V12 check engine, spark plug question
my car was running fine, during a recent check on my ABC, my dealer claims the check engine light's one and i got "misfire" code - it's a 2005 S600 and the wiring's been replaced, but they think it's still the original plugs for 59k miles(i plan to verify).
here are my questions:
1. does the OEM come w/ Platinum plugs, and don't they usually last 100k miles?
2. how much should new plugs, and how much should labor be for that?
3. it's an MB dealer - does anyone have suggestions as what i should do? thx in advance.
Patrick

I think book time is 4.5hrs approx both coils, air intakes have to be removed
and remember its 24 plugs which add to the cost..
If you want shop around BUT just remember each coil is 1200 and they are very easy( VERY EASY) to break so proceed with caution
About $250 for plugs OEM from dealer, about $500 labor from dealer.
Coil packs are delicate. And why can't the check engine light be from a coil pack? How do they know it's plugs and not a coil pack?
Bruce




There are DIYs posted here. But the long of the short of it is it'll cost you $1200+ at the dealer. If you can do it on your own, budget 6 hours on a nice day. It'll suck if it starts to rain halfway through the job. You'll need to get the V12 ignition coil extractor tool and you'll definitely need several angle adapters for your ratchet.
There are 24 plugs in this motor. I replaced the plugs with standard NGKs @ about $2.50 each. Add to that the tools required and I was out $250 - a lot less than $1200.
Plan to swear a lot and have band-aids ready too. Those last three cylinders (two on the driver's side and one on the pass. side) are a bear to reach. If you have the time and interest, you might aswell do it yourself.
Hope this helps a bit
Best from Boston,
-dan
2005 S55 ///AMG
my car was running fine, during a recent check on my ABC, my dealer claims the check engine light's one and i got "misfire" code - it's a 2005 S600 and the wiring's been replaced, but they think it's still the original plugs for 59k miles(i plan to verify).
here are my questions:
1. does the OEM come w/ Platinum plugs, and don't they usually last 100k miles?
2. how much should new plugs, and how much should labor be for that?
3. it's an MB dealer - does anyone have suggestions as what i should do? thx in advance.
Patrick
had "check engine" light on and took car to MB dealer.
good news is i had extended warranty cover the $2,000 for new coil pack.
bad news, i drove the car for 20 miles and the check engine light goes on, AGAIN.
now, the dealer says new plugs required as it's been 5 yrs and 63k miles.
dealer quoting $1200. i'm asking him how much is parts vs. labor, because i feel like they KNEW the plugs were 5 yrs old while changing the coil packs, and i could have changed plugs at that time - would have saved me the labor(at least for the 6 cylinders?).
any input from you guys on this situation would be appreciated.
Patrick
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As in the title, yep, they are a royal PITA. Your 2005 has a Twin turbo V12 (M275) which really doesn't like to come apart. The cost to replace spark plugs is commonly set at $1200-1400 (frightening ain't it?) and the reason is labor time. They charge you about $10 per plug (there are 24 of those) and the remainder is getting into the motor and installing them (~6 hours)
The upshot is, if you're ok with wrenching it yourself, replacing spark plugs is definitely something you can do in your driveway/garage. You'll need the tool to remove the ignition coils (there are two of them, one for each bank) and you'll need a tool to remove those (~$150 last I checked). You may want an articulating bit for your wrench ($15) and I used standard 2-pole plugs ($2.50 each) when I did it in my V12. Budget about 5-6 hours to do. Yes. HOURS, along with commensurate quantities of beer and gifts for your wife for the swearing you're likely to do in the process.
There is a tutorial on here that describes the procedure from stem to stern, so do a quick search for that. The short version is: remove engine cover, aircleaner and disconnect the intercoolers. Tie those up onto the hood using zip ties or similar. remove the heat shields over the exhaust manifolds, and use the tool to remove the ignition coils. Please be very careful when handling those as they are fragile and costly to replace. remove/replace each spark plug per common convention with a wrench, extension and spark plug bit. It's useful to have an articulating bit to get into the very last 2 cylinders, particularly on the driver's side as the brake booster and fuel lines are right there and tend to get in the way a bit. Put it all back together in the reverse order.
Do it yourself and you save ~$1000 or so but don't be in a hurry.
had "check engine" light on and took car to MB dealer.
good news is i had extended warranty cover the $2,000 for new coil pack.
bad news, i drove the car for 20 miles and the check engine light goes on, AGAIN.
now, the dealer says new plugs required as it's been 5 yrs and 63k miles.
dealer quoting $1200. i'm asking him how much is parts vs. labor, because i feel like they KNEW the plugs were 5 yrs old while changing the coil packs, and i could have changed plugs at that time - would have saved me the labor(at least for the 6 cylinders?).
any input from you guys on this situation would be appreciated.
Patrick
The Best of Mercedes & AMG
My 2005 S600 had the NGK Mercedes branded iridium plugs from the factory as well. I've replaced two sets over the years on my own (I can get it all done in about an hour and a half...two hours if the socket or screw falls onto the belly pan and I have to fish it out). Replaced the first set with NGK laser iridiums, second set I figured I'd try the Bosch double platinums since they were on sale (and at 24 plugs it was worth it). I can honestly say I can't tell a difference between the two even driving it hard.
You may also look at replacing the pressure sensor and temp sensor in the V (under the voltage regulator unit that runs to the coilpacks). Mine were fouled and caused misfire issues after replacing the coilpacks (which were definitley bad).
http://www.mercedestechstore.com/pdf...2008-06-03.pdf
...pages 40-46. I was referring to the Air Pressure sensor (B28/7) and the Charge Air Temp Sensor (B17/8). The temp sensor in my case was fouled and causing misfires even after replacing the coil packs and spark plugs. Also, the car will run like crap (cuts the turbos and won't shift properly) if the B28/6 sensor is disconnected or the tube is not attached (but not a misfire).

Keith



