(note - attachment is the WIS for this work).

A while ago we replaced the belt drive components and later (which I did not write up about) the transmission mount and flex discs on our 2003 E320 - all to great success. Car ran great and smooth - time well spent.

https://mbworld.org/forums/e-class-w...ft-pulley.html

Since then over a rather short period of city and highway driving - under 10k miles - a new vibration has started that is very slowly increasing in intensity. Everything pointed to those motor mounts that I thought were still in good shape - so time to replace them. I ended up using the Corteco mounts from fcpeuro.com

Like others have written up - I also ignored the WIS and removed the alternator to give access to the passenger side mount (don't forget to remove that battery negative first!). For access to the drivers side I removed the steering linkage (single 13mm head bolt), removed the left side exhaust from the flange (two 13mm head bolts) and the two 13mm nuts securing it to the transmission and just let it hang down 2 inches or so. Combined giving you all the room to you need to remove the drivers side mount from under the car.

I'm doing this in my garage with the front on ramps and to live the engine off the mounts just a floor jack with a small 2x4 under the oil pan to lift the engine the 1-1/2" needed to remove the mounts.



Other than finding the top motor mount 16mm head bolts don't have much clearance to both remove and install there was not anything significant about the job. I did replace both at the same time - I could not see any reason to not do both even though others have written the did one at at time - that just seems like extra work to me to. About the only thing I want to make sure folks don't forget is there is an orientation to the motor mounts. The have a tab on the top and that tab MUST align with the female slot on the engine mount bracket. The easiest way I found to do that was to put the mount in place and insert the bottom bolts and just tighten a couple of turns to hold the mount in place but allowing you to turn it. Then align the mount so it is in line with the bracket. Once you have the alignment, slowly lower the engine. I also found screwing in the top bolts required me to not have all the weight on the mount - so lets say I ended up with some weight still on the jack allowing the threads of the top bolts to align and catch.

There are two shields protecting the motor mounts - they are installed on the top of the bracket with the same 16mm head bolt holding it in place. These have a left and right - make sure to get the correct one back in its place. ALSO they have a tab slot that aligns it correctly with the motor mount bracket, make sure it is aligned up. It may seem a bit frustrating getting it aligned correctly, and getting that top bolt installed in the limited space between it and the the manifold but the bolt DOES fit - just play with it. Take your time and make sure that shield is aligned correctly.

I have attached the WIS for this and it has some good pictures on the correct alignment.

Here is the old and new mounts.


Here is a closeup of the drivers side - the entire top of the mount is split.

I replaced my bottom bolts when I did this since they were only a few bucks on fcpeuro but the ones I pulled out were perfectly fine. Still I would replace them - they are low cost enough to not matter.

Final note. Some will say you don't need that special tool to do this - it is a short 16mm slightly offset stubby wrench. Ignore them. The tool is low cost and without it I can't see any possible way to properly torque the top nuts. If you have a 24" 3/8" extension it makes this really easy. Here is my setup just getting ready to torque them.


And now that new vibration is gone - car runs smooth.

Useful torques:

Steering shaft 13mm head bolt(1): 20NM
Exhaust flange 13mm head bolts(2): 20NM
Exhaust flange 13mm nuts(2): 20NM
Alternator bolts - E14 bolts(2): 45NM
Bottom motor mount 13mm head bolts(2): 35NM
Top motor mount 16mm head bolts(2): 55NM

Tip: For the exhaust flange bolts, coat them in a high temp anti-seize in case you need to remove them in the future - will make yours or the next persons life much easier. I use MRO 2400 which I have had a jar for many years but any high temp anti-seize will work.

 

Nicely done! Thank you for the tips!

 

Ha! I am such a sucker when it comes to “special tools”. I love them, and in my past life, made them for machines I designed.

Peter

Btw, the tool should be 90 degrees to the torque wrench so you don’t add moment arm to the torque. Fo example, if the tool was six feet long and you had it long wise, you would greatly overtighten the bolt.