EnkeiDynamics

Anyone know how to remove them and what is needed to replace them?

I've searched but only to find M271 answers.

I'm getting very slow cranks when starting my car. It's very hesitant to start.
And this morning it took about 4 to 5 seconds for the car to actually start. I'm getting worried

02 C230 Coupe 110k miles
-Never replaced the spark plugs

rtking

Try searching the forums for "NGK Iridiums." Here's a thread:

https://mbworld.org/forums/showthrea...ium+ngk+number

If you're stock, then use the stock heat range:
NGK Iridium BCPR5EIX-11

If you're running a pulley, use a plug that's 2 heat ranges cooler:
BCPR7EIX-11

I am pullied, and just installed the NGK Iridium 7EIX-11 and the car runs smoother, I'm getting less detonation and I feel like I've got more power, and I'm getting slightly better fuel economy. The plugs I pulled out were NGK R Platinums with the MB logo on them, and they had 78K miles.

rtking

To answer the first question: You'll need a T-30 Torx bit or Torx screwdriver to remove the red coil cover. There are three Torx screws that hold that down. Next, you'll need to carefully unclip each of the coil packs and unscrew two screws per coil pack that hold it down. (I forget which size Torx bit is required - maybe T-15?) Pull straight up on the coil pack and that will reveal your sparkplug. Use a sparkplug socket or, if you don't have one, make sure you have needle noise pliers to pick-up the spark plug after loosening. For the NGK Iridiums, they recommend threading them in by hand until the washer seats against the head, the use a ratchet to turn them another half to three-quarters of a turn. BTW, don't just "drop" the sparkplugs into the hole, but use the needle noise pliers to gently lower them in so you don't accidentally change the gap.

As for your cranking problem: If the engine is turning over slowly, you've got a weak battery. If you're turning over just fine, but the engine is not catching, then it could be plugs or something in the fuel system...

EnkeiDynamics

First off thanks for the help,

Ya, thats a good description of it. It's more like the engine is not catching rather than a weak battery. I know what a weak battery sounds like and it's not that. So maybe after I replace the plugs it will be better. Like I said it's ben like 110k miles and they've never been changed. Hope thats it. I would hate to think something would be wrong with the fuel lines. What other symptoms would I have if it was the fuel line?

Thanks for the instructions on how to remove and reinstall as well. I'm going to print them out and buy new plugs soon. Then replace them sometime this week depending on how hard it finding/ordering the plugs.

SeaCoupe

Been reading this, and you are in good hands with Bob. Quite easy to do the plugs. If you find oil in the chambers, don't fret, you need to change the spark plug seals. It happened to me, but I'm at 162k miles.

You may find that you have to order the plugs as these are not that available. At least when I went looking for them.

If you your engine is turning over well, and not starting, I would wonder about the possibility of clogged injectors, or more easily fixed, a plugged up fuel filter. The fuel filter is an easy fix, but it would also show up as hesitation under hard throttle.

The fuel injectors, I keep meaning to do, but have not.

E

C230 Sport Coup

110K miles on original plugs!?
Wow.
Mercedes claims 100K on a set of plugs, but by that time they'd be on their last leg. I'd say every 60K miles.
Slow cranking is likely the battery though, no?
You're officially in the 100K + miles club.
I'm still on my original battery, but I think I'll have to break down and replace it soon, when I pull the alternator and have it rebuilt before it dies and leaves me stranded.

So, sounds like you may have some work to do?
There's lots of stuff the dealer will never do without you asking.
Like:
Ever replace the fuel filter?
Flush your radiator?
Brake fluid? (Every 2 years)
Tranny oil or fluid flush?
Diff oil drain and fill?
Clean the MAF?

Time to break out the tools and get things done. The weather is good, and the beer cold.
You'll notice the difference, especially with the tranny flush, if you have an auto. Waiting till the fuel filter clogs and blows up your fuel pump would be bad.
Troubleshooting is much easier when you don't have to wonder if the parts you didn't replace on time are causing the problem.
Here's the maint. sheet to assist you in getting your car back to tip top shape.
Plugs are easy, like someone said, remove the red cover with an allen wrench, unplug the coil packs, unscrew them, and then unscrew the plugs.

Words to the wise on Aluminum heads.
Do not work on them while they are hot.
Lightly warm is ok, but torque them cold.
Aluminum when it's hot can strip very easy.

I use a magnet to fish out the plugs once they are loose, and the same to feed them into the holes. Don't cross thread!

I haven't used a torque wrench in the past but certainly that would be good.
You can buy special lube for the threads on the plugs also,
there's a kit that includes a special dielectric goo to put on top of the plugs
to make good contact with the coils.
http://www.permatex.com/products/Aut...p_Grease_1.htm
You can get the above along with the thread lube at most auto parts store in a kit for $5.

EnkeiDynamics

Wow that diagram should help alot. I appreciate you taking the time to help me out, all of you guys.

I just got my plugs shipped in this morning so i'm about to head out to the car and start working. I've printed off 2 different sets of directions so i'm sure i'll be fine

And no I haven't had any of that maint. work done. I tried to talk to MB about it when my cars warranty had just run out (about 6months ago) but they were charging redic. prices imo. So i decided not to. I would love to drain my tranny fluid cause it feels like my car is shifting really late and jerky when it does shift. But it could just be me looking for issues. I have a lot more I wanna talk about but it might have to be on another post at a different time.

I'll let you guys know how the install goes in a few hours

EnkeiDynamics

Alright I just finished and took her for a spin and it feels amazingly smoother.

And the crank issue is gone. She cranks immediately just like it should. Nice and strong.

The shifting seems better too and now that I think about it, that might have been b/c of the plugs as well because if I were to down shift on the old plugs it would almost "bog" down as if it didn't have enough ignition to switch to a high RPM or something.

The install was very simple and straight forward. I was very shocked that my dad had all the right tools considering we've never owned an MB.

I've been slowly thinking over the past 6 to 8 months that something wasn't quite right and I think I finally fixed it

It put the spark back in the relationship with my car!

Thanks guys!

PS I think next i'm going to start researching for a replacement fuel filter and then start on tranny, brake flushes etc.

Also I have replaced my MAF sensor about 6months ago, surprisingly easy!

splinter

That is great news. When rtking, emrliquidlife, and C230 Sport Coup reply to a M111 query, you will have indeed received the straight scoop. Those guys are sharp.

Pleased you’ve gotten it squared away.

C230 Sport Coup

Sounds like you've decided to make the commitment to keep the car, and
make it reliable.
I'm glad! The M111 rules!

rtking

Thanks for the kudos, Splinter! I would have said that if Spinter, Emrliquidlife and C230 Sport Coup provided advice, it's best to heed that advice. That's what I did when I looked for spark plugs for my M111 (which were the NGK Iridiums.)

Glad that the plugs worked out for you and you have renewed enthusiasm for the car! Let us know how your gas mileage turns out. I have noticed improved mileage - about 1 mpg in city driving. (I haven't tried a long highway drive yet.) I think some of this is due to a more responsive and smoother running motor and less need for throttle to get the car moving (less bog.)

datgai

Hmm... maybe I'll give this a shot. Too bad I just replaced my sparkplugs <5000 mi ago.