How can you tell if your Mercedes needs new motor mounts? Well…
I did this simple test by opening the hood, starting the car and putting it in drive. While holding the brake, give it a little gas until the engine starts to torque over. If your driver’s side mount is completely separated like mine, it will be obvious. I thought the engine was going to jump right out of the car!
The M113 and M113K motors in the AMG Mercedes are notorious for destroying engine mounts because they make a lot of torque. Replacing CLK engine mounts is not hard, but it does take a lot of patience, and one special tool. My car happens to be a CLK55 AMG, but this DIY is applicable to the 1998-2002 CLK320 or CLK430 as well. Read-on if you want to learn how to do this job and save yourself about $500 compared to what the dealer would charge you.
Here’s what the old, dead driver’s side mount looked like (right) compared to the new one (left). At one time it was a fluid-filled hydraulic engineering masterpiece, but now it’s a crusty old dried-up broken shell of its former self. The passenger side was still in one piece, but it was leaking fluid. It’s always best to replace them in pairs anyway, as they are very common to fail.
Upgrade to E55 Engine Mounts
I accidentally ordered a pair of motor mounts for a W211 chassis E55 instead of the W208 CLK55! They bolted right in, and honestly, I didn’t even realize I ordered the wrong part until I sat here writing this article. I figure since they bolted right in, and they are designed for the 516 ft-lb beast in the E55, they should be sufficient for the NA M113 in the CLK. I used Lemförder mounts because they are an OEM quality piece at a much better price. There are cheaper alternatives too, but Lemförder is a brand I have used in the past and I trust them.
What you’ll need for this job
Follow these links to purchase the items needed for this project:
- 8 mm Socket
- 13 mm Socket
- Mercedes engine mount tool (16 mm)
- Various 3/8″ extensions
- 3/8″ U-joint (optional)
- Floor Jack
- 2×4 scraps
- Patience getting the top bolts out!
Let’s Get Started!
The first thing to know about this job is that getting the top bolt off the engine mount is a real pain in the ass! I find it best to get the car up on ramps or jackstands and remove the four 8mm bolts that hold on the belly pan. Be sure to disconnect the main battery, as you will be working in close proximity to the power wire on the back of the alternator. Then lay on the ground and look up near the exhaust manifold on the front side of the engine. Reach up there and feel for the top motor mount bolt. It’s a 16mm and you will definitely want to use the special Mercedes engine mount tool to loosen it. If you look closely in this picture you can see the tool peeking out from behind the heat shield.
Here you can see the train of 3/8″ extensions I assembled to reach the tool. You’ll probably want to use a 1/2″ ratchet and adapter so you can get enough torque on the bolt to loosen it. Using the engine mount tool allows you to reach the bolt, but it also reduces the torque you are transmitting to it, so a longer ratchet helps. Be sure to set your ratchet to “tighten mode” because you are coming at the bolt from underneath, so you want to turn it clockwise from this perspective to loosen it.
After you have removed the top bolt on each mount, you should get a couple pieces of 2×4 and a jack under the oil pan so it can support the weight of the engine. Once the jack is in place, remove the two remaining bottom bolts using a 13mm socket and an extension, then proceed to jack the engine up 2 or 3″. The mounts should be easy to remove at this point.
Installing CLK Engine Mounts
When installing the new mounts, remember that the old mounts were probably collapsed, so you may need to jack the engine up higher before putting them in. Make sure the prong on top of each mount is inside the groove of the engine bracket and hand-tighten the top bolts. Slowly lower the engine down so it is just shy of sitting on the subframe. This will allow some wiggle-room to get the bottom bolts started before you completely lower the engine. Then it’s just a matter of tightening all four bolts and reinstalling the belly pan and you’re done. Congratulations, you just saved $500 that you can now go spend on race parts!