jhandy1

Hello,
I Recently traded in my 2012 BMW 528 (grampa car) for a 2006 Designo graphite S65 AMG. I was lucky to find one with 55k miles on it.
This car is a blast to drive - seats all my 4 boys comfortably and hauls A$$.
Unlike my BMW or my boxster before that- Under the hood looks like a complex maze of tubes and wires. This car looks very complex.
That means to me that repair will be expensive. So... in a nutshell what pearls of wisdom should I know? What failures should I look for before they turn into expensive trips to the dealer?

I am very mechanically inclined, so short of pulling the motor, I know what I am looking at and can fix it if given a little guidance.

Thanks,
James Handy

Welwynnick

Hi James, and welcome to the club.

Yes, it's difficult to maintain and repair, but it is feasible.

If you want to look after it properly, many people buy themselves a Chines copy of the MB SDS Star Diagnostics System. That gives you all the diagnostics capability of a dealer, plus all the documentation.

Short of that, definitely get an ebay DVD of WIS and EPC - manuals and parts lists.

The self-diagnostic system is very sensitive - don't lose sleep over minor faults. If in doubt stop and start again, and the fault often goes away.

Pay attention to red warning messages, though.

The intercooler system is efficient when working properly, but its difficult to keep it that way.

The ignition system is fragile - ask for advice if you have any misfires.

Pay attention to ABC - especially the posts on routine maintenance - see my signature.

Regards, Nick

maw1124

Nick, thanks for sharing your considerable knowledge so freely on this site. Question for you: do you have any idea why the ignition system is so fragile? I can handle the ABC system, the extra components to break (turbos), turbo lag, and the extra 4 cylinders (and 12 spark plugs). But the ignition coils and modules go bad seemingly 100% of the time, and they are NEVER cheap to repair -- replacement seems the only option. They are impervious to maintenance, and it seems like all V12 MB, not just the AMG models. Any thoughts on why?

maw

ItalianJoe1

The ignition system is fine. Coils fail as they do on any car, with age and mileage. The downside is that they are special and expensive. If you had to replace a coil pack after 10 years, it wouldn't be a big deal on a normal car. It's only a problem because the coils are $1000 each. It's a strong engine, there is nothing like a big v12 merc when it's all working properly.

Just remember, you bought a car that had a 200K sticker price. Maintenance isn't like a Corolla.

amstel78

Any suggestion on which MB SDS system to go with? C3? C4? C5?

ItalianJoe1

The earlier system is fine, the C4 is the most popular. Whichever you use, the older DAS system these cars use is slow, so in an emulator on a laptop, everything takes time. Still worth having, can save you a ton of headaches and lots of money if you are mechanically inclined. Plus there are some neat coding options in the developer mode, which is locked normally on factory scanners.

amstel78

Thanks for the info Joe. I'm still learning about these cars, so please bear with me. Having a look on eBay, I see mostly these units on sale for anywhere from $450-800 depending on if it comes with a laptop or not.
http://www.ebay.com/itm/New-V2016-07...3&var=&vxp=mtr

Is there something less expensive, similar to Vagcom (VW/Audi), which consists of an OBDII to USB cable and software that runs on any Windows PC?

I don't mind coughing up $500 if the above link is the only thing I can get, but I would only end up using it a handful of times, that I think it's not really worth the investment. OTOH, if there's something akin to a Vagcom cable that's in the $100-200 range and can do the same thing, that's more reasonable.

maw1124

That's a fair comment, although MB chose to do coils a bank at a time in the V12s only (a curious choice), not a cylinder at a time as most manufacturers. So if one coil goes, you're replacing 6. Ok...

Like many of you, I maintain a fleet of personal cars, so I'm not looking for any of this to be cheap. But why do the ignition modules seem to go bad WITH the coils? Or am I wrong on that? A coil every ten years, fine. 6 or 12 every ten years, you're pushing it. 6 or 12, plus the modules every ten years, I'll take the blown V8 with individual coils, less maintenance cost, less weight and just as much "useable" power, thank you very much.

maw

Welwynnick

The problem with the ignition system is that there's very little space available for the coils (and there are 24 of them, remember).

Each coil is stuck on top of each plug, in the tunnel that the plugs are fitted through. Therefore the coils are small, and difficult to cool. They tend to overheat, and that is the main problem.

Fitting V12 N/A plugs is a common mistake, and these have 1.0mm vs 0.7mm gaps. That over-stresses the coils, as they have to generate a higher voltage.

A tune increases the boost pressure, and also increases the voltage required to spark, so that often appears to break previously good coil packs.

You don't have to replace a whole coil pack to fix one or two miss-firing coils. You can replace them individually.

You can buy new coils by MotorKing (they're called Mercedes V12 ignition cassette) and fit yourself (DIY, but not trivial).

Alternatively you can salvage serviceable coils from an old misfiring coil pack, and fit those. I've done that, and it works fine.

Or the coil packs can be rebuilt; these guys are highly recommended round here:
http://www.v12icpack.com/

Regards, Nick

maw1124

Thanks, Nick. That sounds like: (1) run the coolest and best .7mm iridium plug money can buy; (2) stay away from the tunes (bad for the ignition system AND the transmission); and (3) stay on top of the maintenance. I have an electronics guy who can't tend to the transistors. Have you experienced failures following these practices?

The heat and vibration are huge culprits though. I don't know if people here recall, but ignition modules were a problem on early year E55k cars, where the engine designed for the larger engine bay of the S and SL were shoved into the E, and (I think) one of the heat exchangers removed. The result was bad modules. By '05, MB had remedied it but I don't know how. I wonder why no one has designed a heat shield or plate to sit between the engine and the module.

maw

ItalianJoe1

The reasoning for the coil system was lack of an ECU that could control 24 coils. The newer cars they only have 12 coils and a newer ECU that runs them. This multi coil system fired them with a slight split and used ion sensing for knock detection and individual cylinder timing optimization. It's too much for an ECU from the 90s to handle, so the coil management is in the coil pack units themselves, and the voltages they need are fed by the transformer unit.

Most failures of "everything at once" are mis-diagnosis, as the transformer dies and you lose a bank, most people start with the coil pack, then the transformer. People who haven't removed them before or are just unlucky (like me on my personal car), have a coil pack break off when removing, and end up replacing them instead of just doing plugs. I've done plug swaps on customer cars with no issues, but on my CL I had the front coil stay in the head when removing the right pack. $900 mistake, but life goes on. I will change the transformer next to address my hot restart issues, as doing all the plugs didn't help it at all, nor did one coil.

The other downside to this system is the lack of internal diagnostics. Compared to most MB systems, which have tons of fault codes for very specific things, there is comparatively little in the way of self diagnosis for the transformer and coils. It is largely a "replace and see what happens" even at the factory level. These cars were rare and expensive so it never got past that stage.

g60wall

I have the hit restart misfire on my S600, I got new coil packs, voltage transformer, and mb plugs. Still misfired when super hot. So I started data logging and found that the iat on start up are 170-180 so it misfires. Cause the intake charge is to hot. My solution, let key sit in on 2 click position to let coolant circulate(I read that it circulate the ic coolant with just the key in the on position) and will be to get the IC system properly purged.