ArcticE

Hey, I have read all of the posts on this forum about the A/C smell problem and ways to solve it and I just bought a can of lysol to try the lysol treatment. I went to do the job today and the picture from the "how to" I found does not match with my 2010 E-350 for the vent to spray the lysol in. I took a few pictures of the different spots on my car and I was wondering if any of you could confirm the correct place to spray the can into.

Here are the different spots:

1. Airbox removed above battery, spray in right side opening?


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2. Large vent below windshield wipers that shows even when hood is closed?


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3. small vent in passenger and driver's side corners of black plastic below windshield wipers?


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Thanks for any help and any tips on doing the job would be appreciated.

thefisch

I may be wrong but the it looks like the the air recirculator is on since the flap on the left side in the first pic is closed. From what I recall reading, you would spray into the left side. Is Lysol recommended for this? I thought it was preferred to use frigi-fresh or some other non-corrosive spay. But maybe Lysol is safe on metal.

SnakeDoctor

I only ever tried putting on recirculation and sprayed some spray (forgot which one) in the footwells of the car. It helps, but ultimately it just masked the smell. During service, when the filter was changed, the smell was gone.

Let us know how this works for you.

ArcticE

Yeah, I was wondering why that flap was closed in the left side opening while the recirc was supposed to be off...I then pressed the recirc button on and off a few times while the car was running and it did not move the flap. Could it be broken and maybe the reason for the bad smell in the first place?

thefisch

if the recirc is on all the time then that would be an issue as you are not bringing in any fresh air which is important for moisture control and oxygen/CO levels. You should able to tell while driving if the recirc is able to toggle the flap. You can usually tell the difference in the airflow and also the difference in the smell of outside air.

I didn't take any photos, but the last time I took off the air box (to check the battery) the recirc flap was down and you could see the fan in the opening to the left. Did you turn off recirc before shutting off the car and removing the air box? I haven't done this when the car is running to know if the car can sense the air box is not in place and close the flap automatically.

ArcticE

Yeah, I'm pretty sure the recirc was off as I believe you need to manually turn it on and the little light goes on in the switch as well. I read in the owners manual that you can hold down the recirc switch while off and it should close all of your windows/sunroof and turn on and also open all windows and turn off when held again. I will be doing this tomorrow and checking the flap to see if it ever opens and I will post my results. Thanks for the feedback so far.

belarus27

I thought that option doesnt work on w212 , it doesnt close/open windows just like it did on w211. Correct me if im wrong. 😊

thefisch

Not wrong.

ArcticE

A couple things:

1. You guys are right and holding down the air recirc button does nothing.

2. The flap that opens and closes in the air box is not broken in my car as I was able to see it working by having the car blowing fresh air and then pressing the air recirc button or a/c button.

I now have a new question. Since pressing the a/c button closes the flap in the air box, how are you supposed to spray anything in there to get it to circulate through the a/c system? I tried every combination of pressing the air recirculation switch/a/c switch/max a/c switch and I was never able to have the a/c on with the flap open.

mleskovar

I'm thinking that you have the climate control mode in Automatic and the reason the Recirc flap is closed is because the system senses the cabin air needing rapid cooling off? If you haven't done so yet first change the cabin filter.....that's usually the major mold collection point.

ArcticE

Ill check if it's on auto and get back to you. As for the cabin filter, I replaced it about a month ago.

thefisch

I am not certain that you need to have the AC on for the cleaning process. The important part is for the spray to be distributed while the blower in on high. I would go manual on the climate control with the fan cranked all the way. It's up to you if AC is on or not. Either way, the spray is being carried over all the same parts (i.e. ductwork, filter, coils, etc.).

Live Oak

Arctic, I don't know where you stand with this right now, but every time you park your car, after about 45 mins to an hour the AC fan should start up, quietly, on its own and run for about an hour. That's to dry the AC evaporator. The whole idea is to prevent any mold-like smell. With all the crap now in engine compartments and dashes, things are so tight that the evaporator won't dry properly without help.

It's possible for the MB techs to accidentally turn the fan drying cycle off when screwing with your software. It happened to me, and I started getting "dirty wet foot" smell. After they re-enabled the drying cycle the problem went away. And I'm in the desert!!

Also, there is a drain to direct any water from the evaporator out on the road/driveway.

So if you are having smell problems, it might be worth your while to listen for that fan cycle in your garage (it's very quiet, outside at the passenger side) to make sure it's working, and to be sure you see some water on the floor after parking on a hot, humid day with the AC running.

I suppose if you are in Florida, the drying cycle might not be enough, but it doesn't look like you are there.

ArcticE

Thanks Liveoak, I will be checking that fan to make sure it does go on. As for the spray, I ended up spraying into the left side opening with the fan on high and the flap open. It definitely went through the car and I let the fan blow with the windows down for about 15 minutes after. I will give an update in a few weeks about if it solved the problem. Thanks for all the comments.

thefisch

Thanks for the tip, I am going to check that also. So if you don't hear the fan, the next step is to take it to service and ask them to check and see if the 'fan drying cycle' is enabled. Is that what it's specifically called?

BenzV12

I have read at the various car mags suggesting you should let your car run 5 mins or so and then turn off A/C to prevent some unwanted odors in long term or bacteria generation

aeroconfigs

I changed my filter about a year ago and the smell is back this year. Maybe I'll try the Lysol when I do a new filter.

thefisch

So did the treatment with Lysol make a difference right away? Also, what was the original smell?

I tend to get a musty smell that is slight rotten/sweet. From the AC vents that is.

By the way, no fan ever came on for me after running the AC all the way home. Checked 45 minutes and 1 hour after. Maybe I should have checked sooner?

thefisch

How would you describe the smell? Did the old filter reek when you took it out a year ago? If the filter didn't smell, I wonder if the new filter just masked the source of the odor that remained.

pdjv

Sounds like the automatic "REST" function isn't working - that's supposed to come on a short time after the car is turned off to operate the HVAC fan and dry the system to prevent odors.

There was a problem with the automatic REST on some cars - the fan wouldn't shut off after the programmed normal run time and would drain the car's battery. IIRC, there was a TSB and a dealer-applied fix.

thefisch

I thought I read that feature had to do with residual heat and didn't come on the US models.

pdjv

Yes and no. Cars that have a "REST" button can use it to circulate warm air when the car is shut off, but it will also dry residual moisture in the HVAC system.

U.S. models don't have a REST button so there's no way to use residual heat to keep the car warm after it's shut off. U.S. models get an automated system that switches the HVAC fan on about an hour after the smart key is removed. The HVAC fan will run at low speed for about 30 minutes to dry the system.

So, while U.S. models don't have a REST switch, they do have a REST function.

ArcticE

UPDATE:

So far so good.

To recap: The smell I originally had was a musty/moldy smell that came through the vents for the first minute when I turned on my a/c. I had already replaced the cabin filter and the smell did not go away. I bought a can of regular lysol and removed the air box as shown in the first picture. I turned the fan on to high with the a/c off so that the flap in the left side of the air box space (1st pic) stayed open. I then opened all windows and roof and sprayed the lysol into the opening for about 1 minute continuously. I left the car on for about 15 minutes after and half way through those 15 minutes, turned on the a/c to get the spray to blow through that system as well (not sure if it's a different system but couldn't hurt). Also do not breath in the lysol or have anybody in the vehicle until all of the spray has dissipated. When done, re-attach the air box above the battery.

So far the smell is gone and every time I start the a/c I smell a hint of lysol and that is it. I hope this works for the long term but even if it is something I have to do once a year that's fine with me.

Thanks for all the feedback and if any of you get the smell might as well give it a try.

SnakeDoctor

Good stuff. Keep us posted, and I'll most certainly have to keep this in mind and do it myself!

Thanks ArcticE

jygesq

a few minutes before you shut off car, you should not get the smell returning.