Replacing your Mercedes CLS550 W219 engine mounts can significantly reduce unwanted vibrations and noise, restoring a smoother and more comfortable driving experience. This guide provides a step-by-step process for removing and replacing the engine mounts on your CLS550 W219, focusing on a method that minimizes the need to remove unnecessary components. While this task can be accomplished by a DIY enthusiast, ensure you have basic mechanical knowledge and the right tools before starting.
Tools and Parts You’ll Need
Before you begin, gather all the necessary tools and parts to ensure a smooth and efficient process. For this engine mount replacement, you will require:
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New Engine Mounts: Corteco engine mounts are highly recommended as they are the OEM supplier for Mercedes-Benz. The part number you’ll need is 220 240 27 17 98 (Mercedes-Benz) or 601418 (Corteco). You can often find these mounts at competitive prices online, such as on Amazon. Some sources list Corteco part number 80001089 as a heavy-duty option, but they are likely very similar to the 601418. Decide if you want to reuse your existing dust shields or purchase new ones.
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Socket and Wrench Set: You’ll need a comprehensive set of sockets and wrenches, including 13mm, 16mm, and 18mm sizes.
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16mm Ratcheting Wrench: A 16mm ratcheting wrench is highly recommended, especially for accessing the top bolts of the engine mounts. While not strictly essential, it will significantly simplify the process.
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Car Ramps or Jack Stands: To safely access the underside of your vehicle, you’ll need car ramps or jack stands to raise the front end. Always prioritize safety and use appropriate supports.
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Wheel Chocks: Use wheel chocks to secure the rear wheels and prevent any accidental movement of the vehicle.
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Floor Jack and Wood Block: A floor jack is needed to carefully lift the engine. A small block of plywood or similar wood will be used to protect the oil pan when jacking.
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8mm Socket or Wrench: For removing the splash shields.
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Safety Gear: Always wear safety glasses and gloves when working on your car.
Step-by-Step Guide to Removing Engine Mounts
Follow these steps carefully to safely and effectively remove the engine mounts on your Mercedes CLS550 W219.
Step 1: Prepare the Vehicle and Disconnect Power
Begin by safely raising the front end of your Mercedes CLS550. You can use car ramps for an easier approach or securely position jack stands under the designated jacking points. Engage the parking brake firmly and place wheel chocks behind the rear wheels for added safety. Open the hood to access the engine bay. To prevent electrical hazards, disconnect the negative battery terminal cable. Alternatively, if you prefer not to disconnect the battery, carefully cover the rear of the alternator with a rag to prevent accidental arcing if your wrench touches the charging cable while working.
Step 2: Remove Air Intake and Covers
To gain better access to the engine mounts, you need to remove several components from the intake system. This includes the air intake system itself, the supercharger clutch pulley cover, and the air intake snorkels. These components are typically held in place by clips and screws and can be removed relatively easily. Consult your vehicle’s repair manual or online resources if you need detailed instructions for removing these specific parts, as procedures can vary slightly.
Step 3: Remove Splash Shields
Access the underside of your car and locate the middle and rear splash shields. These shields are usually secured by 8mm bolts. Remove all the 8mm bolts holding these shields in place and carefully detach the shields. Set them aside for reinstallation later.
Step 4: Detach Steering Rack Reinforcement Plate
The steering rack reinforcement plate, also known as the steering rack mount, needs to be removed to provide clearance for engine mount access. This plate is secured by four 18mm bolts. Crucially, these bolts are held in place by 18mm nuts on top, which are not easily visible from below. You will need to use a wrench to hold the nut on the top side while you loosen the bolt from underneath. This may require maneuvering a fixed wrench into position to securely grip the nut while you turn the bolt with another wrench or socket. Once all four bolts and nuts are removed, carefully detach the steering rack reinforcement plate.
Step 5: Reposition the Steering Rack
With the reinforcement plate removed, you can now gently pull the steering rack downwards and towards the front of the car. Moving the steering rack in this manner creates the additional space needed to effectively remove and install the engine mounts. It’s important to do this carefully to avoid stressing any steering components.
Step 6: Unbolt Lower Passenger Side Engine Mount
Locate the lower bolt on the passenger side engine mount. This bolt is a 13mm bolt and is generally easy to access. Use your 13mm socket or wrench to unbolt and completely remove this lower engine mount bolt.
Step 7: Jack Up the Engine Slightly (Passenger Side)
Position your floor jack under the rear portion of the engine oil pan. To protect the oil pan from direct metal-on-metal contact and potential damage, place a small block of plywood between the jack and the oil pan. Carefully begin to jack up the engine, but only raise it by about half an inch initially. Ensure that the wood block is positioned so it does not press against the rear oil drain plug. Lifting the engine slightly at this stage relieves tension on the top engine mount bolt, making its removal easier.
Step 8: Remove Top Passenger Side Engine Mount Bolt
Now, using your 16mm ratcheting wrench or a standard 16mm wrench, access the top bolt of the passenger side engine mount. The best approach is typically from the top and front of the car. Space is limited, but with patience and the ratcheting wrench (if you have one), you should be able to get enough leverage to loosen the bolt. Once loosened, fully remove the top bolt. After removing the bolt, you can also easily remove the heat shield that sits behind the mount; keep this aside for reinstallation.
Step 9: Raise Engine Further and Remove Passenger Mount
With the top bolt removed, continue to carefully jack up the engine another 2-3 inches. Raising the engine further provides the necessary clearance to maneuver the old engine mount out. Don’t be concerned; lifting the engine by this amount should not cause any damage to surrounding components. Once you have sufficient clearance, remove the old passenger side engine mount. The mount can be removed through the lower front section of the car, between the sway bar and the steering rack. It’s a tight fit, but it will come out with some careful maneuvering.
Step 10: Install New Passenger Side Mount
Installation is essentially the reverse of removal. Decide whether to use a new rubber dust cover or reuse your original one if it’s still in good condition. When maneuvering the new mount into place, make sure the tang on the new mount aligns correctly with the mounting boss on the engine. This ensures proper positioning and fitment.
Step 11: Reinstall Passenger Side Bolts and Lower Engine
Reinstall and tighten the lower 13mm engine mount bolt. Then, carefully and slowly lower the engine back into its original position using the floor jack. As you lower the engine, double-check that the mounting boss aligns correctly with the tang on the engine mount. Reinstall the heat shield and then reinstall and tighten the top 16mm bolt.
Step 12: Repeat for Driver’s Side Engine Mount
The driver’s side engine mount is removed and replaced using the same procedure as the passenger side (steps #6 through #11).
Driver’s Side Notes: Accessing the top bolt on the driver’s side can be slightly more challenging. Approaching it from the same angle as the passenger side (top and front of the car) is usually the most effective. Due to space constraints and potential interference from the heat shield, a fixed 16mm wrench might be necessary to loosen and remove the top bolt on the driver’s side, as a ratcheting wrench may not fit. For removing the old driver’s side mount and installing the new one, the same technique of maneuvering it through the gap between the sway bar and steering rack can be used. However, because the new mount is not compressed like the old, failed one, you might find it helpful to slide the new mount up from the passenger side and then snake it across to the driver’s side, passing between the steering rack and the front of the oil pan.
Step 13: Reassemble and Final Checks
Once both engine mounts have been replaced, reinstall all the components in reverse order of removal. This includes:
- Reinstalling the steering rack reinforcement plate and tightening the 18mm bolts and nuts.
- Reinstalling the middle and rear splash shields using the 8mm bolts.
- Reinstalling the air intake system, supercharger clutch pulley cover, and air intake snorkels.
- Reconnecting the negative battery terminal cable (if disconnected) or removing the rag from the alternator.
Lower the vehicle from the ramps or jack stands. Start the engine and check for any unusual noises or vibrations. Take a short test drive to ensure the new engine mounts have effectively resolved the original issues and that your Mercedes CLS550 W219 is running smoothly.
Disclaimer: This guide is for informational purposes only and intended for experienced DIYers. If you are not comfortable performing this procedure, it is highly recommended to seek professional assistance from a qualified mechanic. Incorrect installation can lead to damage or safety issues. Always prioritize safety when working on your vehicle.
