johnand

Attached are the WIS documents for spark plug replacement on the M272 engine. I am at 85K now so I am getting ready to replace them.

billbillw

John,
Are you going to buy the special Mercedes spark plug wrench or try it with a standard plug socket and a u-joint? Let us know how it goes either way.

Thanks for posting these. I've got awhile before I need to do mine, but its nice to know the docs are here.

pcy

In the Spark Plug replacement WIS, step 1 is "Turn key in ignition switch into position 0". I wonder why they want you to keep the key in position 0. I would've thought to remove the key entirely from the ignition since you 'd be working with the spark plug cables and ignition coils.

I was expecting the step 1 to be "make sure the keys are not in the ignition".

johnand

Already had one of the plugs out when I was diagnosing my starting issue. I used a standard 5/8-16mm spark plug socket with no swivel or u-joint. Worked perfectly, so no I will not be buying the MB spark plug socket. I see no good reason to on the M272.

I noticed that too. From what I have deciphered MB meaning of key in position "0", translates to no key in the ignition and/or ignition off. Don't think the coils are energized in the "0" position. I will personally keep my key out of the ignition when replacing the plugs.

I will probably replace the spark plug connectors too just in case.

C230 Sport Coup

So, out of curiousity are there 6 plugs or 12?
Ha, you have the CP's right on top of the plug like the M111.
Well, you don't need wires, but the CP's get cooked from the heat.

pcy

My '07 C280 (with M272 engine) has 6 spark plugs.

mighty mak

I just replaced my plugs last month with the keys out, the car seems fine. Do you know why it would have to be in position 0?

phister

which spark plugs did you go with John? NGK?

pcy

I think "Turn key in ignition switch into position 0" is equivalent to the following - NOT to have the key in the ignition. Position 0 in the ignition is same as key off except the steering is unlocked.

I see no other reason to have the key in the ignition (even in postion 0) while replacing the spark plugs.

johnand

The OEM Bosch Platinum/Iridium.

e1000

Spark plug replacement on the M272 is very easy and straightforward without the need of any special tools or equipment beyond what every DIY'er should already have.

M272 only requires 1 plug per cylinder.

Midnight Koop

out of curiosity.... did you replace the coils too?

i'm about to buy a set of plugs for my m271 and was wondering if replacing coils is something i should do too..

pcy

Unless there is anything wrong with the existing coils, no need to change them.

carbonfiberwhor

Seems pretty easy. Thanks for the links!

carbonfiberwhor

Did this the other day, extrememly simple and can definitely feel the improvement

zerocover

So what plugs did you go with?

Also how often should we change these? I was under the impression that platinum plugs last for 100,000 miles.

Moreira_C230

Unfortunately I can't add any more than has been added above, but after looking at the set up, it does not look like it would be very hard to do at all. I love how much room there is to work with the 272 engine.

Glyn M Ruck

They are good for 100K if you run them in the self cleaning range for most of their life. If you potter around town & do many short trips they will not go that distance.

carbonfiberwhor

I used the stock ones. No point in changing that since they ran me very well

SkankZ

2006 C230. I'm at 46,500 miles and it's time for Service B. A indy quote me $500 for service B and change of spark plugs.

Is it time for me to change my spark plugs also? I've seen thread where people replace it at higher mileages.

Thanks

kluvsbenz

On my 06 C350, spark plugs were recommended at 78k. It may be different on yours. Look in your manual.

johnand

For some strange reason MB lists 06 C-class with a 5year/78K change interval and 07 C-Class as a 5year/91K change interval. Even though there was no major changes from 06-07 on the M272 engines, and both 06 and 07 use the same spark plug number.

As Glyn pointed out if you run mostly highway you can get 100K out of them. I have 100K on mine in my 07, and they look damn good, so I have yet to replace them. Plan on replacing them shortly though.

kluvsbenz

That was my assessment from looking at my spark plugs at 90k. They seem fine to me. I believe I will wait until I pass the century mark before I give them another look.

RedStripe

I had one bunk downstream oxygen sensor that was causing the opposite bank to run pig rich, at a ST fuel trim of -25%!!
Anyway, even at only 70k miles, it didn't take long of it running that rich for it to foul one entire bank's worth of plugs in a hurry!
Replaced with OEM Bosch, something like $80 for all 6 (ouch!).
And then of course the 15 minutes it took to change was a breeze.

elektron3030

This is super old, but I was wondering why as well. Then it dawned on me. This is a service program, so the customers' keys stay in the ignition I'm sure.