Topic: Foul smell from BMW AC

[KD]

I don't recall this ever happening to any of the cars i have owned and my wife is very sensitive to strange smells, but I've been in a few cars in the past with a stench coming out of the ac vents.  As already mentioned mold growth from a blocked drain line seems like the most likely cause.  I have never bothered turning off my ac system for a while prior to shutting off my car, but it may help in this situation...  

[ArticSteve]

I'd be a tad concerned with Legionnaires Disease.

Legionnaires' disease (LD) is a major cause of severe community-acquired pneumonia but the source and mode of transmission are not always apparent, especially in sporadic cases. We hypothesized that LD can be acquired from the air-conditioning systems of motor cars. Swabs were taken from the evaporator compartments of the air-conditioning system of scrapped cars. Healthy subjects who were mainly employees of regional transportation companies were tested for antibody to Legionella pneumophila serogroups 1-6; they also completed a questionnaire. Legionella species were detected in 11/22 scrapped cars by the loop-mediated isothermal amplification method. The prevalence of microplate agglutination titres > or =1:32 was significantly higher in subjects who sometimes used car air-conditioning systems. Although we did not prove a direct link between Legionella spp. in the car evaporator and LD, our findings point to a potential risk of car air-conditioning systems in LD, which needs further investigation.

http://www.ncbi.nlm.nih.gov/pubmed/19379540

[tooscoops]

my buddy just had this happening in his volvo and i responded with the same... i had thought volvo's had some kind of afterblower thing to prevent it... ah well...

then he went to show me and it blew out a mist at start up... the volvo techs told him there was nothing wrong.... goofs... it is quite common... usual signs are the smell or a wet passenger floor...

[HeliDriver]

^^ I think the smell can be caused by just a bit of residual moisture on the evaporator (which can be taken care of by running the fan), but if the passenger floor is wet, or if you can actually hear water sloshing around, that suggests a clogged drain (which will need to be unclogged).

[tooscoops]

yeah, sorry.. should have specified that.... i find the clogged drain tends to be a precursor to smell in a lot of cars... especially if no one sits in the passenger side to let you know the floor is wet!

my assumption is that if there is a large amount of moisture left, there is probably a clog.. like my buddies case where there is enough moisture to actually blow out! i've dealt with more people coming in for a clog than just residual moisture here at the shop...

[sailor723]

BMW now thinks thee may be a problem with the ventalation system doors. The car is being picked up and taken to Moncton next week for further diagnosis.

[KD]

BMW now thinks thee may be a problem with the ventalation system doors. The car is being picked up and taken to Moncton next week for further diagnosis.

That's a good service move.  I assume they will leave her a loaner...?

[sailor723]

Yep...that's what they say. Last time it was loaded X1.

[sailor723]

Well, the X1 was returned late Friday after 3 days at the dealer. The smell is gone. According to what the service manager told my daughter it involved changing the coolant and taking the dash apart for cleaning and replacing several of the doors in the HVAC system. Appearantly this was done after consultation with BMW and at their direction. This agrees with several accounts of the problem and it's fix that my daughter said she found on various BMW forums. I'm not sure how the coolant was an issue but appearantly it was.

 Anyway, kudos to BMW Moncton and BMW for dealing with the issue.

As an aside.....the loaner this time was a new 328i sedan with about 3K on the clock. My daughter commented on how the steering felt "sloppy" and "loose" (her words) compared to her X1 (E90 based) and that the ride seemed softer. I guess there is a noticable difference.  I actually had my wife's 2011 328i there for service a couple of weeks ago and had a 335i as a loaner. Now that I think about it it seemed a little less taunt in the steering and suspension department as well

[wing]

Steering is electric now and much lighter for sure.  Although IMO BMW steering was ridiculously hard before.

[Julie]

Your daughter sounds like someone who appreciates good steering. I loved the E90 steering, even if it was heavy.

[sailor723]

AAAAAAAAAAAAAAAAAAnd it's back!

The smell was gone for about 2-3 days and then started to come back. It's there full force now after a week whenever the AC is on. My daughter did some digging online and found an account of a BMW owner with the same problem that had multiple trips to their dealer before finally switching to another BMW dealer who said "Oh, that's probably a leaking evaporator." They changed out the part and the problem was cured.

Call going into BMW Moncton tomorrow. We'll see what they say.

[jamie1]

AAAAAAAAAAAAAAAAAAnd it's back!

The smell was gone for about 2-3 days and then started to come back. It's there full force now after a week whenever the AC is on. My daughter did some digging online and found an account of a BMW owner with the same problem that had multiple trips to their dealer before finally switching to another BMW dealer who said "Oh, that's probably a leaking evaporator." They changed out the part and the problem was cured.

Call going into BMW Moncton tomorrow. We'll see what they say.

It the evaporator was leaking enough that you cool smell something, you would have lost all the refrigerant. I still stand by my original  statement. No doubt that replacing the evaporator is curing the problem because you are ridding the system of the mold. 

[sailor723]

Well, regardless of what the issue is, the next step (according to BMW Moncton) will be to replace the evaporator

[Wetson]

My 03 Mini did that.  It has to do with the AC system.  The best way to get rid of it is to turn the heat on high and let it run for a bit after using the AC... that's what the dealer told us.  None of my Honda or Acura's have ever done that.  It's clearly a design issue.