Hi, guys!
New to the forum, but have been reading for years.
I could not find much information on replacing engine mounts in the w204 4matic models. I have a 2012 C300 4matic sport with 113k miles. I was starting to notice some slight vibration while in gear and at idle and not moving. So, this is a pretty classical problem of engine and transmission mounts that are worn or collapsed.

But, the problem was that I literally could not find any videos or tutorials for this particular car. So, I just dove right in! It is very similar to the w204 C63. This process on the c63 is actually pretty well documented. There are plenty of videos that show you how to do it.

So, in a nut shell:
1. Drop steering rack (can leave tie rods connected, but must remove the shaft that goes to the steering wheel). This will give you enough room to access the driver side mount. It is difficult to remove the heat shield, but it is doable. Also, there is enough room to take the mound out the bottom here. I would recommend removing the exhaust. It is not necessary, but will make your life easier.
2. Remove passenger side exhaust. This is essential to remove the heat shield on the engine mount on this side. It is absolutely impossible with it in there.
3. There is a heat shield around the drive shaft that goes to the front axle. I took this out so that I could remove the heat shield for the engine mount.
4. Remove the alternator. The only way the passenger mount can come out is through the front. This is where this job is different from the C63. The 4matic hardware does not allow you to get the passenger mount out the back/bottom of the car. This mount comes out the front / top.

There is not much room to lift the engine up. I was barely able to get the engine high enough to squeak the mounts out. I think something hits the firewall in back... not sure. My new mounts were OEM, but very hard to get in because you are limited on how high you can lift the engine. The old mounts were in tact, but worn enough to where they were shorter than the new ones. Therefore it was harder to get the new ones in. I ended up doing the driver side first. Then I had to set the engine down, and move the jack all the way to the passenger side. This way, I was able to get the passenger side of the engine just a little bit higher, which was enough to get the new mount in.

Basically, it is very similar to the C63 but with the differences I listed above. If you are thinking about doing this job you need the special 16mm Mercedes mount tool ($20), some very long 3/8 extensions and a swivel. So, nothing too crazy on the tool side.

So, sorry I didn't make a tutorial or nicer write up. My intention with the post was just to say that this job is possible on this car without removing the engine. At least when someone searches this topic, they will know this is not an impossible job. Just trying to spread some info!

 

Hi there,

Thanks for the write up on the engine mounts. I just wanted to add that the below thread has the part numbers for the M272/M276 engine/transmission mounts and the 16MM offset wrench:

https://mbworld.org/forums/c-class-w...ce-thread.html

 

Just about to tackle the motor mounts on my 2010 C300 so hopefully very similar to your 2012. Looks like I have a heat shield covering the mount and then also looks like the two bolts holding the mount to the subframe are removed from the top as well. Was that true for you as well?
Did you just loosen the steering rack or actually remove it?

 

The engine will lift higher with removal of mass airflow sensor and 90 degree elbow below...

 

Also, its not for a W204 but it is the identical procedure...