Totally your call about buying vs.renting. I think I would try Clark's rental program for both on the off-chance you end up needing it. Give Clark a call and see if he will rent you two CPs and a VT Boost Box. Since his Boost Box is so new, he may only sell that component. I bought it. I also bought my CPs but I knew what my problems were and I wanted the car back to spec in all ways. I also had the money.

 

Alright thank you for the help. I'll have an update on if that fixes the car or not.

 

Actually before that. I'm taking out the driver side spark plugs right now. Up to this point it has been obvious that someone's been in here before which I guess wouldn't be surprising to change the spark plugs. But there's also some original inserts in the coils themselves. Most of them are new but there are a couple original ones. Would Mercedes have replaced those with new ones or did some guy like me replace the spark plugs but not take out the stick inserts. Also the valve covers bolts aren't that tight. Could be the torque spec but my regular bit driver can easily remove them. And the last thing is there is a lot of oil in the plug wells on the driver side. Haven't taken out the spark plugs on the passenger side where I'm having the misfire issue but I'm sure that could easily cause issues.

 

My valve covers were also loose and was probably the cause of my oil leaks into the spark plugs and coil packs. If you can see any electrical discharges on the older inserts that actually produce a hole, you should replace them. A new CP will come will all new inserts.

 

Alright cool. Just thought it was weird that the driver side has some old ones and some new ones. Maybe someone replaced the coils before to fix the usual 7-12 misfire that normally happens

 

On the website https://www.v12icpack.com/ the service is offered to replace a single coil. Better money to get one complete side refurbished as that resets the clock.
The CP’s from MB have a finite life. The CP’s from Clark have a longer finite life due to upgraded components and of course keep the oil out of spark plug wells.
The VT, Boost Box has upgraded industrial components, fused, and located in a cooler spot.

If you can muster up the money, call Clark Rupp, do the work yourself, make a nice sandwich:
Remove old left/right coil packs.
Remove oil soaked spark plugs
Install new valve cover gaskets and tighten spline bolts to spec.
Clean spark plug wells with Egyptian cotton towels.
Install new spark plugs, verify gap, and torque to spec. Anti seize goop is optional.
Install new refurbished left/right coil packs from Clark.
Remove old VT on top of engine, and replace with the brand new Boost Box from Clark and mount it on the much cooler temperature firewall out of the way of the left/right windshield wiper armatures.

The engine will run like new for 70k miles or more.

Johnny

 

in one of my first posts to you, I believe I made if quite clear reading the bit now repeated below would be a wise move... I'd given that link and within the v12 repair site link for Clark, and my interpretation of the interconnections of worn bits causing failure of new bits

until I studied his video I didn't understand the points he's making - but I was very well aware - VIRTUALLY ALL V12 OWNERS GET A MISFIRE, BUY A NEW COIL PACK AND BLOW ITS BRAINS OUT WITHIN THE WEEK - as these packs are so costly its not a good way forward for most owners


https://mbworld.org/forums/s-class-w...ml#post8755102

last night spent 2 hours watching that guys 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 fractionally 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 board making one bank's (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 coil packs circuit board taking out multiple cyls 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 coil 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 this can 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 died) 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 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 option replace the OEM VT and fit his upgraded remote located (for a cooler location) more sophisticated VT box which I guess can cope in solid state 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 $7k - should be swapped around the 70k miles and or every 7 year mark


https://www.v12icpack.com/

 

The final update is I replaced the coil pack. I decided not you go with Clark's because of how long it would take to receive it. This is my only car so I didn't want to wait till late August or September to receive it. But the replacement one did fix my issue and it's back to running strong.

 

Great news. I am not surprised a coil pack was the problem. The big weaknesses in the W221 V12 are ignition (coil pack and VT), spark plugs, ABC filter and fluid, and front lower control arms. Keep up with the maintenance on each of these systems and your S600 will be very good.

 

XX, thanks for the detailed explanation of your experience. This adds to the collective consciousness of the forum in helping us diagnosis our cars. Having been there, finding whether you have a bad CP vs a bad VT is a daunting task; like putting $1000 on “red" or "black" at the roulette table-- and you can always still get "green" with the bet…

Glad to see your reasoned decision was correct…

Regards… Mark