acr2001

The photos below are of one of my original NGK plugs with only 27,000 miles on it (2005 C240).

So far I only removed 2 plugs and they look identical. I have to get my hands on the right tool before I can remove the other plug wires without damaging them.

I decided to change them because my car was not starting as quickly or smoothly as it should.

I really don't have a clue about how spark plugs should look, but I'm guessing these are pretty well fouled with carbon / oil? Anyone?

dnlow

They look pretty good. I would wait to change them, but if you want it will not hurt. I recently changed my plugs at about 85k and they looked a bit worse than yours, but still acceptable for the miles. I did notice a slightly smoother engine though.

Glyn M Ruck

Mine looked similar at 45,000Km - Bosch though - Changing them stopped the spluttery starts I talked about on the other thread. I would change them as Benz advise. Bosch run a finer centre electrode.

Plugs from fuel injected cars running on lead free fuel always look so damn good compared with the lead errosion & deposits of the past. This can be misleading.

acr2001

Glad to hear that. I actually swapped those 2 for new plugs today (replaced with the same part #). I was going to do all 12 but I can't find a way to remove the other plug wires without damaging them. Going to get the removal tool tomorrow.

Glyn M Ruck

That tool is a good idea - Hanging on the wires is not - as I know you know.

acr2001

Finished swapping all the plugs today. The engine feels smoother and a lot stronger on the low end. Revs up more smoothly too.

Now I have to get the dealer to fix the passenger side recirculating cover which is leaking oil again. They already fixed it once but not surprisingly did a **** job.

LILBENZ230

Is this recirculating cover exclusive to the M112? Or does the M272 family have it, too?

acr2001

The problem with it leaking is specific to the M112. It's probably the most common problem I've heard of on the M112. I'm seriously thinking about fixing it myself even though the car is under warranty. My dealer *really* sucks.

It's pretty easy to fix - https://mbworld.org/forums/c-class-w...ing-cover.html