Ellacino

Hi for some time I've had an issue with smelly aircon on my ML.

No problems if started from cold but on restart there is an awful musty doggy smell from the aircon. It clears after a few minutes.

MB have had it back and have cleaned the evaporator by a couple of methods, changed the cabin filter, deodorised etc but it always comes back.

Not sure if it's related but it never drops water from the aircon like every other brand of car I've ever had. MB says the drain has a deliberate restriction and the engine has to be running to blow the water out, even then I've never seen anything. They say they've checked it and it's ok.

My gut feel is that it's water related, maybe stagnating somewhere.

Any help or experience would be gratefully received

350MH83

This is a very common problem with MB. It affects more than just the ML, most models can have it. I had it on my ML350 BT (2013). I dont have it (at least not yet) on my 2017 GLS.

Ellacino

Hi,
Thanks for that, did MB or you ever resolve it ?

350MH83

I got the AC sprayed with some chemicals once by an MB dealer. They had an advertisement on the front door specifically for this thing to treat smelly AC systems, so I guess I wasnt the only one complaining about it. It made things better, after some months I think I was able to smell it again sometimes but at a lower level. Then I totalled the car so never got the issue again Maybe with a couple more months it would have come back to the same level.

Ellacino

Can you remember if you ever saw water under your car from the air conditioning, we never do. Every other car I've ever had drops water from the aircon. Australia gets pretty hot and I think that the problem is more noticeable in the summer and will lessen now it's Autumn. Perhaps the problem isn't as pronounced in Europe.

350MH83

I dont reckon having seen a puddle of water under my car. But I believe I have seen water drips, just not enough to form a puddle. As you say, maybe there is a system that prevents the system from draining while the car is stopped.

easyedwin

Splash guard under engine prevents floor spotting.
Spray Lysol onto the air intake at the bonnet [hood].

DanD.

I saw a lot of videos on youtube
Like this one People use steam cleaner for air vents cleaning.
Personally I didn't try it yet.

Ellacino

Hi easyedwin, dand and 350MH83
Have any of you guys had the smell ?

Ellacino

Sorry 350MH83, just realised you already said you did

DanD.

No I don't.

pcy

To prevent mildew and related smell from AC vents, what I do is turn off the AC and turn on just the fan for 10 minutes before I reach home/destination (to dry out the heater core). This works for me.

DasSchnitzel

I agree. Your evaporator has some mildew on it. What state are you in and where is the car from? Can spray it down with an AC coil cleaner and run tons of hot air through it yourself next time. I've had this happen on every car we've ever owned in FL.

boydenmb

Do you have a diesel or a gas model? I have heard that an ammonia smell is common in the diesel engine model and mine is worse with the a/c on.

350MH83

I had the diesel one. And it is true that if you stop the AC before arriving at your destination there will be no smell on next start.

yavor

I had this problem on my previous bmw. It happened mostly when the temperature outside was close to the chosen temperature inside, as if the system should intake outer air almost without chilling it. I just moved the temp down to start blowing colder air and the smell stopped .
No such problems with the gle for the moment.

jimmysanjuan

I finally got this resolved. Mixed a spray bottle with one quart Isopropol Alcohol, 2 drops of Dawn, and a liberal spray of Pure Citrus lemon oil freshener. removed the cabin filters, ran the car and heater on high with windows open while spraying the mixture thru the fan (slowly so that it wasn't pooling and not getting to the evaporator area) Took a few minutes of patient spraying to get it all thru the system. Let the car continue running with heat on high for 10 more minutes to thoroughly dry everything up. Replaced the filters with new Mahle filters. It's been a week, and all seems OK. No more stink on startup. I've used the commercial/professional products before, and this worked better.

ML350Montreal

i had the same problem and changed the cabin filters