the fault becomes more frequent, it'll get to a state where it stops the DPF from being regenerated or it has to regenerate alot more frequently than normal, I'd have a DPF issue not before long. The point at which the car will tell me there's a problem will be when the check control message will bling at me saying the DPF is clogged. I've noticed/caught the problem before it manifested....many drivers wouldn't be so observant.

Point being, DPF problems is almost always the symptom of a underlying fault, it very rarely the cause.

The other point a DPF regen does NOT take 100miles, forums spouting this nonsense really doesn't help, and just serves to waste fuel and time. All it needs is the engine at operating temperature, once up to temperature the process is finished within 5 miles and without exceeding 50mph (or 30mph in some cases).

It takes longer for the engine to warm up, and that's a main issue. Be it a Focus, Jag, or a BMW or whatever (ignoring the oddball exceptions - a C-max will automatically regen with a cool engine :cuckoo: ). Obviously if the car has a faulty thermostat (very common on BMWs), it'll take ages to warm up enough to regenerate, which brings me back to my earlier point about being nothing wrong with the engine.....

When I owned my Golf I felt like I would have been better off with a petrol rather than the TDI. I had no complains in terms of performance or reliability (although the 'threat' of high pressure pump failure was always in the back of my mind). The issues was - as has been alluded to - the fact that I tended to only do short runs and the diesel would spend a significant amount of time not up to temperature. Plus there was the DPF concern of these short runs.

Have the last few days been thinking about getting a car again, and the second hand availability of petrols is much lowers, so may be forced again to go diesel.

As in post #2, I am finding diesel and petrol warm up exactly the same on the same roads driven similarly in almost identical cars except the engine, but this is 2013 engines so cylinder shutdown on the petrol, direct injection on both, fast warm up tech on the diesel.

The diesel was doing 50% better economy on 14 mile trip of which 4 miles was warm up. Petrol is 33% bigger displacement and cylinders though.

I bought a diesel when I really wanted a petrol due to lack of choice, but the chance to swap unscathed came up. I would buy what you like to drive unless doing really big miles. Personally I prefer a good four cylinder turbo diesel to most four cylinder normally aspirated petrols except the noise. Petrol turbo is my favourite.

At risk of asking a dumb question... how do I know that a DPF regen needs doing, or has happened, or is in the process of happening?

I have an F10 530d, which generally gets used for a couple of short trips each week, but every few weeks I'll visit a customer 50 or 60 miles away so it gets a much better chance to warm up and stay at motorway speed for a while.

Should I expect to see a warning come up on the instrument cluster? Or feel a significant change in the engine's behaviour?