V12 check engine, spark plug question
 

hi all,

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

If i recall its 5yrs or 75k for the plugs in the v12s and yes they are platinum..

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

^^^^ Accurate.

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

Bet you it's the coil pack they are failure prone

+1...coil pack. Factory plugs have a mercedes emblem imprinted on them. My car had NGK laser iridium not platinum from the factory.

ask the dealer, and it'll hurt your wallet A LOT
 

I had a CL600 (5.8L M137 V12) and while that motor is not quite identical, it's close enough to the one in your 2005. I replaced my plugs en-masse on my own rather than taking to the dealer. At the same time that I was in there, I did air filters, a thorough engine-cleaning, oil change, and radiator flush. Id probably do the transmission too. This is all normal stuff that should be done at routine (and usually more frequent than Mercedes recommends) intervals

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

hi all,

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

Yep, Spark Plugs are a PITA
 

Hi Patrick

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.

Hey bzlite , what company did you get extended warranty through, how many years mileage and price ? Send me a pm with the info thanks

+1 Coilpack as well...
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).

is that the fuel pressure sensor? what temp sensor?

Sorry, been out of town...Look at this

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).

this is awesome stuff, unfortunately my car is an 01 without these items. I just replaced the MAP sensor and change over control valves. will see if this works. if not pulling the .44 mag out and taking aim center mass of the problem!!

This reminds me of a story when I was younger in the 1970s. My friend, Randy, AKA Randall "The Vandal" Smith, could not get his Belvedere to start in the morning. Tried for 15 minutes and got discouraged and went in to call his boss. Boss man said he had to be at work or find another job. This did not sit lightly with Randall the Vandal so he took out his 17 shot Marlin .22 and unloaded the entire magazine into the front end of the car in front of his duplex. The neighbors came out to see what was going on and Randy calmly got back into the car and turned the key. Started right up! :nix:

Keith:zoom:

if i knew this would solve the problem like Randy, I would do it. changed MAP, change over valves, light still comes on. But, the light only comes on when car is at operating temp, only at idle in gear at stop light. goes from right bank misfire, to left bank misfire. any clues? coil packs, transformer, spark plugs, map sensor, air change over valves have all been replace plus ECM has been checked/repaired. any clues? anyone?