shotgun_banjo

So I just hit 100,000k on my W204 today and I am due for a B1 Schedule. Dealer told me I need my spark plugs replaced and other few things.

I am just curious what are the indications for the W204 that it is time for new spark plugs? I know there is the typical rough idle, hesitating to start, high fuel consumption that people always talk about but if I do not experience that except for the gas consumption (lead foot of mine) how do someone knows when it is time unless the dealer tells you because MB says so.

Is it best to just replace it for peace of mind? btw car is already 7 years old.

I also want to know what you guys think about the transmission and TQ flush. It was done 2x (1 at 60k and 1 at 72k - because I found out they did not do the TQ flush at 60k so I let them redo it because of the knowledge from this forum). I drive the car really aggressive so when do you guys think I need to do the flush again?

michail71

I've experienced improvements in other cars that I thought were running great. I'd probably do the plugs myself though.

white46

FI, by book, auto tranny service interval is 60000km and spark plug is 91000 miles or 5 years.

It's up to you whether you want to follow to book or not.
Personally, I wouldn't do either.

edgalang

I just recently replaced the spark plugs on my 2012 C350 since I'm now @ 60k miles. I was surprised to see them in such good condition, I am however curious why the M272 motors suggests every 90k miles whereas the M276 says every 60k.

Carsy

I understood that the MB transmission oil change interval was 39,000 miles which included the torque converter.

If you drive hard all the more reason to change on time or before.

There are lots of sad stories written on this forum about those who do not follow this recommendation.

Take a look at the "sticky" on servicing atms at the beginning of the 204 section.Your 7 speed is not as robust as the 5 speed.

Regarding plugs it is always wise to do "preventative maintenance" ie to avoid the symptoms of poor spark.

You own a well engineered car, why do not service it as they suggest in most respects.

shotgun_banjo

I do not mind spending the money on the maintenance but I just want to know if it is reasonable for the spark plugs to get replaced at this mileage and if it will even make any difference. The tranny service I will do at 110k (after 6 months) as it was done at 74k so I think 40k after the initial service is good rather than waiting the car to hit 130k. The brake fluid flush I will do as per recommendation (every 2 years), cabin filter (will be done myself) and the rest will be done by the dealer. It is just the spark plugs is not really part of the B service and was just told by the dealer that it is time to replace.

Edgalang,

Did you see any difference on mileage and how the car runs after replacing the spark plugs on your ride? I watched a youtube video on how to replace the w204 plugs and it is easy and I have the tools but I am just lazy and will let the dealer do it instead.

edgalang

For me, with parts + labor I was quoted $700. The cost + the fact that the M272 is easier to work on than the the M276 and the fact you already have the tools in place with all the YouTube vids, I would definitely try a DIY first.

As far as performance goes, like I mentioned before, the original plugs I pulled were such in a good condition, I doubt it made any difference replacing them at 60k when I did. That being said, I'm still going to follow the maintenance book moving forward regardless of my observations.

c300white

Plat plugs can last 100k+ miles - but cheap and easy diy at 90k/7 years - so why not. I took mine out at 93k and they still look
Fine - but now I'm good for another 90k on my new iridiums

ezshift5

Iridium spark plugs - in my experience - last an almost unbelievably long time.


ez

IGB

It is more than reasonable to at least check spark plugs at that mileage in an attempt to ensure that there are no other issues with the car. If you find that they are in decent condition, then by all means, screw them back in and you're done. Often times, problems do start and since, as a result, performance may gradually degrade, it becomes difficult for us to notice a difference in how the car drives. A spark plug's condition (and I would check each and every one, not just one or two) can be a tell tale sign of other major issues.

As for the transmission service, I cringe at the sight of someone posting they have not or will not change it at the recommended periods!

michail71

But for the cost it's almost worth replacing if you are going to check them at that age.

shotgun_banjo

Okay guys I will replace the spark plugs. What brand is the OEM spark plugs? Are there better plugs out there that you guys will advice getting than the OEM one? If YES, please give brand and part number please. I am guessing I also need to use those dielectric grease correct?

jjcrews01

The OEM plugs are NGK with a Benz symbol on them. I just ordered the recommended NGK p/n w/out paying the extra $$ for the symbol.
My C250 just hit 60k when I changed the plugs; and I did put the anti-seize on the plug threads.

edgalang

The OEM plugs that came in my 2012 are Platinum Iridium Bosch ZR6SII3320

They are roughly $12/each online. (I purchased mine from Amazon).

...and in case anyone has any doubts...

https://content-na.drive.amazonaws.c...mb?viewBox=932

https://content-na.drive.amazonaws.c...mb?viewBox=932

https://content-na.drive.amazonaws.c...mb?viewBox=932


EDIT: This is for M276. Please check to see if they use the same plugs in the M272.

TIPS:
#1 You HAVE to put dielectric grease on or else you'll have a very hard time taking it off afterwards. At the very minimum, smother it on the ceramic part of the plugs.
#2 Do NOT use anti-seize on the plug threads. The threads are already prepped with a coating and it even says to not use anti-seize somewhere on the box.

shotgun_banjo

ok thanks!

shotgun_banjo

Just pulled the plugs yesterday and replaced them. This is what I saw and since this is the first time I pulled my own plugs I have no idea how bad they are. I know you can tell a little bit on what is going on inside the engine when you look at the spark plugs but since I am no mechanic I would like people who are technically inclined to give opinions on what you see here. The motor has 102k when I pulled it out and I believe this is the original spark plugs from the factory.

95Sinned420

Those plugs actually look good. Very normal, no signs to be concerned of. Seems like a healthy engine to me. No visible abnormal wear/corrosion or excessive deposits. The brownish you see is very normal. In fact, if you pull the new plugs after 5k miles, it'll have the exact same brownish color. Keep up the good maintenance

Also, the threads have anti-seize material on it. So if they're original, it must have been applied from factory. I don't recall the boxes having a notation about not using anti-seize. I've never heard of that, actually. I did my plugs several months ago and used it as well.

centfl-c300spt

I changed mine out at around 80,000 miles. Looked really good.
The indy shop I use, I sometimes hang out and watch them change plugs and they never use anti-seize. He recommends using NGKs over Bosch or anything else for NA, regular, plain ole' c300/350s. He said he's never seen any real benefit from anything more expensive.
If you get into tuning, supercharging (v8s), or upgrading turbos (c250s), then you'd want to change your plugs for your application.

74Etoile

if you like confort and driving pleasure with your w204 , change transmission oil interval btw 35000 to 39000 kms and make sure you got the genuine transmission filter , at the same time change your differential oil ...