Gents,

Some tips which will keep your HVAC water condensate at a lower level inside the HVAC box and less chance of mold growing and all the bad stuff associated with
lots of water for bacteria factory.

The process of blasting full blower speed of HVAC while compressor get turned OFF, say 2-3 minutes before arriving home is a good idea.
That will help to remove the water condensate from the evaporator core ALU fins.

However, do know that the shape of the HVAC box itself is not very good shape for natural gravity based water condensate evacuation when car is on level ground.

My house has 2 slopes, 1st one is quite a steep one from the road tarmac to my actual garage the level floor.
Usually I needed to wait like 20 seconds on the 1st hard slope to wait for the gate to open. The gate is manual, and my servant open it for me.
From the first hard slope near the gate, I will move forward to the softer slope of 1 car length before I enter the real in the building garage of 2 car length.

I have always notice that most of my HVAC water condensate would drain very well at the 1st hard slope at the gate.
I also notice when I do any test involving engine running ( HVAC always ON ), I will reverse my car to the 2nd soft slope and lots of water condensate will exit the HVAC housing/box.

So, if you guys have a soft slope before entering your regular parking spot, try to stay there 30 seconds and drain well the HVAC water condensate.
If you park on the side of the road with a slope , make sure the front of the car is the one at the higher end of the slope.

Here is a video I can show how just a few degrees angle change when I accelerated the car soft to HARD/WOT ( rear wheel suspension will sink under power ) , will cause the HVAC box to drain so nice and easy as
the front of the car is lifted up.
.


Hope this information can help reduce those smell some car owners are experiencing.

 

I wish they would have just designed it better.. No issues on my W211, but a search on 212s implies that every owner has the problem. I have done the cleaning procedures. The only thing that seems to help me is I leave the compressor on at all times now, even when using heat. Once it gets below 50, I'm blasting heat with windows and my sunroof open. Perhaps the combination of the dry air(compressor) and heat keep things clean, because it's rare that I smell the funky smell in the summer these days.

 

Yes, it seems some have smell issue. I don't have any and I am at 85% humidity at all time, so me location is bad bad bad.