[itshere]

Hi,

As the title says, when I turn on the AC the first 10 seconds there’s a rotten smell that comes out of the AC and then it’s gone. Is that normal? Happens for a few seconds but I think also when I run fan without AC on. It’s quiet hot the last couple days if that adds to anything.

If there’s a fix needed is that something the 4 year warranty covers?

Driving an x5 2020 for reference.

Thanks,

[nZtiZia]

“rotten” as in rotten eggs or vinegar-like? some liken it to Elmer’s glue. that’s likely mold /mildew on the evaporator due to moisture that remains on it. there is a procedure to clean it oneself, but I don’t have the part for it nor can I find it to purchase myself.

someone was quoted $500 to clean at their dealership. I plan to do this. after cleaning the evaporator, the routine will be to let non-AC air circulate for 10-15m after having run the AC. this will dry out any moisture and mitigate the buildup of mildew/mold.

[Dandle]

Your ac has bacteria in it causing the smell. You can get an AC cleaner that will clean it out, you might need to replace the cabin filters afterwards though. I don't think this would be a warranty item but don't know in Canada.

To stop it happening leave the AC on all the time and don't recirculate the cabin air.

[Alan l.]

Change your cabin filters. I also have a 2020 and didn't change my filters until recently and OMG they were gross. I couldn't believe the crap i was breathing through all this time. I use to have this smell time to time but not after replacing my cabin filters.

[Ukd X6]

Hey there

You should check out my post on smelly AC

they had to take my car in for complete AC refrigerator replacement (gas leak)
Other recalls fell under that

All done under warranty By the way

[nZtiZia]

Originally Posted by Dandle

Your ac has bacteria in it causing the smell. You can get an AC cleaner that will clean it out, you might need to replace the cabin filters afterwards though. I don't think this would be a warranty item but don't know in Canada.

To stop it happening leave the AC on all the time and don't recirculate the cabin air.

as an addendum, this means don’t leave it on AUTO because the vehicle may still recirculate the cabin air due to its sensor algorithm. take it off AUTO and ensure the recirculation is not activated.

[mediopogi]

what I’ve learned… when using A/C during the trip, as you reach you destination, turn the A/C off but leave the fan on to dry the evaporator and to prevent it from mold/mildew build up in the long term.

If that isn’t done, the next time you defog the windshield, it will cause the windshield to fog even more before it defogs. This is an indication of moisture/high humidity inside the evaporator box. Mold/mildew and bacteria likes to grow in dark and damp environments.

[jmilner83]

Had to same happen to my G05 and F48. Replaced internal cabin filters myself and the issue has disappeared.

Very simple DIY job:

[swainbmw]

Originally Posted by nZtiZia

as an addendum, this means don’t leave it on AUTO because the vehicle may still recirculate the cabin air due to its sensor algorithm. take it off AUTO and ensure the recirculation is not activated.

I leave mine on recirculate all the time specially, to illuminate those outdoor smells skunks deer carcasses, and especially pollen and I never have this problem

[Dandle]

Originally Posted by nZtiZia

as an addendum, this means don’t leave it on AUTO because the vehicle may still recirculate the cabin air due to its sensor algorithm. take it off AUTO and ensure the recirculation is not activated.

You can leave it on auto. There's a setting in the HVAC controls to leave recirc on off or auto as a separate option.

[nZtiZia]

Originally Posted by Dandle

You can leave it on auto. There's a setting in the HVAC controls to leave recirc on off or auto as a separate option.

sorry let me clarify. I meant automatic recirculation in the HVAC menu, not the thermostat AUTO setting. to ensure the vehicle is not recirculating cabin air in an effort to dry out the evaporator, you have to disable auto in that setting

[Mixelplux]

Best of luck to you. I've been dealing with this issues in my 2019 X5 for over a year.

Here are the things I tried.
Replacing in cabin filter
Spraying AC cleaner into all vents and air intake in engine compartment.
Spraying Foam cleaner into all vents, air-intake, removing incabin filter to spray in there as well
Purchase 2 BMW Fogger to bomb the entire vehicle interior recirculating the air with max heat for 30 mins
Left the car sit outdoor in the sun for a week

All would temporarily fix the issues but come back with 2 days to a week. The dealer said they can clean the evap core for $750 based on a service bulletin however upon looking up the bulletin its similar to what i did in removing in cabin filter to spray cleaner from there. I'm going to hold off unless I see someone else convince my otherwise

[nish_888]

I have the same issue with my 2020 X5. It’s still under the warranty and the dealer is recommending to change the evaporator coil.
I am hesitating because they have to take the whole dash out to replace it and they think that’s the problem but not sure 100% till they take out the coil.

what do you guys recommend? Should I get it done.

I would appreciate your input.

Thanks

[SlowX6M]

I just started having the same problem with my 2021 X6M - I'm pretty such it was fine during the summer when the AC was being used, but now that the heat is being used there is a strong odor coming from the vents. I just ordered a set of new cabin filters, I hope it helps. The car is always parked in an area with no pollen/leaves, so the filters should be clean.

I've never had such issue with my E70 that I've had for 12 years, I did change the filters several times as maintenance items, but it never had any odors. I hope there is not a design defect in the new models.

[makeitbetter]

Can I asked what filter you guys used to replace the cabin air filter?

According to BMW, there's a few different versions and some seem insanely expensive (>$100).

Thanks

[Dandle]

Originally Posted by makeitbetter

Can I asked what filter you guys used to replace the cabin air filter?

According to BMW, there's a few different versions and some seem insanely expensive (>$100).

Thanks

Replace them with activated charcoal filters which reduce odour from outside. They aren't cheap but if you do them yourself youre not lining the dealerships pocket.

[RPA8888]

Originally Posted by Dandle

Replace them with activated charcoal filters which reduce odour from outside. They aren't cheap but if you do them yourself youre not lining the dealerships pocket.

^^^^
This is your solution.

Activated charcoal cabin filter will address the issue.

[makeitbetter]

Originally Posted by Dandle

Replace them with activated charcoal filters which reduce odour from outside. They aren't cheap but if you do them yourself youre not lining the dealerships pocket.

Thanks, do you have a brand that you recommend that fits the G05? Amazon seems to list some off brands I don't recognize.

Originally Posted by RPA8888

^^^^
This is your solution.

Activated charcoal cabin filter will address the issue.

Thanks for the suggestion, same as above, have you had luck with a non-OEM filter replacement?

Appreciate the help.

[Charles45e]

I had exactly the same issue too. Replacing the cabin filter solves the problem

This is what I ordered from Amazon

Pureflow Cabin Air Filter... https://www.amazon.com/dp/B08CMTKPPV...p_mob_ap_share

DIY takes 15 minutes. The only catch is that BMW designs the filter box in a very awkward location and added two screws. Otherwise it would only take 5 minutes

[cellarrat]

Originally Posted by nZtiZia

as an addendum, this means don’t leave it on AUTO because the vehicle may still recirculate the cabin air due to its sensor algorithm. take it off AUTO and ensure the recirculation is not activated.

This is helpful info. When I am behind a particularly smelly vehicle I put it on recirc, but without apparent effect (at least far less than other cars I have owned). I will take this advice in the future and see how it works!


As for the OP, the easiest and quickest 1st step would be to change out the filters. Might not work, but they probably could use changing anyway

[jo2134]

I had a similar issue a few years ago and turned out a dead mouse was stuck in my ac system. BMW couldn’t find it/get it out, had to go to an indy mechanic

[RPA8888]

Originally Posted by makeitbetter

Thanks, do you have a brand that you recommend that fits the G05? Amazon seems to list some off brands I don't recognize.



Thanks for the suggestion, same as above, have you had luck with a non-OEM filter replacement?

Appreciate the help.

Here's a source for filters from an OEM supplier (Mahle):

https://www.autohausaz.com/pn/156730...hoCB4kQAvD_BwE