I started the day of work at about noon. It was a breezey day, around 75 degrees with partly cloudy skies. I opened the hood, proped it to service position, and off I went. A journey into the engineering of Mercedes-Benz, looking at all of the german writing bill-board's along the way lol.

I took off the filter box, that was easy.

Next I started to work on the coil overs. My plastic was brittle after 94,000 miles in the Florida Sun and Sand, so a couple of plastic tabs snapped. Nothing major, the plugs fit snug with or without the tabs. Anyways, I also took a air compressor and dusted out the work area prior to my journey.

Next, the hardest part of the complete install. Getting the damn boots to let go of the plug! I didn't have the mercedes tool, so I gorilla tooled a wrench and used the manifold as the center of my see-saw of torque. Worked Great!

The plugs were on their pretty snug too, but anyone with experience changing spark plugs knows what they are getting into when they start. It is not easy, but it is not hard by any means. There is no techinical brain power required other than to remember to set your coils out in the same pattern you removed them so you don't put them in wrong order. I don't know if it matters if you do or not, but I chose to keep them in the same place.

WARNING! The coils can contain energy after being disconnected. Don't let them ground out!

I finished up by 5:30, changing 11 out of 12 plugs. I couldn't use my pongo-pigmaise fashioned socket system to get in between the heat shields and the plug. It's just too small.. There's a non-dealer shop local here I will take it to, to change that last spark plug. He's honest so I know he'll do it.

So far, I have noticed a HUGE difference.. However, my other plugs were the originals with the vehicle. so I would say I gained back more horsepower lost, than actual horse power gained past factory spec. The difference was very appearent in the cool night air on the freeway. When I got onto the freeway, I caught up with traffic a little faster than what I'm used to. Also, the initial throw into your seat upon take off is a little stronger, along with throttle response being slightly better.


OVERALL, The plugs were worth it 10x for me.. I'm not taking my car back to the dealer anymore, I'm going to do everything myself or pay third party shops. I have the 100k transmission service comming up, which from what I read here is nothing more than a filter change and a flush. I also ordered the computer reset StarDiag unit that way I don't have the annoying red screen of death flash at me when I know my oil is freshly changed. The money i've spent at the dealer, can be spent in better products such as the following:


Next Mod due before Christmas, Evosport Pulley's and KN Filters

 

Good job , nice write-up.

 

Nice writeup! I just changed the plugs on my parents ML430 this past weekend and that was a major PITA! There is absolutely no room on the drivers side. Passenger side took about an hour, drivers took about 2. Try 16 plugs for that V8 Some battle wounds on my arms but they're healing.

As far as the boots, I'm not sure if its the same on the 2.6L, but for the MLs, its recommended that you use an open ended 17mm wrench and use the engine block as a leverage to loosen the boot. Sounds like you used the same method.

 

Did you experience the same performance results ?

 

The car idled smoother, the exhaust immediately sounded deeper. Before, revving the engine produced a "whining" sound but with the new plugs, it sounds like a mean V8, nice deep growl to it.

Performance wise, its smoother acceleration, no hesitation and peppier.