Motor mount replacement 1999 W210 - 5.5 liter engine
05-16-2014, 10:50 PM
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'99 and '05 E55 AMG
Motor mount replacement 1999 W210 - 5.5 liter engine
This explains how I replaced the motor mounts on my E55. Remember, safety first! Disconnect the battery or, as I did, place several layers of duct tape over the back of the alternator and the front of the starter to ensure one does not accidently short the battery lead to ground. Bad things happen if one shorts the battery to ground!
When examining my newly purchased E55, I noted that the underside of the motor mount bracket was apparently “splashed” with some liquid that later dried. Further investigation indicated this was indicative of a bad motor mount.
Car securely placed on jackstands, piece of wood on top of the floor jack placed under the oil pan and engine raised to release pressure on the motor mounts. I started on the passenger side, removed the lower engine mount bolt (easy) and then attempted to remove the 16mm bolt on the upper side of the mount. I used a ratcheting wrench (no luck), then a standard combination wrench (no luck), attempted to put a socket on it (no luck). I just could not get enough leverage to break the bolt loose. I finally removed the bracket from the engine block, placed it in a vise, and could finally break the 16mm bolt loose. Be advised the bracket's upper rear bolt was the most difficult to remove. I ended up reaching it from behind the steering mechanism with much descriptive language and many scratches to my forearms. The other three bolts were relatively (compared to the upper rear!) easy to remove. Remember, these bolts are 12mm Torx-head, not hex-head. Be advised that when I pulled the bracket and mount out, the remaining oil in the motor mount poured out of the break in the rubber and covered me in oil. Expect it.
Reinstalled the bracket, then the motor mount (be sure to align the tab!) with the upper bolt, and then lowered the motor enough to install the lower bolt. Passenger side complete! After 1 ½ hours…<grumble, grumble>.
On to the driver’s side…uh, oh. No way I was going to remove the bracket on that side. Other stuff (AC compressor) bolted to it. That’s a lot more stuff to remove. I decided to give it a try and the upper bolt broke free on the first attempt! Seems the motor mount was replaced previously. I replaced the mount with a new mount anyway and tightened the upper bolt as best I could.
Uppermounts should reportedly be 55 N-m, lower mounts 25 N-m. Upper mount was tightened as best I could with the wrenches I had. The lower mount was good-to-go with a torque wrench.
When examining my newly purchased E55, I noted that the underside of the motor mount bracket was apparently “splashed” with some liquid that later dried. Further investigation indicated this was indicative of a bad motor mount.
Car securely placed on jackstands, piece of wood on top of the floor jack placed under the oil pan and engine raised to release pressure on the motor mounts. I started on the passenger side, removed the lower engine mount bolt (easy) and then attempted to remove the 16mm bolt on the upper side of the mount. I used a ratcheting wrench (no luck), then a standard combination wrench (no luck), attempted to put a socket on it (no luck). I just could not get enough leverage to break the bolt loose. I finally removed the bracket from the engine block, placed it in a vise, and could finally break the 16mm bolt loose. Be advised the bracket's upper rear bolt was the most difficult to remove. I ended up reaching it from behind the steering mechanism with much descriptive language and many scratches to my forearms. The other three bolts were relatively (compared to the upper rear!) easy to remove. Remember, these bolts are 12mm Torx-head, not hex-head. Be advised that when I pulled the bracket and mount out, the remaining oil in the motor mount poured out of the break in the rubber and covered me in oil. Expect it.
Reinstalled the bracket, then the motor mount (be sure to align the tab!) with the upper bolt, and then lowered the motor enough to install the lower bolt. Passenger side complete! After 1 ½ hours…<grumble, grumble>.
On to the driver’s side…uh, oh. No way I was going to remove the bracket on that side. Other stuff (AC compressor) bolted to it. That’s a lot more stuff to remove. I decided to give it a try and the upper bolt broke free on the first attempt! Seems the motor mount was replaced previously. I replaced the mount with a new mount anyway and tightened the upper bolt as best I could.
Uppermounts should reportedly be 55 N-m, lower mounts 25 N-m. Upper mount was tightened as best I could with the wrenches I had. The lower mount was good-to-go with a torque wrench.
Last edited by bbirdwell; 05-18-2014 at 12:25 PM. Reason: clarification
