New Guy - 2009 E550 has melting plastic smell from heater vents
I have a 2009 E550 with about 98000 miles, have owned it about a year.
There is an odor that comes from the cabin heating/ventilation system that I first noticed several months ago. I took it to MB Service at the dealership where I bought the car a few times but I finally gave up on them as they seemed to be just guessing at the issue and generally giving me the run-around.
The odor comes from the heater vents, and smells like plastic that is hot but not burning; there is no smoke. If I put the blower to full speed the odor will soon dissipate, or become diluted sufficiently. If I set the fan speed back to a lower setting the odor will come back.
There are no oil leaks from the engine and I see no obvious sources of the smell in the engine compartment. At first I thought the smell was like hot oil, but it is actually more like hot melted paraffin wax, or melted plastic.
Has anyone got any ideas?
Thanks,
Steve
https://mbworld.org/forums/e-class-w...tic-smell.html
Mike T.

Seriously though... I have the same subtle odor issue... it's not bad enough to consider tearing my dash apart, but your information is intriguing.... does this foam coat the entire ducting or something like that... or does it just mask the smell? Where can I learn more about this option?
https://mbworld.org/forums/e-class-w...tic-smell.html
Mike T.
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The above vehicle models are not equipped with recirculated air filtering and biocide-coated evaporator. The following sequence of steps for eliminating odors in vehicles must be strictly adhered to:
- Identification of the cause of the odor with the aid of the diagnosis tree "Odor" from the Technology Guide "Vehicle Climate Control - Troubleshooting - Function - Design - Operation".
(The "Technology Guide - Vehicle Climate Control - Troubleshooting - Function - Design - Operation" is available in pdf format in SDmedia SDS).
If an odor problem still persists after all the possible causes of odor listed in the fault tree have been ruled out:
- Remove filter inspect it and replace it if it is saturated or clogged.
Note: The filter is a maintenance item and is not covered by warranty!
- Cleaning of the evaporator of the air conditioning system in the installed state using "Mercedes-Benz Contra Sept disinfectant cleaner". Further information on the cleaning procedure can be found in S-B-83.30/134.
- Cleaning of the interior using the "ultrasonic atomizer".
Remedy b): Model series 204, 172, 166, 212, 207, 218, 164 as of A407859, 251 as of A083326, 216 as of A012332, 221 as of A174161,
The above vehicle models are equipped with recirculated air filtering and biocide-coated evaporator. In these vehicle models the evaporator can be ruled out as the cause of the odor and cleaning the evaporator is not an appropriate remedial measure. As a result evaporator cleaning is not covered under warranty.
Complaints of odor can only be remedied by replacing the combination filter. The combination filter is a maintenance item and is not covered under warranty.
- It is recommended to replace the combination filter at every scheduled maintenance service at 10,000 miles or every 12 months, whichever occurs first.
- It is required to replace the combination filter at every scheduled maintenance service at 20,000 miles or 24 months, whichever occurs first.
you have a plastic burning smell, however I've heard and been told this dissipates majority of interior cabin smells.
Have you tried getting a car air purifier.... Heard those work in some occassions too.







