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DPF - Diesel particulate filter, quite litterally a filter that removes lots of particulates then tries to reburn them when the ECU feels like it.

DMF - Dual-mass flywheel, until the last few years cars had solid lumps of iron that never went wrong, replaced by two pieces held together with springs, fail and cost a bloody fortune to replace. No, I've no idea why...

EGR - Exhaust Gas Recirculation, shoves a bit of exhaust gas back in to the inlet for emissions reasons.

That's from another Cambridge* man!

Cheers,
Andy

*Born in Cambridge but bought up in Haverhill, but please don't judge me!
 

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Discussion Starter #22
Ok, so the DFP and EGR issues mentioned in this thread aren't much of an issue as they are cheep to repair. But, the DMF sounds iffy. Is that in the gearbox? how much does it cost to repair if it gets 'eaten'?
 

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Ok, so the DFP and EGR issues mentioned in this thread aren't much of an issue as they are cheep to repair. But, the DMF sounds iffy. Is that in the gearbox? how much does it cost to repair if it gets 'eaten'?
If it gets mashed, it'll cost a LOT of money comparatively, bargain on a replacement flywheel and clutch, along with fitting and occasionally they destroy the starter motor by filling it with swarf too.
 

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DPF is not that cheap to repair a garage would charge around 200 quid to remove and unblock it if its gummed,and if you dont use often enough in the right scenario it will just keep reblocking itself...


DMF and clutch ya looking at around 800-1000 quid (prolly more tho on the big BMW's) to replace and big heavy high torque diesels do eat DMF's again they get far more hammer from the torque if you dont use them on a motorway much, so longevity comes right down of the components on the drivetrain of which the DMF is one such component..

dont forget the heavier the car your trying to drag around with that high torque engine the more detrimental it is compared to the lighter cars...


EGR is to cool the bore temperatures to reduce NOx gas emissions which are deadly to anything with lungs as it turns to nitric acid on contact with moisture and dissolves things...
 

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Discussion Starter #27
Great clarification. Thanks.

I'm still thinking 6 or 7.

If a six series, there are a few 3 litre petrols out there. For a seven series, considering it will cost me at least £8,000 less to buy a used diesel, I can afford for the DMF to pack up and be replaced.

Decisions...
 

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there is a lot of variables here in your decision making rule 1 ya prolly not the best ideal candidate for a big diesel with your intended usage and you may or may not come a cropper depending on how long you keep it..


because of your low annual mileage tho you may make any classic diesel problems from your none motorway usage get further away though cos of the light usage all be it in an arena it does not like very much, but being as you are buying second hand this introduces another variable where you might just buy or may not buy somebody else's not ideal usage before you...so you then increase ya chances of grief with your future intended usage...


it's all variables and guesses but me being me i would always play safe and give myself the best chance of avoiding trouble by not buying summat that i intend to use in scenario it really dosent like that much in the first place...do you understand that as a basic rule of thumb type of statement? does it sound logical?

if you do then your eyes are open and you can make an informed or calculated choice on whats bin said i think...


and good luck in your quest:thumbsup
 

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Discussion Starter #29
Yup, all sounds logical. You've educated me here. Before I knew some of the disadvantages to buying a diesel if you only do 12,000 or so per year. Such as: diesel is more expensive than petrol, expensive glow-plug type things and the like. I worked out that you'd have to do 20,000 miles per year before it benefits. Not to mention all that rattly noise you have to tolerate. I wasn't aware of some of the other things you've mentioned though.

I've known two people who bought small diesel cars (one a Citroen, the other a Peugeot) because they thought they would save money. At the time, I said to them both: 'You only do 10k a year, it's not worth the extra price of diesel and the extra price of those components that pack up, which they will.' Both these girls sold a Vauxhall Corsa and a Ford Fiesta to buy these same year diesels. Within six months they were both complaining about expensive things that packed up. Oh, both were only doing short school type runs and round town stuff. Lady with the Peugeot had to spend £175 on, can't remember exact name for it, but a glow plug thing? not once, but four times during the first four months, £700. I figured if that was a petrol car it would have been four spark plugs at £3.00 each. Basically, that £700 killed any petrol saving for the next 20K, probably two years the way she drives, and that's if she had no more problems over that two years, which she did, big time. Both these girls did, big time. But, they persisted and kept on spraying the money hose at these stupid cars. Fact is, it was penny pinching. Going from a 1.3 fiesta petrol to a 1.6 Peugeot diesel was a stupid thing to do. Oh yes, the used diesel car she bought cost her £1,500 more after she trading in her petrol. Add that to the £700 and we were up to £2,200. Plus she had about £800 of other diesel related crap go wrong with the car, so about £3,000 in total. I figured she'd have to do 60,000 miles in that car just to break even. By then, the silly little engine and gear box would be about ready to give up the ghost anyway. Point is, I'm just telling you this little story to let you know that yes, it does sound logical to me, but then, I'm quite an intelligent guy. Also, one small thing, in the UK, the government could quiet possibly f••k us all in the a••s for owning a diesel if they decide to hit the 'city tax' thing with diesel owners in this country. So many reasons to have petrol. Shame there is so little choice though with a 7 series. But, if I keep my options open and go for a 6 or a 7, which ever comes up and looks like a deal first, I could be in.
 

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example my car 01 330 owned 12 years since it was just over 12 months old still on original drivetrain inc clutch and DMF everything and spent less than 300 quid on failed engine parts and drivetrain in 12 years and 144+k... if there is a diesel 330d out there of the same age that can match that expense without bullshitting ide be very surprised, most have had at least either clutch and DMF , injectors overhaul or a turbo by that time...because most of them fell into the hands of urban jungle warriors and such abuse after the 3 years of probable motorway and lease use ended on them...


should of had a newun years ago in truth i can afford it, but it keeps on plugging with minimal grief and has never broke down ever (touch wood) so i keep it and it's the last of the naturally aspirated big 6's so i can fix anything on it myself for buttons itsa simple engine with cheap components...it owes me nothing and still looks and drives like new...

navigating the minefield of the many abused and poorly treated diesels these days by definition with their current popularity is difficult and needs careful,logical thoughts and homework...
 

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Discussion Starter #31
Oh yes. I forgot. I actually bought a used 330d estate about three years ago. Wondered why there wasn't much power and was only doing 24mpg. Took it to independent specialist who told me the turbo had packed up and a recon one was going to be £900. At the time I was not familiar with diesels and I just assumed it sluggish because it was a diesel. I ended up getting my money back off the seller after threatening with court and standing on his doorstep being a little intimidating.
 

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Discussion Starter #32
Just thought of something, this DMF issue, from what I've read about them and what they do, basically:

DMF: Basically it's a flywheel in two concentric parts or two facing flywheels stuck together with flexible compound to damp down transmitted vibration from diesel engines, improve gearchange quality and protect transmissions from torque reaction at around 2,000rpm, particularly the change from first to second.

Now, with the above in mind, does this mean they are only found on manual cars? I'm thinking of buying an Automatic car so would the DMF issue with a diesel auto not exist as it would in a manual car?
 

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Discussion Starter #34
Great, so everything talked about so far in this thread with DMF issues with the BMW 7 series 3 litre diesel won't apply to me. 7 series it is then. Funny, I just assumed that everybody on here would know that the 7 series don't come in a manual, they only make an automatic in that series. So pleased that's sorted, my problems are over ;)
 

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i did mention earlier that bmw dont put manuals in the big diesel cars cos of the super destructive torque...i assumed you knrew DMF's were on manuals...big diesels do pummel auto transmissions but that was more an issue in the beginning mainly when BMW was using off the shelf transmission shit cos nobody made an autobox strong enough to handle a big diesel cos there were no big diesel domestic cars until year 2000...


DMF is just a giant rotating shock absorber that absorbs the torque pulses from the engine (diesels emit very high torque pulse)its the individual cylinder detonations and the shockwaves from that that travels down the conrod and on to the crank and along the drivetrain, undamped it would shake and batter the drivetrain to bits..auto's still get pummelled by it but being fluid they aborb it better, but again the intended usage is all important if you are going to avoid any potential trouble..motorway use =less destructive torque,urban use =more destructive torque...
 

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Discussion Starter #36
Thanks for clearing that up, dailydoggy. No, I didn't even know what a DMF was, let alone they only went in manuals. So, the Seven series would have the bigger/tougher auto box from about what year exactly? I'm assuming All F01/02 shape from 2005 would be ok?
 

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im not sure to be honest you would have to check via realoem.com wether the car in question has got a more robust box in it or not...

F01 and F02 are 2007 onwards arnt they ???


think they would have the ZF box designed jointly by ZF for BMW for big diesels outputting up to 600NM of peak torque...
 

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will be a ZF box...

if ya hell bent on one make sure you buy one thats bin up motorways or open roads prior to you owning it, DO NOT !!!buy an urban jungle used and abused example...
 
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