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Sour Smell from AC - Vehicle is new
- Thread starter John_Waggs
- Start date
Did you ever get any feedback on this?
My M3 is less than 4 months old with fewer than 2500 miles and I am having the same issue.
Hey, I've been suffering from this same problem for the last 2 years, but found a solution and busted a lot of myths along the way. These are my findings over many filter changes/AC foam cleaning and discussions on this forum and others.
1. The solution is to manually toggle off AC and run fan on high for at least 30s (better to do it for a minute, you know it's done when the air coming out of the vents is no longer cool) before leaving the car.
2. Try to leave recirculation mode to AUTO and don't manually recirc. Most forum members including myself who have the smell issues seem to have used manual recirc.
3. The smell is the WORST for short stops. If you leave the car for 5-20 minutes after driving with AC running, then the AC smells absolutely foul when it restarts again. The solution is to either do the manual AC drying procedure, or to use "keep climate". When it's hot outside I just use keep climate, and if I care to save battery charge, I'd change the keep climate temperature up to 74f so the AC doesn't need to blow super hard while I'm away.
Myths busted:
1. It's not the filters that causes the smell, I've taken out filters when my car absolutely stank like wet feet and the filters are usually very clean. Even if they're not clean, they don't smell AT ALL. I even tried wetting the filters, wondering if the smell appears when they're wet or damp, they were not.
2. People keep saying the car automatically dries the AC coils after shut down. If it did that properly, you and I wouldn't have the smell issues. Whatever the car does, it doesn't do it well enough to get rid of the smell, not like when I manually turn off the AC and blow dry the evaporator!
3. Some say that this only happens in moist areas. I'm sure it happens MORE in humid locations, but I'm in LA where it's pretty dry and it happened to my car anyway, and I park indoors all the time in a climate controlled garage.
AC foam cleaning does work (but doesn't work well with small cans, use a big 19oz can if you can), however the smell will come back within 2-3 months (maybe 5-6 months max if you're lucky like some other forum members). The ONLY solution I've found that works every time is to do the AC off blow dry manually. I haven't had to change filter or AC foam clean in the last 7 months now, and I've done 5 AC foam cleanings over the last few years along with filter changes.
1. The solution is to manually toggle off AC and run fan on high for at least 30s (better to do it for a minute, you know it's done when the air coming out of the vents is no longer cool) before leaving the car.
2. Try to leave recirculation mode to AUTO and don't manually recirc. Most forum members including myself who have the smell issues seem to have used manual recirc.
3. The smell is the WORST for short stops. If you leave the car for 5-20 minutes after driving with AC running, then the AC smells absolutely foul when it restarts again. The solution is to either do the manual AC drying procedure, or to use "keep climate". When it's hot outside I just use keep climate, and if I care to save battery charge, I'd change the keep climate temperature up to 74f so the AC doesn't need to blow super hard while I'm away.
Myths busted:
1. It's not the filters that causes the smell, I've taken out filters when my car absolutely stank like wet feet and the filters are usually very clean. Even if they're not clean, they don't smell AT ALL. I even tried wetting the filters, wondering if the smell appears when they're wet or damp, they were not.
2. People keep saying the car automatically dries the AC coils after shut down. If it did that properly, you and I wouldn't have the smell issues. Whatever the car does, it doesn't do it well enough to get rid of the smell, not like when I manually turn off the AC and blow dry the evaporator!
3. Some say that this only happens in moist areas. I'm sure it happens MORE in humid locations, but I'm in LA where it's pretty dry and it happened to my car anyway, and I park indoors all the time in a climate controlled garage.
AC foam cleaning does work (but doesn't work well with small cans, use a big 19oz can if you can), however the smell will come back within 2-3 months (maybe 5-6 months max if you're lucky like some other forum members). The ONLY solution I've found that works every time is to do the AC off blow dry manually. I haven't had to change filter or AC foam clean in the last 7 months now, and I've done 5 AC foam cleanings over the last few years along with filter changes.
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