W216 2007 CL600 - V12 engine specialist

[Sunny P]

Hi All,

Am new to the forum and hoping for some guidance.

I have a 2007 CL600, and have had it for around 8 years now. It has done around 135k, and overall, it has been a joy to drive. It has had every routine service done by MB in and around London. I’ve had many of the common problems on it during my time of owning it, including hydraulic suspension struts (twice), replacement coil packs previously, voltage transformer a few years back, Transmission ECU and various window modules, etc. for a car that cost (someone else!) £115k new, I am shocked by how unreliable it can be!

I recently had plugs changed on major service (by MB Beaconsfield). Unfortunately, when they were reassembling the car they didn’t secure one of the coil packs properly, and it ended up misfiring within a few miles of picking it up. I took it back (pointing out what they had done) and they’ll it turned out that one of the coil packs had been damaged by their error. They were good enough to replace it (for free - at what would otherwise be circa £1500 including labour).

Having had it for a few months since the above events, it now seems to drive well for a few minutes (eg 10 or so) when cold, and then starts to misfire. It produces a very low rumble after this, and has very little power. It’s so low that it is not possible to drive up any sort of incline without dropping manually into low gears.

I’ve connected up a fairly basic obd scanner, and it suggests that there are misfires on cylinders 7-12. It also flags up faults with camshaft hall sensor, as well as an o2 sensor that was only recently replaced (on the side with the new coil pack).

I’ve read various threads about different possibilities, but don’t want to get into changing the other coil pack or VT. I’ve also lost faith in MB a bit, and am loathe to giving them more money for them to persuade me to buy another coil pack.

Is anyone able to offer some ideas on possible causes?

Are you able to recommend any good independent specialists that know the MB V12 engines reasonably well? Ideally, I’d want someone in the Buckinghamshire / NW London area, but I don’t mind travelling a bit.

Any help anyone can offer will be appreciated.

Thanks,

Sunny

 

[Richard Moakes]

I guess I have a suspicious mind, but are you sure they replaced the damaged coilpack?

 

[Sunny P]

I guess I have a suspicious mind, but are you sure they replaced the damaged coilpack?

Thanks for replying. And I think it’s a fair question.

Yes - definitely. I replaced the previous one, and now can see the new one (with a 2023 manufacture date on the coil pack). It looks brand new and very clean! They’ve definitely replaced that side.

Forgot to state on my post (but I’m sure it’s obvious) that the engine management light is permanently on on the dashboard. Even after deleting the code it reappears instantly after restarting the engine.

 

[AMGeed]

Terry at Wayne Gates in Harrow NW London comes highly recommended by those who have used him.

Wayne Gates Specializing in Mercedes-Benz Servicing & Repairs

The Independent Merc Specialist you can trust. Based in Harrow, Middlesex servicing the surrounding areas and Hertfordshire. Call now to book

www.mercservicing.co.uk

 

[Richard Moakes]

It would be useful if someone local to you has Xentry/DAS to give it a good diagnosis.

If I ever get brave enough to go for the v12, I always promised myself that I would get the full package from https://www.v12icpack.com and assure myself the issue with coils and amplifiers was sorted once and for all.

 

[LostKiwi]

Cylinders 7-12 are all the same bank.
You don't say if that's the same pack they changed.

 

[Sunny P]

Cylinders 7-12 are all the same bank.
You don't say if that's the same pack they changed.

I’m fairly sure it is that side that was changed - the new coil pack is on passenger side of the car (UK RHD), part no 2751500780. I believe that cylinders 1-6 are on the driver side, and 7-12 on passenger side. If I am right about that, the fault is on the side with the new coil pack.

 

[Sunny P]

It would be useful if someone local to you has Xentry/DAS to give it a good diagnosis.

If I ever get brave enough to go for the v12, I always promised myself that I would get the full package from https://www.v12icpack.com and assure myself the issue with coils and amplifiers was sorted once and for all.

MB fitted a new Voltage Transformer Unit in late 2018, at a cost of around £750. I hope that hasn’t gone again too! I know they get very hot as they are on top of the engine (what a silly place to position it).
The V12icpack guy seems to know his stuff. Are there any British or European firms that do the same service? There’s a Dutch company (ABC Specialist) that seem to do it, but I don’t think they use uprated components like the American. Also, they aren’t my favourite company as the remanufactured ABC hydraulic suspension strut they supplied me failed just over 2 years after purchase, and so I wasn’t able to get them to do anything about that.

Perhaps there’s a gap in the market for it in the UK??

 

[peterws1957]

MB fitted a new Voltage Transformer Unit in late 2018, at a cost of around £750. I hope that hasn’t gone again too! I know they get very hot as they are on top of the engine (what a silly place to position it).
The V12icpack guy seems to know his stuff. Are there any British or European firms that do the same service? There’s a Dutch company (ABC Specialist) that seem to do it, but I don’t think they use uprated components like the American. Also, they aren’t my favourite company as the remanufactured ABC hydraulic suspension strut they supplied me failed just over 2 years after purchase, and so I wasn’t able to get them to do anything about that.

Perhaps there’s a gap in the market for it in the UK??

I looked into this when a coil pack on mine failed and could not find any reliable supplier in Europe. There have been stories of companies returning restored packs but then failing again immediately.

The guy in the States seems to know what he is doing and stopped buying from one supplier who was selling him junk. He offers exchange and loaned packs as well. You have to bear in mind huge postage costs and import taxes though.

There is a gap in the market (and I suspect that a good electronics engineer could repair a pack cheaply and easily) but it's such a niche market in Europe that demand will be too low. I'd contact a few independents and explain your predicament and see what they say. MB dealer playing parts darts will soon drain your dosh!

 

[V6Matty]

As mentioned you’ve got Wayne gates in Harrow or as you say you don’t mind a little bit of travel, there @alexanderfoti of AMFAutomotive in Trowbridge

 

[s5tuart]

As mentioned you’ve got Wayne gates in Harrow or as you say you don’t mind a little bit of travel, there @alexanderfoti of AMFAutomotive in Trowbridge

Alex is a regular contributor on the forum.

 

[V6Matty]

Alex is a regular contributor on the forum.

He has a thing for the V12’s too

 

[Wighty]

I’m fairly sure it is that side that was changed - the new coil pack is on passenger side of the car (UK RHD), part no 2751500780. I believe that cylinders 1-6 are on the driver side, and 7-12 on passenger side. If I am right about that, the fault is on the side with the new coil pack.

There has got to be a years warranty on an MB fitted part ?
Alexander Foti on this forum knows about the 65 engines (he has one ) @alexanderfoti , he is based in Kent and runs AMF Mercedes .
Ian runs Star Mercedes near Reading is on the forum as well @star

 

[SL63 Mark]

As mentioned you’ve got Wayne gates in Harrow or as you say you don’t mind a little bit of travel, there @alexanderfoti of AMFAutomotive in Trowbridge

I thought Alex was in Tonbridge, not Trowbridge ?

 

[JBell]

There has got to be a years warranty on an MB fitted part ?

2 years IIRC

 

[alexanderfoti]

I’m fairly sure it is that side that was changed - the new coil pack is on passenger side of the car (UK RHD), part no 2751500780. I believe that cylinders 1-6 are on the driver side, and 7-12 on passenger side. If I am right about that, the fault is on the side with the new coil pack.

Yes that is correct, 1-6 drivers side 7-12 passenger side.

There has got to be a years warranty on an MB fitted part ?
Alexander Foti on this forum knows about the 65 engines (he has one ) @alexanderfoti , he is based in Kent and runs AMF Mercedes .
Ian runs Star Mercedes near Reading is on the forum as well @star

Appreciate the mention! I do love a V12 3 sitting in the car part ATM. My other one is at home.

We look after a handfull of them. As above, you cannot go wrong with Terry at Wayne gates, but we are happy to look as well. Ultimately it needs a bit of diagnosing first before doing anything else, not worth throwing the same parts at it over and over at great £££

 

[V6Matty]

I thought Alex was in Tonbridge, not Trowbridge ?

Oops, you’re right he is, I don’t know why I put Trowbridge

 

[Wighty]

Oops, you’re right he is, I don’t know why I put Trowbridge

I’m sure it was a spellcheck/autocorrect problem

 

[Botus]

there is a number of youtube videos that explains in depth exactly how "interesting" the ignition system is - its by an electronic guru that owns his own business and owns a Merc w221 V12 that misfired

the gist is a single cyl misfire can destroy the entire coil pack (12 coils sticks) and this usually blows out the brains of the voltage transformer whenever you have a single individual stick failure.... once the VT is damaged fitting new coil pack is futile - they almost certainly self destruct within a few miles and its just at 1500 quid waste of time and money

www.v12icpack.com

a few months back spent 2 hours watching his videos of what goes wrong...

the iron core inside each of the 24 OEM coil sticks breakdowns with time (not mileage), often randomly with any of the 24 coil sticks dying around the 11 year mark, as this fails the windings short and can send voltage spikes round the system that often blows the brains out of the voltage transformer and or the whole banks coil pack. So one ageing coil stick starting to breakdown starts a chain of events introducing the possibility of three major issues

its quite an odd get up - rather than a coil on top of each plug with its own 12v power supply like the V8s get - the V12 mercs have "two coils sticks per cyl" that swap duties back and forth each spark. One spark its being a 180v main coil, then next spark its an emission clean up spark coming fractional late to the party as a 23v coil. To achieve the magic spark fest, each bank of 12 coil sticks are part of a complex electronic circuit broad making one banks (6 cyls) coil pack.

so the issue usually starts with an owner exercising the car, which makes life harder for any of the coils, and that often brings in a random one cyl coil stick failure. But that can blow the whole coils packs circuit board taking out all 6 cyl on one bank. And or blowing the brains in the separate voltage transformer - this VT is what gets the required 180v / 23v power supply change. Thus one stick starting to age, often ends up giving a two or three cyl misfire as the voltage transformer gets damaged.

However even with good coil packs the voltage transformer can get cooked to death from normal engine heat over time and bring down the whole set up in a costly disaster

Usual scenario one coil stick ageing can bring down the whole lot, and even when the whole 12 stick coil pack on one bank is replaced, a damaged VT (caused as the first stick dies) often ends up killing the replacement coil pack and its a circle of expensive hell and head scratching..

so the fix is three opportunities for a mortgage

remove your voltage transformer (VT) today and exchange it for one of his upgraded longer lasting overhauled VT OEM boxes now with two fuses you can replace - to stop a complaining coil stick sending back a spike and blowing up the the Merc OEM $800 VT unit

then if brave and stupid you can buy a faulty coil stick on ebay and likely trash the whole bank trying to fit one new budget fake coil stick for a cyl you identify as playing up, OR swap out the whole group of coil sticks (made in house via china) with his upgraded coil pack where all sticks have been replaced and re-soldered carefully to the refreshed circuit board

alternate VT option replace the OEM VT and fit his upgraded remote located (for a cooler location) more sophisticated solid state VT box, which can cope with coil sticks throwing teddies and you don't need to play swapping fuses in the rain at the side of the road...

Allegedly the VT, both coil packs, and a set of 24 spark plugs - at circa £5k - should be swapped around the 70k miles and or every 7 year mark

 

[Chrishazle]

Oops, you’re right he is, I don’t know why I put Trowbridge

He's actually rather in the middle of nowhere East of Paddock Wood, near Tonbridge, fun place to find first time as it's up a small access road off a country road and behind large gates that you need the access code (which Alex will send by text to your mobile if you're going there) to open.

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