Need some valve cover info
 

2013 C63 P31. I found a leak coming from my valve cover and bought all the necessary replacement parts for a weekend DIY (2 Rubber Gasket, 8 rubber seals for the ignition coils and 26 new valve cover bolts). My friend works for a shop that works on mostly Euros, not Mercedes specialized, strongly urged me to bring it to his shop because, "the valve cover for the FL model c63 puts pressure on the camshaft and if you don't take it off and put it on properly with special tools, you'll mess up your cams, cylinders, etc." This is the first i'm hearing of this. From everything I've read, I thought all I gotta do is pull up the air box, remove ignition coils, move some tubes out the way, take off the bolts, take off the cover, replace the gaskets, hand tighten the bolts to 8.5 Nm and reverse, nothing special. Never read anything telling me to do anything special or pay any extra attention to the cams. Now..... is my friend trying to scare me away from a DIY and bsing me to get business for his shop? or am I the one who didnt have enough info?

The M156 doesn't require anything special to do the job.. The M157/M278 is the upper cam bearing (on the valve cover itself), but with those they don't have gaskets, they are sealed to the cylinder head with sealant and very rarely leak.

The procedure is as you described, nothing more except to clean the surface before installing the new gaskets.

woah, super quick response lol thanks guys for helping me confirm!

Super simple job, just somewhat of a pain to seat the gasket properly while sliding the valve cover under the wire loom particularly on the drivers side towards the firewall.

When I replaced the gasket in my E55, I put a very small amount of MB sealant between the gasket and valve cover (in the gasket groove) to prevent the gasket from falling. I don't know if this correct or not, but it did the job.