I've changed the plug wires on a 93 400e and a 92 400SE - both have the M119 engine like yours. I agree with Deanyel, the job isn't that difficult, but depending on your DIY skill level can take a few hours to complete. On a scale of 1-5, I would give this job a 2. Neither car posed any unusual problems removing the plug wires from the boot or the distributor cap.

If you're a seasoned DIYer… my suggestions won't offer much help but if this is a 1st time working on the plugs of a M119 or similar ........

When possible, try to only work/change 1 plug wire and plug at a time. Pay special attention when routing the plug wire. Try and keep the same path and length of plug wire at routing points as you route each wire. This will insure the covers fit at the end of the job. Working only on one plug at a time will also keep you from attaching the plug wire to the wrong cylinder/plug.

On the M119 engine, you'll need a plug socket with a rubber insert that will hold the plug and a socket extension . You'll need the socket extension to reach the plug in the cylinder hole - this will become obvious when you look at the location of the plugs. Since the plugs are not accessable by hand, ALLWAYS screw the plug by hand, or in this case, holding the socket extension. This will prevent you from "cross threading" the plug. As Deanyel suggested, use anti-seize on the threads of the plug and dielectric grease on the plug boot. Follow the torque specifications and when completing final tightening of the plug and don't forget to check each plugs gap.

I also make special note of each "old" plug removed. Look for any unusual signs of plug wear or erosion. Problems identifed on the removed plug can give you insight into other problems regarding your engine.

One last note, do not use platinum plugs, use the Bosch Super - this what your MB was designed to use.

Hope this helps.

Russell

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Russell McMahon
Tulsa, OK
2001 CLK 320
1992 400se
1993 400e
2000 320ML