On my 2013 E350 4-Matic, I found almost nothing on changing the spark plugs except a lot of wrong information. People could not get the covers off, people would offer to help showing engines before 2012 and say it's easy. Places Like All-data show you great pictures...just not on the correct engine. So I have been keeping good notes and pictures to post for many who will want to do this. I have done this the long way, as the cover we all refer to on the engine is actually the manifold. You do not have to remove it to do this, but I assure you, it is a lot easier, and give's you good pics.

The two pieces I have questions about is the sequential torquing of the spark plugs AND

Do I really have to replace the manifold gaskets.

I normally put on a little bit of anti-seze. If I do that, will the plug not line up correctly?

I am using a regular 14mm 12 pt socket, that is not a "Spark Plug" socket, will that affect the torque?

I took one of the plugs out to re-check it, since the specks talk about it aligning up correctly, did I just waste this plug?

There are no tears in the neoprene seals, any reason I cannot put a little rtv on them?

 

No need to replace the manifold gaskets and bit of anti-sieze won't hurt either. It's recommended that you apply connector grease 002 989 80 51 to the coil boot - NOT RTV! Not sure what you're referring to when you say "sequential torquing". The spec is 23nm. The use of a standard 14mm socket won't effect torque - but without the rubber boot - make sure to keep the socket very straight on the plug to keep zero lateral load against the insulator. And - aligning up correctly? Again - you can only thread the plug in the standard way. There are no other concerns.

 

Don't overthink it too much, just torque them to spec and have at it.

We reuse the manifold gaskets at times, just remove them from the manifold and fit them on the lower half, so they don't get torn during install. No RTV needed.

I always put a little anti-seize on the plugs and the coil grease in the boot.

As far as the alignment angle, we've marked the sockets and aligned the electrode, then tightened them under/over spec, the difference is so minor, it can't matter. Same with re-using plugs, makes zero difference.