A V8 at last - my BMW 645Ci

[McSam]

I'm really starting to fall for this thing.

[Funk]

Git.

Glad you're enjoying it though!

[gf15]

Really pleased to see you are getting on with it. They are a very under rated machine. The real trouble starts when you start thinking of what you could replace it with for sensible money and come up with a blank. Yours is a fantastic colour and looks superb. Mine started to use a small amount of water (think a half a cup a month). There is a temp sensor on the driver side on the lower water pipe as it enters the radiator. It is a known weak point. Sensor is about £25 from BMW and a 5 minute fix.
Enjoy!

[minimatan]

Hi Sam,

I hadn't realised that there was a 'Reader Cars' forum on here and have been catching up with your purchase with interest, as of last night!

My 645Ci was purchase in February last year, albeit in splendid form in comparison to yours with a full BMW history. The Mondial warranty has sorted loads on bits and bobs out too. It is a very handsome car that has the same wheels as your winter alloys. I can live with the crashiness of the RFTs as they give good feedback and save any potential faffing around should a puncture occur. I have experienced a puncture before, twice. The second time, it didn't affect the handling (in an urban environment) despite having lost 6 PSI!

Your car is a nice combo of colours, though the wood veneer isn't to my preference. The Pano sunroof is an absolute must too as the ambience that it creates in the cabin is fantastic. I didn't really ever like the ellipsoids, but after seeing your side by side picture of the car, I really had second thoughts - though the 650i 19in wheels wins!

I may even start up my own readers car thread retrospectively!

Michael

[McSam]

Funk said:

Git.

Glad you're enjoying it though!

It does seem to attract that response from people who see it cheers.

Thanks again, GF. Occasionally I wonder "should I have waited for the perfect 650i", but then I remember you aren't selling, I'd have paid near twice as much and there aren't any in this colour!

Hi Michael! Your car sounds lovely, definitely deserving of its own thread. Mine is very much a rescue case in comparison, though I've always liked improving cars as I go along. The wheels are a bit of a dilemma for me at the moment.. I really am in love with the Style 218 19"s from the 650i, and I have seen some for sale, but after I got my ellipsoids off and felt how much nicer the car drove I swore it'd never have 19s again. A voice in the back of my head tells me it could just be the Bridgestones that were the problem, and with a decent tyre on the 19s might be fine.. the sensible side can silence it again by reminding it that the 275-section rear is unnecessary, crap in the wet and dire for fuel economy. But I still keep going around the circle..

If I could find an 18" wheel that I really liked, or indeed an 18" version of the Style 218, I'd be a happy man. Until then, style continues to argue with good sense!

[Funk]

I should not have watched those 645Ci with fruity exhaust videos.

DAMMIT. It might take a while but I think this is my next car. I have some reading to do.

[Granfondo]

That's mine on 18's and have 19's ellipsoids as well!

[McSam]

Funk said:

I should not have watched those 645Ci with fruity exhaust videos.

DAMMIT. It might take a while but I think this is my next car. I have some reading to do.

Heh, that was a bit of an influence on me too. The car does sound good from inside, and at very high revs it actually sounds pretty racy, there's a real hard edge to it which is lovely. It is, however, too quiet at full load. There are options aplenty, with several resonators you could delete and a variety of X-pipe systems out there. This captures the standard exterior sound quite accurately and shows what can be done:

https://youtu.be/lPpWE2o4BFc

Really it wants a switchable system, perhaps tied to the sport button. The volume at part load and cruising speeds is spot on and I wouldn't want to knacker that.

Granfondo, those wheels are an interesting choice, a more modern design but I think they suit it reasonably well.. I always resist going away from period OEM stuff but those are a possibility. Might mock those up onto one of my side profile shots. Your car is looking lovely ad ever!

[Granfondo]

The twin spokes are from 2005 so they are period!

[Funk]

McSam said:

Heh, that was a bit of an influence on me too. The car does sound good from inside, and at very high revs it actually sounds pretty racy, there's a real hard edge to it which is lovely. It is, however, too quiet at full load. There are options aplenty, with several resonators you could delete and a variety of X-pipe systems out there. This captures the standard exterior sound quite accurately and shows what can be done:

https://youtu.be/lPpWE2o4BFc

Really it wants a switchable system, perhaps tied to the sport button. The volume at part load and cruising speeds is spot on and I wouldn't want to knacker that.

Granfondo, those wheels are an interesting choice, a more modern design but I think they suit it reasonably well.. I always resist going away from period OEM stuff but those are a possibility. Might mock those up onto one of my side profile shots. Your car is looking lovely ad ever!

I like 'em a bit more growly:

https://www.youtube.com/watch?v=TpRjEWu8wjs (ignore the M6 badge wker)

https://youtu.be/bpISXiy2Z1s?t=40 (and again)

https://www.youtube.com/watch?v=Dac1QXRbj0w

Edited by Funk on Tuesday 16th February 01:47

[unsprung]

McSam said:

Beautiful machine, OP.

[McSam]

Funk said:

I like 'em a bit more growly:

https://www.youtube.com/watch?v=TpRjEWu8wjs (ignore the M6 badge wker)

https://youtu.be/bpISXiy2Z1s?t=40 (and again)

https://www.youtube.com/watch?v=Dac1QXRbj0w

Damn, you're an expensive guy to talk to, all of those sound rather lovely. Not sure which my favourite is yet. I think one that cracks on a full-throttle upshift is mandatory, because otherwise you can hear the slur as the torque converter slips down between gears. Again, I stress some switchable function is needed

Thank you, unsprung

[NDA]

In the Morgan the engine exhaust sounds quite fruity:

https://youtu.be/SiFg4JLG9pk

[McSam]

It's a lot easier when a side-exit exhaust is acceptable! The same character is there in the 645Ci and 650i, just a lot more muted.

On a vaguely related note, I've been out with the Autosol today. My tailpipe finishers were looking decidedly past their best..



But a bit of elbow grease has brought them back nicely:







Oh, almost forgot, I was messing about with diagnostics earlier and I was curious to see how the engine load varies between idling in neutral and D. So here you go, from a warm idle..

Neutral:



Immediately after selecting D:



Five seconds on the brakes after selecting D:



This is quite interesting. The bits we're concerned with are the air mass flow and the "% DK", which stands for Drosselklappe - throttle. There is some fluctuation in the MAF numbers but the ones shown above aren't far off the average.

So in neutral, we have 2% throttle and 14kg/hr, which equates to around 1.3 litres of fuel per hour (stoichiometric ratio is 15:1 and a litre weighs 0.71kg). As soon as you select D, the throttle opens to 3% and we're at 23kg/hr (2.2l/hr) ready to pull away. But if you hold the brakes, over the next five seconds the load drops away smoothly until it settles at around 2.3% throttle and 16kg/hr (1.5l/hr).

So there is at least some aspect of disengaging the torque converter clutches when stationary at idle, it's just very hard to perceive because it's a smooth ramp-out rather than a step change. Now I've seen this behaviour, it explains why there can be some hesitation pulling away when you've been stationary for a few seconds - the clutches need time to re-engage. In any case, it means you're only using around 15% more fuel to let it idle in D when stationary for long periods. Not too bad, nor is the idle consumption as a whole.

In case you were wondering - and still awake - the highest I saw out on my test run was 860kg/hr at peak power. So you'd get a fuel range of 52 minutes if running flat out!

Edited by McSam on Saturday 27th February 18:18

[McSam]

After a rather sizeable bill from Autotech of Warwick, I now have a much happier N62. Cam cover gaskets were diagnosed as the cause of the oil leaks, both banks needed doing, and I asked them to do the upper timing case gaskets while they were in there - you'd need to do nearly as much work again if they later failed. I took a bit of a punt on what could be causing the coolant leak - the supply pipe running through the middle of the V is known for failing and, again, an enormous amount of work to get to on its own but not much more effort if you already have the intake manifold and cam covers off, so I asked them to do this.

Now I've been running the car for two weeks and have had absolutely no coolant consumption, no dodgy starts or misfiring, no oil leaks that I can see and a generally far more pleasant experience! I'll pop it back on the ramps this week to double-check for any more oil leaks, but all seems well so far.

This is good, because it's about time to spend money in another direction, summer tyres. I like the car so much on its 18" Style 118s that I'm going to use them for summer too, so I'm thinking of buying a set of Goodyear's new F1 Asymmetric 3s for it.

This means that the 19" Style 121s that the car came with are redundant, so they're now up for sale. Drop me a PM if you'd be interested, and while I can't advertise them here per se, if you were to search your favourite online auction site for a 'set of genuine BMW Style 121 19" alloy wheels & Bridgestone tyres', you'd probably find them...

[parabolica]

Out of interest, how much did all that work cost you (roughly)? My 645 has similar issues and currently threatening to fail its MOT due to emissions/engine issues. Reckon I'm going to have the same issues as you. Currently weighing up whether to get the work done and cherish the car or cut loose. Current quote from my local Indy is £5k+ open ended!!

[McSam]

That seems a bit excessive! I made the decision to keep long term and cherish the car before getting this work done, not that I had a lot of choice as I wouldn't have been comfortable selling it on with the issues, but it certainly isn't in that league. Breakdown as follows, all inc VAT:

• Cam cover & upper timing case gaskets replace, both banks: £629.78 (parts £200.78, labour £429)
• Intake manifold gasket replace, both banks: £58.22 (parts only, found to be degraded during above)
• Vacuum hose replace: £44.95 (parts only, found to be degraded during above)
• Oil flush, refill and filter replace: £117.60 (fluids and parts only)
• Coolant vent pipe replace: £211.70 (£148.50 labour, £63.20 parts and coolant)
• Air con regas: £36.00 (discharged to move a pipe for access, found to be near empty so recharged)

Total: £1098.26

The first of those includes a new oil pressure switch and various fixings that shouldn't be used again. The cam cover gasket kits were £78/bank and the timing case gaskets £6.68/bank.

What symptoms does your car have? I'd expect that going in with a mandate of "investigate and fix all you find" could easily generate scary estimates like you've said, but when you can find specific faults.. they're really not too bad to work on. Unless you needed the heads off, there isn't much you couldn't get done in the labour I've paid for above.

[parabolica]

There is an oil leak somewhere in the engine; to begin with symptoms was blue smoke upon heavy acceleration when the engine is hot/been sitting idle for a few minutes (I,e, at lights). Now it seems to be a fairly constant blue smoke during normal acceleration. My first thought was Vlave Stem Oil Seals as they're a known problem, but it could be any seal really! Will see what the next week holds; I'm slightly more hopeful now hearing your breakdown of the costs!

[Funk]

I'm slightly more anxious hearing the breakdown of costs...!

Still got my eye on one of these down the line although I've also added the 650i to the list. Sam, it seems you're pretty handy with the spanners whereas I'd have to pay a man to do everything mine needed... Looks like I'll need a float handy at all times if I do take the plunge.

[McSam]

parabolica said:

There is an oil leak somewhere in the engine; to begin with symptoms was blue smoke upon heavy acceleration when the engine is hot/been sitting idle for a few minutes (I,e, at lights). Now it seems to be a fairly constant blue smoke during normal acceleration. My first thought was Vlave Stem Oil Seals as they're a known problem, but it could be any seal really! Will see what the next week holds; I'm slightly more hopeful now hearing your breakdown of the costs!

Ah, I'd forgotten about the valve stem seal issue. That one really can run up towards the numbers you mentioned, just due to the sheer time involved in replacing all 32 stem seals.. it's amazingly labour-intensive. The smoke from a hot idle can be due to the rubber diaphragms on the CCV (crank case vent) valves failing. Admittedly I've never heard of this causing smoke under constant load, but it could be worth a look anyway - the below is a pretty nice guide on how to check them. So long as you're gentle, no mechanical skills required!

https://www.youtube.com/watch?v=FBy0tRn2xLw

Funk said:

I'm slightly more anxious hearing the breakdown of costs...!

Still got my eye on one of these down the line although I've also added the 650i to the list. Sam, it seems you're pretty handy with the spanners whereas I'd have to pay a man to do everything mine needed... Looks like I'll need a float handy at all times if I do take the plunge.

Heh, well this is the biggest bill I plan on paying, but at five months and around 4,000 miles it's too early to say whether it's representative of ownership yet. If you can get yourself a 650i I definitely would, I think they'll hold their value rather better, they're more efficient as well as being more powerful, and there is a nice fuzzy feeling to the fastest non-M car bar none! I wouldn't compromise on spec to get the later engine, though, hence my decision with this one.

The cam cover gaskets were just past the limit of what I'm prepared to do. I looked at the rather good DIYs that have been posted, and it scored a 9 on the ballache/potential downtime/risk of finding or causing other broken parts scale - 8 is my ceiling on a car I'm using every day I think I made the right decision, as a few other bits were spotted and replaced far more efficiently than I could have done. It's also very possible to damage the eccentric shaft sensors while removing the cam covers, which are likely caked on firmly after 120,000 miles, another prospect I didn't relish. Probably says a lot that the owner of Autotech did this job himself - think he's been working on BMWs over 20 years now.

If I had one piece of advice for prospective buyers (other than obviously researching all the common faults to death because they really are common), it would be to get the car on a ramp and take the undercovers off for a proper look before you buy. Mine looked absolutely fine viewed on the ground, but was hiding a huge and clearly long-term oil leak that you'd never have missed with a proper inspection.