You'll save your engine in ways you wouldn't believe, having little to do with air filtration per se. Good for you!

 

The visible dirt doesn't have to make big flow restriction. It is the dust that you can't see with bare eye that clogs the filters.
Invest $10 on filter minder and not only you save fortune on good filters going to garbage but also will sleep better. I did it on older car and 100,000 miles in California still had the filter clean.
Now have to figure out where to tap the intake on 320 Bluetec.
I did the filters on OM642 twice and even I did it alone, I still think driver side is 2-men job.
There is no way you can push the left filter housing into the groomet from the top, while being under you have no way to pull it.
I used long screwdriver to guide the housing from down below and than give it push from the top.
For me the best way is:
- bolt driver side filter housing
-insert fresh air pipe (Moose) on the driver filter and turbo
-put the passenger side filter and till it to engage with fresh air pipe.
-once you wiggle everything and make sure the seals did not fold - you can torque the clamps.

 

 

 

 

Hmmm, when I do the filters I remove the power steering cap and oil cap, which give me a bit more room, as well as removing a bolt holding a harness on the passenger side.

 

Mercedes has gone nuts on the design of some of their air filters. A neighbor's wife had an ML with a diesel in it. My neighbor is normally a DIY type, but after puzzling over how to change the two air filters, and finding that he had to remove part of the firewall behind the engine, he sold the car instead and bought her an optioned out Ford Escape. They are both happy about it.

 

You were almost half way there when you had the "moose" out.
Probably a good idea to replace the two orange color seals (items 10 & 23) when you take it out for the fuel filter change.

 

Don't know about your neighbor and what year ML they had, but I changed mine several months back and had no problem. Did NOT remove any part of the firewall.

Where do these stories come from?

 

I think is WIS it actually suggests that? I cant imagine a tech would do that. I have it down to about 5 min a side to remove them because virtually any work requires they be taken out.

 

I can only speak for this story, and it came from my neighbor. It was an early second gen. model with a diesel engine. I suspect he was talking about the surround behind the engine rather than the actual firewall.

 

Hard to tell without seeing it, but I heard it on other forum that ML has part of the firewall design for easy removal, so you have better access to engine parts.
Other member used that for easy turbo removal.