[DRiveB]

I have been trying to determine and resolve the problem I have with warm air entering the cabin for several weeks now. would really appreciate it if anyone can help.

I live in a tropical country (Indonesia) it's very warm here (27-34 C degrees all year long) and the AC is always on when we drive.

The problem I'm having with my 2011 3.5 F25 X3 , is that as I speed up from 120km/h (75MPH) and higher, it becomes more apparent that I can feel warm air entering the interior. it is definitely not coming in from the main dash air vent. (as ac and cold air is working perfectly fine) Possibly from the lower/feet vents. The warm air feels more significant and warmer when I increase the cruising speed.

I have taken the car to the authorized bmw workshop, where they had diagnosed ,reset, recalibrate, and spent 2 days checking on the flaps on the overall system but had found nothing except the need to add Freon to the AC. And yet today I'm still heating up inside the car every time I hit the freeway.

would anyone have any insights or hhad recover from a similar problem? my car is imported from the UK so it is very much standard to the EU market. hope I can find some help here.

[Kiemyster]

I know what you are talking about, I find that external air penetrates the system when you have it set on its normal mode. Once you activate air circulation, it solves the problem. Your car may have two modes for air circulation, one has an A on it, and one has an M on it. A means automatic circulation, so the car will sense when the air in the cabin is too polluted and bring in fresh air on that command. M means manual i believe, and it locks the system into just re-using the interior air, so be mindful that the air is not fresh and you should crack the window ever so often to get fresh air in.

Since your AC system has been fully calibrated, this should be the only issue now. Good luck.

[DRiveB]

Originally Posted by Kiemyster

I know what you are talking about, I find that external air penetrates the system when you have it set on its normal mode. Once you activate air circulation, it solves the problem. Your car may have two modes for air circulation, one has an A on it, and one has an M on it. A means automatic circulation, so the car will sense when the air in the cabin is too polluted and bring in fresh air on that command. M means manual i believe, and it locks the system into just re-using the interior air, so be mindful that the air is not fresh and you should crack the window ever so often to get fresh air in.

Since your AC system has been fully calibrated, this should be the only issue now. Good luck.

Thanks for this, I had tried to test both modes, and ended up with the same warm air heating up as I increase speed above (75mph/120km/h)

I had tried to check whether there is a leak on the steering seal entering the interior from the engine bay, as well as any rubber seal leaks on the windshield glass. - nothing

the only thing that was apparent is that the steel wall that separates the cabin and the engine bay was really hot. l decided to try and install heat insulation. This did reduce the heat building up as I speed, but I still can feel warm air from the passenger side. I will try to install more insulation.. any other thoughts that I may have missed?

[pungo]

Originally Posted by Kiemyster

Your car may have two modes for air circulation, one has an A on it, and one has an M on it. A means automatic circulation, so the car will sense when the air in the cabin is too polluted and bring in fresh air on that command. M means manual i believe, and it locks the system into just re-using the interior air, so be mindful that the air is not fresh and you should crack the window ever so often to get fresh air in.

The Auto "A" mode detects "outside" air pollutants and automatically switches the system to stop outside air from entering the system.



If the outside air is super hot, I put the system in "M" or manual mode to not take outside air into the vehicle. This will lower the air temperature coming out of the vents since the A/C is cooling the air inside the vehicle rather than cooling the outside air entering the system.

To the OP, I'd make sure you don't have any leaks from the engine compartment through the firewall. Not sure where to look, but it seems if it only happens at higher speeds, you may have an air leak.

[DRiveB]

Originally Posted by pungo

The Auto "A" mode detects "outside" air pollutants and automatically switches the system to stop outside air from entering the system.



If the outside air is super hot, I put the system in "M" or manual mode to not take outside air into the vehicle. This will lower the air temperature coming out of the vents since the A/C is cooling the air inside the vehicle rather than cooling the outside air entering the system.

To the OP, I'd make sure you don't have any leaks from the engine compartment through the firewall. Not sure where to look, but it seems if it only happens at higher speeds, you may have an air leak.

Originally Posted by pungo

The Auto "A" mode detects "outside" air pollutants and automatically switches the system to stop outside air from entering the system.



If the outside air is super hot, I put the system in "M" or manual mode to not take outside air into the vehicle. This will lower the air temperature coming out of the vents since the A/C is cooling the air inside the vehicle rather than cooling the outside air entering the system.

To the OP, I'd make sure you don't have any leaks from the engine compartment through the firewall. Not sure where to look, but it seems if it only happens at higher speeds, you may have an air leak.

Yes this feels and looks more likely to be an air leak. Secondly, the firewall / metal separator is also very hot when you touch it from the interior side. a friend suggested to wrap the down pipe to lower heat effecting the firewall. do you think it's effective?

[pungo]

Are you putting the A/C in recirculate "M" mode? If so, I would check to make sure the outside air is not entering the HVAC. Use some smoke or steam vapor where the fresh outside air enters the HVAC system in the engine bay see if it comes out of the vents. If it does the system is not closing the door the blocks outside air from entering the system.


You should not need to wrap the down pipe. At speed heat should not be building up in the engine bay since enough airflow should be expelling it.

[DRiveB]

Originally Posted by pungo

Are you putting the A/C in recirculate "M" mode? If so, I would check to make sure the outside air is not entering the HVAC. Use some smoke or steam vapor where the fresh outside air enters the HVAC system in the engine bay see if it comes out of the vents. If it does the system is not closing the door the blocks outside air from entering the system.


You should not need to wrap the down pipe. At speed heat should not be building up in the engine bay since enough airflow should be expelling it.

hi all just wanted to update and thank you all for your thoughts and support

I'm happy to post that the problem have been solved. After taking out the whole dashboard it turned out that there was an air leak from the engine bay, in my case it came from the grommet evaporator pipe through the firewall. unfortunately I didn't have the chance to take pictures of it, but by installing a new seal. All is back to how it should be.

taking down the whole dash was not an easy job, and I had professionals and experienced bmw body shop do it for me. As we had the whole dashboard out, we took the opportunity to re- seal everything, service the AC evaporator unit , and add heat insulators on the firewall.

I'm happy to report after a few days of test drives, all is well

[harvanir]

Originally Posted by DRiveB

hi all just wanted to update and thank you all for your thoughts and support

I'm happy to post that the problem have been solved. After taking out the whole dashboard it turned out that there was an air leak from the engine bay, in my case it came from the grommet evaporator pipe through the firewall. unfortunately I didn't have the chance to take pictures of it, but by installing a new seal. All is back to how it should be.

taking down the whole dash was not an easy job, and I had professionals and experienced bmw body shop do it for me. As we had the whole dashboard out, we took the opportunity to re- seal everything, service the AC evaporator unit , and add heat insulators on the firewall.

I'm happy to report after a few days of test drives, all is well

Hi, can you tell me the workshop name and location (i also from Indonesia)?
My F25 also had the same problem. Appreciate for your help 🙏