[TitanLH8]

Whenever I start the car with the A/C on, after it's been sitting outside for a while, there is a foul scent (like wet towel smell) that comes through the first few seconds and then goes away. I thought replacing the cabin air filter and intake filter would fix the issue but it still happens.

Any ideas why or what else I should be checking?

[Bmw doubles]

Originally Posted by TitanLH8

Whenever I start the car with the A/C on, after it's been sitting outside for a while, there is a foul scent (like wet towel smell) that comes through the first few seconds and then goes away. I thought replacing the cabin air filter and intake filter would fix the issue but it still happens.

Any ideas why or what else I should be checking?

This from bimshop on FB

[TitanLH8]

I'll have to take a look into that this weekend. Thanks for the notice!

[ey2001]

Originally Posted by TitanLH8

I'll have to take a look into that this weekend. Thanks for the notice!

Let us know if it works

[Tasmanian]

Spray some Lysol in the hood air grill for the HVAC. also, if you remove the cabin filter, spray it and behind it too.

Thanks
Tasmanian

[juststeve]

This is a common issue among E39 owners. If the smell persists, try a product called: fridgie fresh

[mrashton]

This smell is bacteria build up on the evaporator which is mounted within the air distribution box behind the dashboard. You can see it through the slots left by removing the cabin filters. I had mine cleaned chemically by an aircon specialist who sprayed a chemical concoction directly onto the evaporator using a long spray attachment. For the DIYer you can buy a can of aircon cleaner from your motor factors. You close all windows and put the can in the rear passenger footwell with the engine on and aircon on recirculate you let the released contents circulate throughout the system.

[HarinderG]

I've been trying to find a solution as well!

Let me know if anything works

[Qsilver7]

If you do get rid of the smell...there are some steps you can take to prevent it from reoccurring.

As mentioned above...the smell comes from the "birth" of bacteria & mold. When running the AC...condensation occurs and if you cut the car off and the environment is right (dark and damp)...this is a perfect condition for bacteria and mold to grow.

So if it is possible (not extremely hot)...you can turn off the AC a few miles before your destination but keep the blower running using fresh air only. This may allow any built up condensation/moisture to dry out before you park the vehicle.

If the ambient temp is too high and turning the AC off would become extremely uncomfortable inside the cabin...one can use one of the many under-utilized IHKA features...the park ventilation feature. You can initiate the immediate vent feature which will allow the HVAC blower to run for up to 30 minutes (even with the car NOT running) then turn off. Again, this would help dry up any condensate which would help prevent a breeding ground for mold/bacteria.

I've been lucky enough to have had BMWs that had this feature and by using it anytime I've used the AC heavily and I know that I'm parking the car in the garage or other dark place without a lot of ventilation to dry heavy condensate...I utilize the parked venting feature...and I've avoided having the "smelly AC" issue for decades.

If you have the CIC/NBT...you should be able to find this feature under CLIMATE. To activate the "immediate parked vent feature" (seen in pic below) stop the engine from running but still have the car's electronics on...if the engine is running, the selection will be "grayed-out" like in pic below:

[TitanLH8]

^ thanks for the advice on this. I've been using this functionality the last couple of weeks on my car and have noticed that I don't really get that initial hit of foul scent when I start the car. Still have not had a chance to inspect the blower housing cover yet but so far, this has helped.

[Qsilver7]

[HarinderG]

Originally Posted by Qsilver7

If you do get rid of the smell...there are some steps you can take to prevent it from reoccurring.

As mentioned above...the smell comes from the "birth" of bacteria & mold. When running the AC...condensation occurs and if you cut the car off and the environment is right (dark and damp)...this is a perfect condition for bacteria and mold to grow.

So if it is possible (not extremely hot)...you can turn off the AC a few miles before your destination but keep the blower running using fresh air only. This may allow any built up condensation/moisture to dry out before you park the vehicle.

If the ambient temp is too high and turning the AC off would become extremely uncomfortable inside the cabin...one can use one of the many under-utilized IHKA features...the park ventilation feature. You can initiate the immediate vent feature which will allow the HVAC blower to run for up to 30 minutes (even with the car NOT running) then turn off. Again, this would help dry up any condensate which would help prevent a breeding ground for mold/bacteria.

I've been lucky enough to have had BMWs that had this feature and by using it anytime I've used the AC heavily and I know that I'm parking the car in the garage or other dark place without a lot of ventilation to dry heavy condensate...I utilize the parked venting feature...and I've avoided having the "smelly AC" issue for decades.

If you have the CIC/NBT...you should be able to find this feature under CLIMATE. To activate the "immediate parked vent feature" (seen in pic below) stop the engine from running but still have the car's electronics on...if the engine is running, the selection will be "grayed-out" like in pic below:

I've tried this for a few days now, and it works great.
I wish I can code something in where it would turn on automatically every time I park the car.

[Qsilver7]

...glad this tip is working for you, too.