RENNtech-er

My 2004 SL600 (with RENNtech chips, turbo cooler upgrades) is in the local MB dealer for an "A" service at 26,000 miles. The Service Rep is suggesting that all 12 spark plugs be changed out based on age (~7 years). I'm a long time gearhead. My understanding is that the plugs in the 230 series SL600 are good for 100,000 miles. Age, absent any actual usage (mileage), has nothing to do with replacement considerations. There are no codes showing any misfires or any other anomalies. Am I missing something here, and the plugs should be changed, or is this an attempt at an "up sell" that has no benefit? Thanks for the help!

Lee Wireless

Wrong. 4 years or 100k in my 230 per the manual. I changed mine at 50k and 4 1/2 years and they definitely needed to be changed. Go with OEM plugs unless you want to waste money.

IngenereAMG

Give your car a new set of plugs, it will be happier. You spent all the extra money on performance upgrades, it is false economy to neglect the basics.

RENNtech-er

I appreciate the advice, guys. I will look into the cost of parts, and doing the plug change myself. The dealer wants $1,400.

TMC M5

Actually, the V12TT has 24 plugs (2 per cylinder). I believe that the new guidance from MB recommends that the spark plugs on the V12TT's be changed every 60K miles or 5 years. There is a thread over in the M275 V12 Biturbo technical section:

https://mbworld.org/forums/m275-v12-...ark-plugs.html

I bought the OEM plugs from Advanced Autoparts for about 1/2 the price the stealership charges. The detail is in the other thread. The labor cost is $700+ at the dealership because it supposedly takes 6 hours to do.

Tom

NEMES1S

anyone try any other plug than a bosch or ngk? just curious if anyone saw any results with a pulstar or e3 plug

TMC M5

My MB Master Tech who has had his hand in a number of mods to a bunch of V12TT's...was a little reluctant to go with something outside the NGK's when I brought up the pulstars.

BTW...GBR!!! (I am a huge Husker fan)

Tom

NEMES1S

A friend of mine tried the pulstars in his vette andsaid he didn't care for them, just tryin to verify that....and good to hear there are husker fans allover, its kinda the only thing we have around here aside from bars full of drunk collge girls

MustGoFaster

I just looked it up in my 04 SL600 service booklet. It says to replace spark plugs at approximately every 60,000 miles or 5 years on the 275 engines.

NCE500

+1. The 05 SL600 service booklet says to replace spark plugs at 60,000 miles or 5 years on the 275 engine. Although my car with 20K on the odo runs perfectly, I'm going to have my dealer do them sometime over the Summer. While I would usually at least consider doing this myself, there is a lot to get to on the V12 as part of changing the plugs, and I'll pay someone to do them.

atebit

That may be, but $1400 just to change the plugs?? I hope my local MB-centric Indy is more reasonable than that!

mchapman2

Does any one have the procedures for changing the plugs in the 2004 SL600?

V12TTenthusiast

Wow $1400 for a plug job, MB must be charging you $30+ a pop per plug. You can get the required NGK plugs that are needed for the M275 for about 8-15 per plug, just have to look around. It may not sound like a lot but when there's 24 plus to replace it adds up quick. As for the labor time you can do it in 2 hrs but book time says its 4.7 hrs on Alldata

If you like I can send you the step by step pdf if you plan on doing it yourself.

Davesca

Yes, if you have the PDF, I would appreciate a copy.

Thanks.

V12TTenthusiast

Here's the PDFs attached to the post.

Torque: 25 nm (18lb ft)
Gap: 0.7 mm (0.028 in)
Sparkplug: NGK IFR6QG

Here's the step by step for removal of coil packs

1 Remove engine trim panel
2 Remove left or right air cleaner housing (1)
3 Disconnect left or right charge air duct upstream of charge air cooler (2) at turbocharger
4 Disconnect charge air duct downstream of charge air cooler (4) at left or right charge air cooler (3)
NOTE: Installation: Check charge air duct downstream of charge air cooler (4) and hose clamps, replace if required.
5 Slacken left or right charge air cooler (3), to do so unscrew bolts (6)
6 Disconnect pneumatic line (5a) at charge air cooler (3)
When removing right ignition coil module
NOTE: Installation: Check pneumatic line (5a) and hose clamp, replace if required.
7 Dismount pneumatic line (5c) at charge air cooler (3)
When removing right ignition coil module
NOTE: Installation: Replace cable straps.
8 Disconnect electrical connector at pressure sensor upstream of throttle valve actuator (B28/6) and dismount pressure sensor upstream of throttle valve actuator (B28/6) from bracket (5)
When removing right ignition coil module
CAUTION: The pneumatic line (5b) is bonded with the fitting at the charge air cooler (3) This connection must not be separated, otherwise this can lead to leakage.
9 Unclip connector of 02 left probe, upstream TWC (G3/3x1) or of 02 right probe, upstream TWC (G3/4x1) from retaining spring of rear charge air cooler (3)
10 Tilt left or right charge air cooler (3) toward top and hang with hook on engine hood
CAUTION: Close air outlet at turbocharger, otherwise parts could fall in and this leads to engine damage.
NOTE: Installation: Install new O-ring.
11 Dismount left or right bracket (9,11)
Bolt of bracket to ignition coil module: 8 Nm
12 Unhinge switchover valves (14) and dismount bracket (13)
When removing right ignition coil module.
13 Disconnect electrical connector (7, 10) of ECI ignition module, left cylinder bank (N92/2) or of ECI ignition module, right cylinder bank (N92/1)
14 Unscrew bolts (8, 12) of ECI ignition module, left cylinder bank (N92/2) or of ECI ignition module, right cylinder bank (N92/1)
Bolt of ignition coil module to cylinder head: 8 Nm
15 Remove ECI ignition module, left cylinder bank (N92/2) or ECI ignition module, right cylinder bank (N92/1) with a special tool
NOTE: Position special tool on two points and carefully pry off ECI ignition module, left cylinder bank (N92/2) or ECI ignition module, right cylinder bank (N92/1)
See "Special Tools" below.
16 Install in the reverse order
17 Read out DTC memory.
Connect STAR DIAGNOSIS and read out fault memory

Hope the pdfs and texts help

Davesca

Cool, thanks !! My father was a mechanic, so I have basic mechanical skills, and should be able to do this.

NEMES1S

I didn't put in a new o ring on the charge pipe going into the intercooler, I wonder if I have any boost leak issues. Would that throw a code if I did?