[creativ101]

I VE seen a lot of forums about a bad smell coming from vents when the ac is switched on. However, for me, the smell from the vents is when the ac is switched off and the blower is running.
Any suggestions how to fix this?

[cna90]

Originally Posted by creativ101

I VE seen a lot of forums about a bad smell coming from vents when the ac is switched on. However, for me, the smell from the vents is when the ac is switched off and the blower is running.
Any suggestions how to fix this?

Have you changed the cabin filter?
I'd start there.
Also if you have air freshener in your glove box, After a while they'd lose their fragrance and I bet they don't smell that great over time under the sun. Take them off and check.

[creativ101]

Nothing in the glove box.

The smell only comes when I turn on the blower, any temperature (ac off). With the ac on, there's no smell.

[Dephead2004]

I think you'll get the smell of bad socks from the vents irrespective of whether the ac is on or off.

The bacteria causing the smell build up due to moisture that sits in the condenser and ducts leading from the ac to the vents. There are many nooks and crannys that they can feed on inducted grunge from outside.

You can buy a spray that is a disinfectant .

I used Wurth on my e39 but that involved drilling into the ac casing and applying the spray into the condenser which is where the bacteria accumulate. You can try using the spray from the vent side with a plastic pipe?

Prevention is better than cure and I always turn off the ac leaving the fan on a mile from home to dry the condenser a little and inhibit bacterial growth rather than the car sitting with dampness in the pipework.

[Joe-BMW33]

Is the smell burning your nose or watering your eyes?

[creativ101]

Originally Posted by Joe-BMW33

Is the smell burning your nose or watering your eyes?

No

[creativ101]

Originally Posted by Dephead2004

I You can try using the spray from the vent side with a plastic pipe.

Do you mean from the internal vents or the vent in the engine bay?

[Dephead2004]

Originally Posted by creativ101

Do you mean from the internal vents or the vent in the engine bay?

Internal vents. To stand a chance with the external vents you'd have to remove the pollen filters and stuck the product in writhe the fan on full.

Some products release a disinfectant and you put the air flow on recirculate. I found this left a deposit on the interior surfaces. Would not repeat.

Neither worked for me as the real problem lies deep in the ventilation system.

I do believe BMW offer a disinfectant service. You could get a quote for that

[TommyCardello]

I'm in the same boat…

Tried foam sprays twice. Ozone treatment. Vent spray. New filters.

It's better now, but still can feel the smell.

I found this thread from E90 forum.
Link below.
This weekend trying to do the same.

Just got a garden spray, Lysol concentrate (it really smells bad, will try Lysol Lemon. Maybe it's not as bad.)

After 1 quart of spraying Lysol, I no longer smell mold, but Lysol smell is very strong.
At this point it's hard to tell if it eliminated the odor or masked it.
Time will tell.

But hey, I now have a garden sprayer and a bunch of cheap chemicals. I'll keep trying.

Side note. If you also try this, the tube which comes with those foam cleaners works great with garden spray from Ace Hardware.

Let us know what worked for you.
https://www.e90post.com/forums/showthread.php?t=1075529

[RonronEG]

Originally Posted by Dephead2004

Prevention is better than cure and I always turn off the ac leaving the fan on a mile from home to dry the condenser a little and inhibit bacterial growth rather than the car sitting with dampness in the pipework.

I have similar habits although I start a little further from my destination. It's been working well for many years.

[TommyCardello]

Originally Posted by Dephead2004

Prevention is better than cure.

Don't know how about OP but even though it may be a good advice for prevention, it's just so happened that I purchased this car used. This already happened and now I need to find a working solution to eliminate it.


Honestly, all cars I've driven (and this is my first BMW), I've never heard about having to turn off ac 5 minutes before destination.
If it's the case, it's just seems as a bad design.
Just an opinion.

[TommyCardello]

Originally Posted by creativ101

I VE seen a lot of forums about a bad smell coming from vents when the ac is switched on. However, for me, the smell from the vents is when the ac is switched off and the blower is running.
Any suggestions how to fix this?

Just wanted to report back.

No foam sprayers, new filters, ozone generators, nothing worked.
I was going to go to professional mechanics, but they told me they are going to use foam cleaners.
They wanted to charge $170 for a single treatment, while I paid only $20 for a can. It didn't work, so I'm glad I didn't waste $170.


Well, Lysol and garden sprayer like in that e90 forum I shared above, worked.


It's a strong stuff, use some gloves and prevent it from dripping inside the passenger footwell. (I put a deep frying pan there)
But now, after about 2 weeks, Lysol smell almost went away.
And I can't really feel that mold/cat urine smell anymore.

I'm still keeping an eye, or should I say, keeping a nose on it.
But at minimum it significantly improved the problem.

[Dephead2004]

Originally Posted by TommyCardello

Just wanted to report back.

No foam sprayers, new filters, ozone generators, nothing worked.
I was going to go to professional mechanics, but they told me they are going to use foam cleaners.
They wanted to charge $170 for a single treatment, while I paid only $20 for a can. It didn't work, so I'm glad I didn't waste $170.


Well, Lysol and garden sprayer like in that e90 forum I shared above, worked.


It's a strong stuff, use some gloves and prevent it from dripping inside the passenger footwell. (I put a deep frying pan there)
But now, after about 2 weeks, Lysol smell almost went away.
And I can't really feel that mold/cat urine smell anymore.

I'm still keeping an eye, or should I say, keeping a nose on it.
But at minimum it significantly improved the problem.

So now use the prevention trick by turning off the ac while you drive the last mile home to dry out the condenser and prevent the mould growth . Saves fuel too !

Interested to read of the no recirculation tip. How does that work with the auto recirculation our cars have?

[TommyCardello]

Update.
Lysol worked, but a few months later, the smell slowly returned.
I could smell a combo of sweet and sour.

Went to a dealership. I paid them $600 to clean the evaporator. It only helped for a few weeks.

For the sweet smell, they checked for coolant leakage. And found one!
Luckily, I'm still under warranty. They fixed the coolant leakage. It seems like the sweet smell is gone.

But sour is still there. I have no idea what to try next. Does anyone have any ideas?
Is it possible that the smell comes from ducts and not from the evaporator directly?
Could the smell also come from the malfunctioning evaporator or heater core?

Thanks.

[Qsilver7]

Originally Posted by TommyCardello

Update.
Lysol worked, but a few months later, the smell slowly returned.
I could smell a combo of sweet and sour.

Went to a dealership. I paid them $600 to clean the evaporator. It only helped for a few weeks.

For the sweet smell, they checked for coolant leakage. And found one!
Luckily, I'm still under warranty. They fixed the coolant leakage. It seems like the sweet smell is gone.

But sour is still there. I have no idea what to try next. Does anyone have any ideas?
Is it possible that the smell comes from ducts and not from the evaporator directly?
Could the smell also come from the malfunctioning evaporator or heater core?

Thanks.

As mentioned in previous posts…the AC funk is usually due to the growth of bacteria & mold.

Do you frequently run the AC and then park in a dark enclosed location with very little air circulation (like a home’s garage)? If yes, there is another thing you can do to help reduce the environment that is prime for the growth of bacteria & mold.

BMW has a ventilation feature built into the IHKA system that allows the blower to continue to run for up to 15-20 minutes after shutting down the engine. This works great to help evaporate any condensate/moisture…which can help reduce the environment for the growth of bacteria & mold…basically shining a light on their dark “love nest”.

I actually programmed one of the 1-8 preset buttons so that i have quick access to the ACTIVATE NOW button…so that if im running the AC and find myself parking in a dark/low fresh air location…i just activate this feature after pressing the START button to turn the engine off.

The engine must be turned off to activate the activate now feature. I’ve been using this feature for decades after discovering it can help prevent AC funk. My 97 e38 & 99 e39 had this IHKA feature & i used it frequently during the summer months…i cant remember if mt 91 e32 & 95 e34 he this feature…but do remember the blower could be activated with the engine off (the REST feature).

The pics below shows this ventilation feature in my 2014 X5’s version of iDrive. Your newer version LOOKS different but this ventilation feature is still in your newer version of iDrive.

[540iSUP]

It’s bacteria that you’re smelling. Turn on your blowers and get some Lysol disinfectant spray. While your blower is on full blast, spray the crap out of all the vents on the exterior, under the windshield wipers.

Try to keep that area clean when running your AC. After running your AC, turn it off and keep the fans on full blast and open them up to exterior air for a few minutes. This will dry out any trapped moisture and prevent that smell from coming back.

[540iSUP]

Sometimes I would change out the cabin filter and spray Lysol in the area the filter sits, and I’ll spray the filter and run it through the blower.

[Qsilver7]

Originally Posted by 540iSUP

… After running your AC, turn it off and keep the fans on full blast and open them up to exterior air for a few minutes. This will dry out any trapped moisture and prevent that smell from coming back.

This is what I was trying to convey in post #15…except I don’t have iDrive 7…but I assumed that the procedure could easily be extrapolated since the feature is found the same way (pics/wording may be slightly different) but the path to find it is basically the same: SETTINGS —> CLIMATE —> VENTILATION. And again, you can program one of the 1-8 Preset buttons so you won’t have to drill down through the iDrive screens.

You can also activate it through the the BMW app…just look for the fan icon…and tap on it to you get to the activation button. Once activated, a little fan icon will appear to verify that its in use.

This feature will run the blower to help evaporate moisture in the vents and on the condenser…lessening the ability for bacteria and mold to form…then automatically shut down. You can activate it anytime you need it when you’re shutting down the car. Or even if you walk away and forget, you can open the app on your phone to activate this feature.

The instructions are also in the physical owners manual, the manual embedded in iDrive, and the version in the app.