Changing the Cabin Air Filter

The W140's use filters to clean the cabin air for your comfort. The S600 actually has three filters all together. There is the pollen filter (some with and some without an activated charcoal layer), the activated charcoal filter, and the cabin recirculation air filter. The pollen filter is located directly above the blower motor under the hood. The activated charcoal filter is buried deep in an area near the base of the windshield. The recirc filter in located under the front passenger knee bolster.

MB recommends that the pollen filter be changed every 60,000 miles. The activated charcoal filter does not usually need to be changed unless you smell musty or bad odors when the climate control is in recirc mode. The recirc filter should probably also be changed every 60,000 miles.

Tools needed:

• Phillips screwdriver.
• Small flat blade screwdriver.

Remove the 6 Philips screws holding the entire plastic assembly down. You will be removing this whole assembly. One screw is on the driver side, the other five are towards the passenger side.
Once the screws are removed, lift the driver side up slightly to gain access to the air temp sensor and hose fitting.
Twist the hose fitting clockwise (when viewed from the top) to disengage the locking tabs holding it in place. The air temp sensor should pull straight out.
Now you can remove the whole assembly from the car. Lift straight up and out.
This is where the filter goes, directly above the blower motor. The filter is removed in this picture. Be careful when removing the filter, there may be a good amount of debris on it. We don't want it falling into the blower assembly. While you have access to the blower, make sure it spins freely. If it does not, place a few small drops of electric motor oil on the blower bearing and shaft. Note: I removed the entire vacuum motor from the assembly in this shot. You do not need to do this, simply remove the hose from the vacuum motor.
Here's a shot of the old filter next to the new one. The old one was very dirty.
Underside of the new filter showing the charcoal layer. Give the new filter a little shake to dislodge any loose bits of charcoal. You don't want this falling into the blower assembly.
You may want to check your brake fluid level at this time. The cap of the master cylinder is in a bad place, and it's difficult to add fluid with the assembly in place.
Make sure the rubber lip on the new filter is seated in it's mating groove properly when installing it.
You should also check to see if there is any debris in the rubber drain hose coming off the bottom of the assembly. It is on the filter side. If it is clogged, clean it out. This is how water drains out of this assembly.	Sorry, no photo available.
You're ready to put it all back together now. Reverse the steps listed. Make sure the drain hose is not kinked when re-installing the assembly. Well done!

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