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This PDF is not from the correct engine. This is from AllData. Just sent them a note notifying them that this engine is not in the 2012 + E's. This is a confusion mess, mad possible by people on youtube that had no idea that MB changed the engine significantly in 2012 to Gas Injection. The spark plugs suck to do. No doubt about it. But you can do them. You cannot pull the cover off, there is none. That "black cover" is actaully the manifold. Although some people have claimed to have done this without pulling the manifold, you are better than me. I pulled the manifold. It was not really that hard and it gave much better working space when dealing with everything else you have to work on. As for the gaskets on the manifold, I reused mine, MerCruiser boats makes a gasket product that "helps" gaskets. Works great at resealing used gaskets that really have no problem.
You will need a special spark plug wrench. a 14mm 12point socket, it is the ONLY wrench that will work. also, if you don't have a plug puller, get one. Its a *****, I have enclosed two articles for you. First is how to remove the manifold, the second is how to removed the plugs without removing the manifold. Your call. It's like everything else. Take your time, don't be rushed.
Remember these are aluminum blocks. That means DON'T go over the time period for the plugs. The Plugs will become a permanent part of your engine. I post this becasue like many, I was pretty frustrated at trying to figure this out. My dealer quoted my like $400. Book rate. This is not them ripping you off, its a time intensive job. But its not the end of the world. Hope this helps. Good luck!
First, thanks Searay, excellent write-up. I just changed the plugs to my 2013 C350. It is basically the same engine that Searay posted in his PDF. The only difference is that my harness wraps around the ECU.
Note: I did not remove the manifold, I tackled the locking clips on the coils from the side.
Here is my experience:
1) Searay the clamp to the airfilter is not a one time use. Buy a Click-R plier and you can reuse them. It's about $15 on Amazon.
2) Start with the airfilter side. This way you will see how things work and get practice for the really tough side (drivers side).
3) I used electrical tape to ensure that I am not fishing for my tools. See pics.
4) This may not be proper but I find taking off the coils easier if I removed the safety lock from the coil. The safety lock is gray and if you keep applying force it will just shoot off and fly across the room. But be careful you can break the connector when the grey lock is not on. Also as Sea Ray said you must press down once you unlock the connector. When I reinstalled without the grey locking tab you will hear a click which was music to my ears.
5) the 14 mm (12 point) tool can be found in AutoZone for $6.99.
6) On the driver’s side I snipped the tie downs and replaced them which is much easier than trying to pull them out from the base.
7) taking out the ECU was a pita. As Searay said it takes force. After I got it out I applied wheel bearing gease to all the grommets. It will be easier to remove next time.
Click-R pliers
Tape on my socket so it doesn't detach.
Tape on my universal socket and 14 mm socket, aain so they won't accidentally fall off.
I snipped all my zip ties (driver side) and replaced with new ones.
Last edited by Chriztofor; 04-01-2018 at 01:53 AM.
Hi guys, my apologies, cannot open the PDF (in fact, have never been able to open a PDF on here, is this some kind of extra-cost feature?) Anyway, curious the mention of ECU, can you clarify what's involved there?
Excellent post on the spark plug change SeaRay45DB! I needed that for a 2013 C300 and a 2013 E350 I just got. I could not find a video (or info) on changing the plugs in my 2013 S550. So I did my own. First time video. First time Youtube:
I've heard platinum spark plugs can get stuck in engines. Is this true? If so, is it possible to prevent?
There has been a long-standing rumor, longer than the promised 100,000-mile lifetime of platinum spark plugs, that these plugs tend to get stuck in place. The concept behind the rumor is that because the plug is made of platinum, contact with the steel or aluminum of the engine's head results in galvanic corrosionsurface degradation that happens when dissimilar metals are in contact with each other in an electrolyte, in this case, water. The theory is that this process fouls the threads of the plug and fuses it in place.
The problem with this logic is that the threaded end of the plug that contacts the engine's head isn't made of platinum, it's made of plated steel just like any other plug (and that plating should resist galvanic corrosion with an aluminum head). The platinum component is the center electrode nestled at the core of the ceramic insulator. It never comes into contact with the rest of the engine.
That being said, spark plugs of all types can be tough to remove after a few years in place. Whenever checking or replacing a plug, we like to dab a bit of antiseize on the threads, to aid later removal, before putting it in the plug hole. As always, never crank a plug tight with a socket wrench. Plugs on most cars and trucks should be torqued to about 20 foot-pounds.
I would not worry about deterioration of spark plugs over time, only mileage should be the gauge. They wear with use, not with time like rubber parts or something.
I went to the dealership for "Auxiliary Battery Malfunction" issue and at that visit, they told me I needed to have my spark plugs changed. I can't afford the $770 they want to charge so I want to do it myself.
I have seen some videos on youtube for the 2010-13 W212's and thought the process would be similar to my 2014 E350. However, after looking at my engine, I realized that I don't know how to take off the engine cover to gain access to the spark plugs.
Can anyone help me please? Thanks !!
You've probably done this already but here's a little video that explains the process
01-01-2018, 04:13 PM
Wrong again. Here is the scoop folks.
