Taiwanese

My car is 6 years old and 45k miles. After reading this post I wanted to change all the spark plugs. MB recommends replacing them at 5 years or 80k miles.

This is really simple to do. The whole job takes less than 30 minutes.
Always use common sense and safety first. Do it at your own risk.

Taiwanese

Wow, what a difference!!

Just a short drive afterwards, I am feel the car is more responsive already.

kirax2

thx dude wait.. M111 the same? any differences? i was seraching for it and any spark plug length difference?? anyone know?

shivi1345

you 100% NEED the anti-seize and the grease?

Taiwanese

I would use it. It makes it easier to remove spark plugs in the future.

#4 was so tight that I was afraid I break the plug while taking it out. It was tighten WAY too much at factory.

TruTaing

Taiwanese, you create threads pretty rarely, but whenever ya do, they are very useful

Nice job documenting and sharing!

daiso'

wow this should be on the DIY sticky

Great job!!

Taiwanese

Thanks.

I come here regularly. I love my car but hate to pay outrageous prices just because of that logo on the hood.

I hope others can also save some money (especially nowadays) while maintaining vehicle safety & durability.

richardlo

So you dont need to gap the plugs any?

Taiwanese

I checked and they are OK.

Now, most spark plugs are well packaged with protection on the tip. I don't think re-gap is necessary.

XenonBenz

Do not try to gap these plugs!!!!! You will ruin them.

Both the OEM Bosch and the OEM NGK plugs are pre-gapped to factory spec. These plugs are not "gappable" by design. You will ruin the electrode if you try to gap them. If you check the gap and it is off, then go to the store and exchange it for another spark plug.

Most auto parts stores (Advance, Auto Zone, etc) stock the Bosch & NGK plug for $9.99. MB is now stocking the NGK instead of Bosch. I purchased my plugs from the dealer 2 months ago, and they were NGK plugs.

DEEBEE060

Does anyone know where I can get a new plastic engine cover as per the 2nd picture as mine broke on careful (maybe) extraction. Also the foam underneath was toast. I had to blow it out as it was destroyed dust. Part numbers for foam and cover would be a help as I can order from MB. Rest of the job was a breeze.

EV0LVE

Taiwanese, thank for this thread. I just did mine today. Ler me just add that removal of the ignition coil will take some effort and finesse. Use some brute and it'll crack.

Taiwanese

EVOLVE,

You are so welcome. It's easy, right?

Midnight Koop

great write up! i have an '03 m271, but with twice the miles... i think will use this thread to do the same.

thanks for the contribution and keep them coming!

maverik259

just did mine...'05 c230 w/ 65k miles...for everyone else looking to do this don't forget you'll need a 6" 3/8 extension and a 5/8" adapter to fit over top of the spark plug (like $10 total at advance auto parts)...had oil on cylinder 1 plug, some kind of grime on cylinder 2, and cylinders 3-4 were clean minus the wear...i used the NGK iridium. Runs great as far as i can tell...no real notice in the difference to be honest.

maverik259

cylinders in order from left to right 4-3-2-1...notice the nastiness on #2. Any thoughts?

BabyBenz6spd

Whats the torque spec for these spark plugs?

maverik259

18 n-m i believe.

VelociRaptor

Just done this to my car, takes no time almost. No reason why any red blooded male couldnt do this himself(or adventurous female for that matter). If your in a tight and dont have an E8 socket just use a 1/4" socket, works like a charm. I just tightened them 1/4 turn past finger tight like I do all my other washer type plugs.

samaritrey

Wow nice picture always wanted to do the tour of the plant but always forget to sign up in advanced. I go down to Tuscaloosa 2 or 3 times a year to visit/pickup my friend that goes to UA.

VelociRaptor

PM me the next time you come down.

gillespie_3000

Thank you for the post just finished and everything went flawlessly.

C230 Sport Coup

Just thought I'd share...
last time I went to pull the plugs one did not want to come out.
If you force it you can tear the threads out along with the plug or break it off
in the hole, very bad.
Here's how to deal with that.
1st off never do plugs on an aluminum head that's still hot, let it cool.
Warm is ok, but not hot.
1. Spray some liquid wrench down in the hole, the goal is hit the threads.
Let it sit for a while.
2. Turn the plug gently Counter clockwise (CCW), as much as it will turn without too much effort.
3. Just turn it a little if it's really stuck, and then back again, so counterclockwise, even if it's just 1/8 of a turn and back clockwise.
4. Repeat repeat repeat.
5. The liquid wrench will start to penetrate, apply more if necessary.
6. Keep turning it one way and then the other as you back it out, and then
turn it back slowly getting it to come out.
7. Once out, according to my mechanic apply some
tranny fluid NOT anti sieze to the threads of the new plugs.
Supposedly the anti seize cakes up under extreme heat and has the opposite effect. Any tranny fluid will do.
I haven't pulled my plugs since I tried this, I'll find out how well the tranny fluid trick works when i do.

derecklouthood

Honestly, to think I was actually going to pay the dealer a ridiculous amount to change these!!! After reading this and many other wonderful posts on MB, i'm so happy I got around to doing it and honeslty it was very easy!! Even for someone like myself. Plugs seemed a little seized on the last 2, but with a little patience, no problem!! Be careful with those coil packs... go at it with ease.. they will come out!

No oil whatsoever on inspections, just nice and clean. This weekend is TB cleaning and hopeuflly a reset as well on the Tranny