Smelly Heating in F11
Discussion
Hi, I've had my F11 for neatly 4 years and every now and then there is an awful smell in the car when I get into it, it's like a damp, farty, eggy smell.
It starts off faint and then gets worse over a period of weeks.
The first time it happened I tried one of those fragrance bombs and that didn't help, then BMW did a air con clean/ service and that fixed it, until the following winter, it seems to happen when the weather is damp and wet.
It gets gradually worse with time, but when it's not strong it goes after a while, maybe 5 or so miles of driving only to return the next time you get into the car. I have found that running the heater on max for a 30+ minute drive, setting the front vents to hot, and having the fan speed up to 3/4 seems to get rid of the smell. At least for a few weeks, but then it starts to come back if the weather's not good. There are no damp carpets or trim I can find and because running the heater hot clears the smell I assume moisture is somehow getting into the heating system and going off? Are there any drains which could be blocked I can check, or possibly covers of some sort missing?
Cheers
It starts off faint and then gets worse over a period of weeks.
The first time it happened I tried one of those fragrance bombs and that didn't help, then BMW did a air con clean/ service and that fixed it, until the following winter, it seems to happen when the weather is damp and wet.
It gets gradually worse with time, but when it's not strong it goes after a while, maybe 5 or so miles of driving only to return the next time you get into the car. I have found that running the heater on max for a 30+ minute drive, setting the front vents to hot, and having the fan speed up to 3/4 seems to get rid of the smell. At least for a few weeks, but then it starts to come back if the weather's not good. There are no damp carpets or trim I can find and because running the heater hot clears the smell I assume moisture is somehow getting into the heating system and going off? Are there any drains which could be blocked I can check, or possibly covers of some sort missing?
Cheers
gizlaroc said:
This happens when people turn off the climate, bacteria starts to grow inside and it smells.
There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
A/C climate is and has been on 24/7 for the last 4 years.There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
bmwmike said:
Check your condenser is actually working. Also check your carpets are not wet.
Occasionally worth running the climate on max heat for a while to try and dry out bacteria.
Yeah the max heat thing is what I've been doing every now and again when it gets bad, but it's not particulaly nice driving at 28degrees even in this weather with the windows open Occasionally worth running the climate on max heat for a while to try and dry out bacteria.

EDIT: carpets are all dry in all footwells and the boot.
Edited by Mr_Yogi on Friday 21st December 13:46
gizlaroc said:
Do you ever get any misting on the windows?
Nope, A/C works perfectly, nice and ccol in the summer, clears the morning mist in the damp/ winter days.EDIT: Like I said BMW did the anti bacterial clean a few years back and that sorted it, but I don't really want to have to spend £100 or whatever they charge these days each winter.
Edited by Mr_Yogi on Friday 21st December 13:45
gizlaroc said:
This happens when people turn off the climate, bacteria starts to grow inside and it smells.
There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
Common wisdom seems to be to run AC all year round, but the problems with that, for me at least, are:There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air movement prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
Edited by chrisgeary on Friday 21st December 14:06
chrisgeary said:
Common wisdom seems to be to run AC all year round, but the problems with that, for me at least, are:
a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air circulation prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
Cheers, that seems plausable. I've always been of the opinion to keep the A/C on 24/7 as Gizlaroc suggested, but that obviously isn't working for me now, although I have never had problems with previous cars. So I'll give it a go for a few weeks and see how it goes.a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air circulation prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
chrisgeary said:
Common wisdom seems to be to run AC all year round, but the problems with that, for me at least, are:
a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air circulation prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
I do agree with you. a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air circulation prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
But, as you say, you need to run it for the first 5 minutes or so, and that is where many get it wrong.
Mr_Yogi said:
Nope, A/C works perfectly, nice and ccol in the summer, clears the morning mist in the damp/ winter days.
EDIT: Like I said BMW did the anti bacterial clean a few years back and that sorted it, but I don't really want to have to spend £100 or whatever they charge these days each winter.
If you have no excess moisture in the cabin and full heat gets rid of it for a bit, I would get one of the anti bacteria bombs and just do that. £20 is better than paying BMW £100. EDIT: Like I said BMW did the anti bacterial clean a few years back and that sorted it, but I don't really want to have to spend £100 or whatever they charge these days each winter.
chrisgeary said:
gizlaroc said:
This happens when people turn off the climate, bacteria starts to grow inside and it smells.
There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
Common wisdom seems to be to run AC all year round, but the problems with that, for me at least, are:There is not reason at all to turn off climate, it will dry out the seals and cause leaks.
Remember, the climate is also a dehumidifier.
a) that the evaporator is always moist.
b) come winter time below 3-4c the compressor will stop running anyway.
That constant moisture is why it eventually starts to smell as it becomes a breeding ground for bacteria. Provided it has been dried out, not using AC will NOT cause it to create bacteria and the musty smells associated with it. It's the same with home AC as well. Annual maintenance of home AC indoor units at the end of the warmer months is needed to keep things healthy because it isn't practical to dry out the indoor unit every day. Whereas in a car, you can use the AC, then turn it off a mile or two from home and dry it out. I don't typically do that in summer because it isn't practical, but in the milder months either side, its perfectly practical.
After a few decades on the road and not using AC full time (but still using it every few weeks to maintain the seals), I've never had AC fail due to perished seals, never had to "bomb" clean it and my windows never mist up during wet weather. Use a moderate fan speed and air movement prevents misting.
Using AC full time is precisely the reason why they start to smell because the evaporator is permanently wet. Choose to run AC as little as possible will help to keep the evaporator dry and bacteria then cannot form.
Edited by chrisgeary on Friday 21st December 14:06
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