W166 Airmatic filter replacement
 

I have a 2013 ML 550 with Airmatic. I figure at 50k miles, it is due for the intake air filter replacement for the airmatic compressor. Looking online, there are a few instructions on replacing these for other models, but not my W166. I think my compressor is in the rear of the vehicle from the sound, not the front as shown in the available videos. Does anyone know where the filter is located, and how to get to it?

Driver side, far interior corner
 

FOUND IT! The pump is located under a hidden hatch in the far left rear corner (drivers side) just below the subwoofer in the floor. It is covered in high density foam. The pump in the W166 has no intake filter! Probably because it is in the car interior, under a hatch, covered in foam, so it isnt dusty down there.

So there are TWO airpumps! One in the rear, and another one on the right/passenger side behind the front bumper down low. To replace the front pump filter (MANN 32/7), take the right wheel off, take off the wheel well liner (2 plastic nuts, 3 plastic push rivots, and 4 small bolts under the spoiler), remove the 3 air compressor nuts to get it out of the way, then there are 2 spring clips holding the Mann 32/7 filter into its housing (user pliers to squeeze them open). There is a rubber housing/shroud covering 3/4 of the filter that is sort of a pain to get the old filter out of and the new filter in. I blew the snorkel line out with compressed air. It is a rubber tube from the filter up into the fender well. Mine was 9.5 years old, 62k miles, and it wasn't looking all that bad. Little dirty, but air still flowed thru just fine. These could probably last 100k miles or 15 years...I'm thinking.

Never heard of changing the airmatic filter....

I firmly believe ALL filters have to be replaced at some point. They all clog up eventually, and the filter elements just get old and brittle (usually paper fiber) and can introduce their own contaminants. You definitely dont want dirt and debris getting into the pump and airmatic tubing and valves.

Most people just replace the filter when they replace the compressor. Haha.

same here, and i havent seen it on any of the scheduled maintenance lists from the Mercedes documents.

maybe they dont count it as a maintenance item and only replace it when there is a failure.