Looking for a G31

[Greenfingers]

Hi guys, I'm an old member from the F section of these forums.

After 6 years of ownership, my F07 is still in fine fettle at 136k miles, but I'm itching for a change. She's the best all round car I've ever had out of a good variety of vehicles over the years, so finding a suitable replacement is proving to be a challenge. A couple of years ago, I put a £100 deposit down for a new Tesla Cybertruck, but production of that keeps getting delayed and we probably won't be seeing them on UK roads for another couple of years, so now I'm looking for something to bridge the gap.

With 3 kids, I still occasionally need 5 seats, which rules out a full on sports car, but I do like a bit of grunt from the loud pedal. The N57 provides a nice blend of smoothness, power and econony. I do almost all the maintenance myself and having owned a number of 6 cylinder BMWs, I'm fairly well adapted to dealing with their nuances, so the logical step would be to move on to something with a B57 engine and the G31 is big enough inside. However, there are a few things that concern me about Euro 6 compliant diesels and it would be great to hear owner's opinions.

Some points to consider:-

Is the Adblue system likely to give significant trouble on a car with over 100k miles on the clock and does it really reduce efficiency?

Do the tighter Euro 6 constraints put more stress on components (EGR, DPF, turbo etc)?

It is easy to remap the N57 for more bhp and better ecomony and also prevent the EGR valve from opening, resulting in no more soot deposits. I understand it is an offence to drive a car with parts of the emissions system disabled, but in reality is it viable to disable Adblue instead of fixing it if it breaks?

In a similar vein, I've heard that for stop/start systems to actually reduce emissions, you need to be stationary for at least 30 seconds. When I drive my wife's F31, it seems the engine is mostly shutting down for much less time than that, which must also be bad for the battery. In the F31, start/stop can be turned off - is this so in the G31?

Reportedly, these newer models are much more refined to drive than their older counterparts; do you agree and have you found other things that are improved or worse?

Any pointers would be greatly appreciated and I'll probably be coming back with more questions over the coming days.

 

 

 

 

[BobA]

I do low mileage so can’t comment on a lot of the points.

You can turn the stop-start off but as standard it always comes back on when you restart the car. But you can code it so that it remembers what setting you left it on. So if you turn it off and don’t touch it it then stays like that (what I’ve done). It’s always on in ECO though.

The (diesel) G is a quieter drive than my F was but I’d say there’s not much in it for handling and thumping over potholes etc.

I’ve had no issues in 4 years (but lowish miles) except the emergency call battery dying recently.

FWIW I find the touring is quite awkward to reverse into slots even with the camera, maybe just me. The icon lights aren’t xenon’s but they’re good. The xDrive sticks to the road well.

Edited January 7, 2023 by BobA

[ally]

I wasn’t an F10/11owner but did drive a couple as hire cars. 
The G30/31 is a more refined experience, no doubt about that. 
ID6 is excellent to use, I like pretty much everything more about the interior apart from a couple of wee things, first being the instrument cluster itself. 
In comfort mode, I would prefer to see all white dials during the day and all orange at night, which also matches the rest of the controls, like previous cars. 
I understand that it looks different anyway, when using sport mode and eco, but I rarely use those. 
I did also prefer the centre screen where it was on the F series, under the dash rather than stuck on top. 
The seats are better, even the ID controller is better in that at is now a bit easier to access and use, as opposed to when it was sloped forward / down the way in the F series, which I think has improved the ergonomics there. 

My car is pre LCI, can’t say I am a fan of the LCI instrument cluster either, but that’s the way they are going, so might be one of those things that grows on you. 
I can’t imagine how Adblue can reduce efficiency, given where it is introduced into the system, but I’m happy to be corrected on that. 
EGR valves are a real problem on diesels though, mines stuck open and I couldn’t get it to work properly after removing and cleaning, so I replaced it myself, (ISTA is very advisable for this, otherwise you risk damaging the new EGR valve upon installation) 

Intake manifolds become very gunked up too, I get the idea behind the EGR systems, but in reality they are poor. 
 

[Greenfingers]

Thank you both for those thoughts. Oxford Council seem to be more anti car than most and are among the first to impose zero emission zones. I don't want to risk being barred from my home town in a Euro 5 car, so it seems Euro 6 is a must. I believe that Euro 6 compliance for a diesel requires more intensified use of the EGR system, with even more detriment to the longevity of components and the guy who tuned my GT suggested that swirl flaps are now a bigger problem with Euro 6 cars, due to the extra soot being recycled. Ally, is it possible your gunk was contributed to by short journeys?

In any case, I'm looking at entry level prices for a G31 with 6 cylinders, which will mean something with high mileage. One that ticks most boxes for me is on Autotrader:-

https://www.autotrader.co.uk/car-details/202210311245591?fromSavedAds=true&advertising-location=at_cars

I'm not too bothered about toys, but would prefer sports seats and that ivory leather looks like it won't wear well.

Another option is an ex Police car. I bought a high mileage ambulance last year and converted it into a camper van - it drives beautifully, which is testament to that stringent maintenance schedule. The Police cars I'm looking at have done around 100k miles, but with around 10k service intervals are probably in good mechanical nick. White is not great IMO and they all have battle scars, but at least I wouldn't feel the need to park in the most remote spot at Tescos! Leather interiors can be had for under a grand on eBay and I quite enjoy a project. One thing I'm not sure about is the viability of upgrading the CID spec 8.8" screen to a high def 10.25" - Matthew would know 🧐

[ally]

Yeh, short journeys aren’t good but unavoidable at times. 
My car does see some longer journeys more regularly these days, which should help with some things. 

[Procion]

I ran my G31 530dX for 15 months and put 20K miles on it. It proved reliable during that time doing a split of 50-50 motorway & town. The 2 problems it threw up were 1) the air compressor for the rear suspension chafed a wire thru and stopped working. 2) The DPF failed and was replaced under warranty.

Got used as a shed on many occasions carrying several hundred kg a time in the back. It was M sport spec, and I hated the seats as they gave me back ache. Awkward to reverse with mediocre rear visibility and no camera. Also, it would adopt a strange turning line when going backwards, or so it seemed to me.

Averaged 30/35 round town, 40/50 on M.way. Low profile RFT tyres (Michelin Premacy 3s) 275/35/19 + 245/40/19 made for a rubbery feeling ride but quiet, hard wearing and grippy in all conditions. Had “normal” headlamps which were way better than the candles of my E61, HK sound system was good and a few extra toys to play with.

Brakes excellent and still on original pads and rotors when I sold it.

Only topped the AD Blue up 3 times whilst I had it, ran it on V power diesel always and changed oil every 10K. Reasonably quick but no fireball so not very exciting in that department, excellent handling and grip when pressed. Generally, a laid-back demeanour to the car, with good ride even on crap roads. The G31 chassis is superb (try it out with the ESP off) its pedigree shines through even on poverty spec 520s.

Versatile car did everything I asked of it without complaint. Would I buy the same? No, I’d go 540i.

As a footnote and I’m speculating here, I would of thought high quality fuel always, frequent long runs and the odd Italian tune up would keep any soot & crap under control? Never saw a flake of soot on the exhaust tips of mine but obviously don’t know about EGR etc.

Think you'd be wasting your money remapping it or adding a generic tuning box. To what end / why bother? You seem concerned about reliability so why stress stuff by trying to get it to do something it wasn't designed for? Most remaps I've seen just ram more fuel in and are pretty poor. Proper mapping needs to be done on a rolling road and adjusted to suit the unique characteristics of your engine.

Edited January 8, 2023 by Procion

[Greenfingers]

Surprising to hear you didn't like the seats Procion and yes, petrol is probably the best bet for a Euro 6 car, although I'm too tight fisted to pay for a 540i.

On Monday I went to see a batch of 530d Xdrive police cars that were coming up for auction. They were all a bit shabby, but that was expected and I would probably swap out the interior anyway if I bought one. The screens had been removed, so it was impossible to check anything on the idrive, but I have learnt that the Police vehicles are supplied with a really poor spec:- no sat nav, leather, heated seats, folding mirrors or lots of the things we take for granted.

The mileages ranged from 85k to 140k and all engines sounded sweet. All cars had Goodyear Excellence tyres with loads of tread and brakes in good nick. Each one had a service printout detailing every visit to the police workshop and I asked to see the printout for my preferred car. The list was 5 pages long and specified codes that I didn't understand for many of the items, but it was clear to see that the car had been in numerous accidents and had multiple wheels and tyres replaced. It is astonishing how much maintainance is done:- well over 50 visits during a 5 year service life. At least it was reassuring to see that the oil had been changed at maximum 10k intervals, but boy those cars have a hard life! I was ready to place a lowly bid at the auction, allowing £2-3,000 for remedial work, but the car predictably sold for about £1,000 over that.

I phoned the dealer who is selling the car in the link I posted to ask about it's history. Suffice to say, he had no idea what the 'full main dealer service history' comprised - just that it showed up on the idrive. The Gov.uk MOT checker showed all 4 tyres as advisories on the previous MOT and he couldn't even confirm whether they had been replaced. I didn't tell him that the car was currently under recall and instead asked him for the VIN, which he gave me and today I went to my local BMW dealership, who were happy to tell me the basic service history and that the recall is for reprogramming the egr system. The car is over 3 hours from me and I am wondering if it's worth spending £100 and wasting a day to discover it needs new tyres, brake discs and front suspension when the seller can't be bothered to tell me.

I don't need a new car, so probably best wait until something grabs me convincingly. I've also been pondering over getting a Merc CLS estate, but don't relish stripping half that V6 engine down to clean the manifolds and fix the inevitable oil leaks.

[ally]

The right one will come along. 
 

[NuggetsG31]

On 08/01/2023 at 16:13, Greenfingers said:

Thank you both for those thoughts. Oxford Council seem to be more anti car than most and are among the first to impose zero emission zones. I don't want to risk being barred from my home town in a Euro 5 car, so it seems Euro 6 is a must. I believe that Euro 6 compliance for a diesel requires more intensified use of the EGR system, with even more detriment to the longevity of components and the guy who tuned my GT suggested that swirl flaps are now a bigger problem with Euro 6 cars, due to the extra soot being recycled. Ally, is it possible your gunk was contributed to by short journeys?

In any case, I'm looking at entry level prices for a G31 with 6 cylinders, which will mean something with high mileage. One that ticks most boxes for me is on Autotrader:-

https://www.autotrader.co.uk/car-details/202210311245591?fromSavedAds=true&advertising-location=at_cars

I'm not too bothered about toys, but would prefer sports seats and that ivory leather looks like it won't wear well.

Another option is an ex Police car. I bought a high mileage ambulance last year and converted it into a camper van - it drives beautifully, which is testament to that stringent maintenance schedule. The Police cars I'm looking at have done around 100k miles, but with around 10k service intervals are probably in good mechanical nick. White is not great IMO and they all have battle scars, but at least I wouldn't feel the need to park in the most remote spot at Tescos! Leather interiors can be had for under a grand on eBay and I quite enjoy a project. One thing I'm not sure about is the viability of upgrading the CID spec 8.8" screen to a high def 10.25" - Matthew would know 🧐

I've owned my 2018 530D MSport pre-LCI for 4 years now and put almost 87,000 miles on it. It hasn't missed a beat.  I had a couple of issues, one with the passenger side mirror (known issue when reversing) and the lower active flap failing, both sorted at no cost. 

Before the G31 I had an E90 (320D MSport) and an F32 (435i MSport).  My father inherited the E90 at 183,000 miles, it's now done 285,000 miles, with a bit of preventative maintenance (and luck) a BMW diesel will go on and on.  I used it the other day whilst BMW had my car for EGR software and it had forgotten how hard, twitchy and generally uncomfortable the E90 with sports suspension is, "agricultural" is probably the best description.  

After my E90 and F32, both which had harsh "crashy" rides, I opted for comfort seats (456) and the adaptative drive (2VA) and it is a very refined ride, even on 19" run flats.  Living in Cambridgeshire, the roads here could be mistaken for the surface of the moon and I did suffer a cracked alloy and buckled other one, but I think this could happen in any car with run-flats so you take your chances.

Adblue is introduced to the product of combustion using an injector in the exhaust to convert NOx to nitrogen, water and carbon dioxide so I can't see how it reduces efficiency when it doesn't play a part in the combustion cycle.  I've never had a problem with the Adblue system, I've always filled it up with known brand quality ad-blue and typically keep it topped up to stop too much air in the reservoir.  

IMO fuel quality doesn't matter so much for diesel, as unlike petrol, diesel doesn't have different octane. B7 is all produced to the same Standard (EN590), premium diesel supposedly has detergents added but I'm a sceptic myself I tried a tank full once and the only difference I noticed was I was even poorer after filling up.

So far I have not had an issue with EGR or manifold soot build up I think perhaps a driving style helps here, I did cover a lot of motorway miles the first three years of life, always used BMW spec oil and never ever delayed an oil change (true for any diesel I have owned) and 99% of runs had the engine up to temp and running at operating temperature for a while.

I think short journeys are a killer for any diesel, let a lone a big 6 and what is true for any diesel is that you need to get heat into the engine each trip for the EGR system to do it's thing properly.

When I get to the next major service at around 100k miles, I will take it to my specialist independent and get them to change the ZF auto gearbox oil and filter, for the cost I think it's well worth doing even though it's not a manufacturers service item. 

Regarding ex-police cars, my cousin used to work for the Met Police in the garages, depending on force an ex-police car should be serviced to death, and serviced competently with it. I do doubt they will have changed the gearbox oil (and filter if an auto) as it's not in scope of manufacturers service.

Overall G31 diesel is a solid car, very good chassis and will eat the miles. The diesel engine is very torquey and pulls away from most things when already rolling, it returns 42mpg on a steady motorway cruise at 80mph.   

If I had my time again, I would buy the same spec, but I think I would go for the 540i, simply because I miss the sound of a big petrol engine. When I had the F32 (435i) with the BMW sports exhaust, the sound was glorious.

I would agree with Procion about avoiding remaps and plug in boxes, you have more to lose than gain as all the plug in loom boxes do is trick the fuel system into boosting the rail pressure and delivering more diesel at lower rpm, this means more diesel combustion products in your engine oil which will lower its longevity and lead to sludging and soot build up more quickly.

If you are concerned about swirl flaps sooting you could get a B57 delete kit and code the flaps out, but be prepared for a drop in performance. 

IMO it is probably better to buy yourself a cheap ultrasonic bath then strip, clean and reassemble the EGR and inlet manifold and it probably won't ever be an issue for the time you have the car, maybe consider getting a walnut blast done on the block inlets if they are badly sooted too.

 

[Stressed]

Ex police/emergency service vehicles are well maintained and serviced. BUT don't forget they are driven by different drivers every shift and driven VERY VERY hard. (no slowing for speed humps etc)

Think carefully, as a blue light driver you can in theory thrash the living daylights out of the vehicle and not give a dam because it's not yours you don't pay for it and it's just there to be driven to do a job! Also get an emergency call when it's cold with a cold engine it's full throttle with no warm up time at all!

After 30 years in the emergency services 17 of them as a blue light driver before promotion would I buy one. NO NO NO

Edited January 13, 2023 by Stressed

[Greenfingers]

There seems to be a general consensus that the B57 engine is better than the N57, which in turn evolved from the M57 and for sure, development and modern technology have improved efficiency. However, the bulk of changes have been forced by ever increasing emissions constraints, for the good of the environment but to the detriment of performance. When M57(Euro 4) engine swirl flaps started failing, they were beefed up a few years into the production cycle. Swirl flaps in the N57 were less notorious, but that engine had to conform to Euro 5 NO2 emissions (down further from .25g/km to .18g/km), which I believe intensified the use of EGR, resulting in more carbon deposits and overall wear. Euro 6 brought NO2 right down to .08g/km, meaning even more stress for the engine.

So can these new diesel engines be as durable and reliable as the previous generation? Firstly, they all need to use SCR, which sounds like an unreliable system in all makes of car, but what effect is all that reingested soot going to have? Looking on Autotrader, there are only a handful of B57 engined BMWs that have done over 100k miles and I wonder if we are going to start seeing major failures before long. For a start, swirl flaps seem to be a big problem again: this shocking video is in Russian, but you will get the idea from the pictures:-

 

Edited January 15, 2023 by Greenfingers
Typos

[Greenfingers]

Not sure if it was a wise move, but I am now the owner of an ex-Avon and Somerset Constabulary 530dX Touring!

The good news:- just 70k miles on the clock and a fully documented print out showing 11 oil changes, nearly new 18" high profile Goodyear tyres all round, surprisingly straight bodywork with hardly any dings and it was much cheaper than a civvy equivalent.

The bad news:- plenty of paintwork chips to sort out and it's well below poverty spec with a fair few components missing inside.

My pal who brought it home says it drives faultlessly, but I haven't had a proper yet: I was planning to keep using the F07 while stripping out and refitting the G31 interior, but am now deliberating about what to do. Used leather interiors seem to be available for under £1k on eBay, but this cloth interior is actually in pretty good condition - bar a broken plastic trim on the drivers seat and the seats are comfortable enough with lumbar adjustment, so I'm not sure if replacing them is worth the expense and trouble.

The main thing I need to address now is the ICE:- the idrive head unit (8705952 head unit for basic media 2) has no GPS or DAB functionality. Also, the display screen had been removed from it's casing and relocated in the centre armrest unit, so I have nothing to fill the void where the screen should be. I could just get a replacement 8.8" factory display, but that would provide scarce functionality and not look great either. An upgraded, used OEM head unit with GPS, DAB and a bigger touchscreen would require coding, cables etc, which is going to be costly and time consuming. My inclination is to buy a Chinese aftermarket touchscreen unit with Carplay and Android functionality; I believe these tend to be plug and play and include GPS, wired USB ports (mine are missing) and optional reverse and dash cameras. It's difficult to find good objective reviews on these, so I'd love to hear from anyone who can advise.

 

[Liam2594]

On 10/02/2023 at 11:57, Greenfingers said:

Not sure if it was a wise move, but I am now the owner of an ex-Avon and Somerset Constabulary 530dX Touring!

The good news:- just 70k miles on the clock and a fully documented print out showing 11 oil changes, nearly new 18" high profile Goodyear tyres all round, surprisingly straight bodywork with hardly any dings and it was much cheaper than a civvy equivalent.

The bad news:- plenty of paintwork chips to sort out and it's well below poverty spec with a fair few components missing inside.

My pal who brought it home says it drives faultlessly, but I haven't had a proper yet: I was planning to keep using the F07 while stripping out and refitting the G31 interior, but am now deliberating about what to do. Used leather interiors seem to be available for under £1k on eBay, but this cloth interior is actually in pretty good condition - bar a broken plastic trim on the drivers seat and the seats are comfortable enough with lumbar adjustment, so I'm not sure if replacing them is worth the expense and trouble.

The main thing I need to address now is the ICE:- the idrive head unit (8705952 head unit for basic media 2) has no GPS or DAB functionality. Also, the display screen had been removed from it's casing and relocated in the centre armrest unit, so I have nothing to fill the void where the screen should be. I could just get a replacement 8.8" factory display, but that would provide scarce functionality and not look great either. An upgraded, used OEM head unit with GPS, DAB and a bigger touchscreen would require coding, cables etc, which is going to be costly and time consuming. My inclination is to buy a Chinese aftermarket touchscreen unit with Carplay and Android functionality; I believe these tend to be plug and play and include GPS, wired USB ports (mine are missing) and optional reverse and dash cameras. It's difficult to find good objective reviews on these, so I'd love to hear from anyone who can advise.

 

I had one of the aftermarket units in a previous F10, functionality was ok and had a fair few bits on there. Mine had the reverse camera too which was not bad quality. In fairness I removed it all and put back the standard stuff (personally I'm not a fan of non-standard items), however if yours is going to need loads of additions to get a standard unit to work I'd most definitely consider one of the aftermarket units as an option.