[frstsaxman]

Hi everyone,

I have search all over the internet and I found some people with a similar issue. Some people say that its a known issue and the dealership should know about it. I took my car in for this issue once after it had been happening for a long time but I could never reproduce it for them. I have a 2006 E90 325xi sedan which is now out of warranty so just taking it in is expensive. Hopefully someone has encountered this problem and can help me out. And if so hopefully someone could give me advice on how to get the dealership to cover this because I did bring it in for this issue when it was still under the extended warranty.

My problem is: I drive an hour and 30 minutes every Friday and Sunday. On hot days usually during every summer, when I need it the most, my AC just gives up half way through the drive. After about 40-45 minutes the air stops blowing and its not as cold and sometimes not cold at all. Opening the windows is not helpful because its hotter outside usually. I hit the max AC button and I can hear the blower working really hard, like it should be, but there is only a small trickle of air coming out and its not that cold sometimes its even room temperature. The only way it seems to get fixed (temporarily) is by turning off the car for more than an hour. If I stop somewhere and turn off the car for a short while then start going again in 5 minutes the problem starts again. Anyone have suggestions on what this issue is and or how to fix it? or how to tell the dealership they need to fix it?

any advice would be helpful and appreciated. Thanks!

Anyway I would appreciate some help on this issue. thanks!

[Surly73]

I'm presuming from what I read in your description that this is a refrigerant issue and not an interior fan issue or an operator error (if you have all of the blend wheels set at full cold and especially if you blow one of the vents past the temperature sensor in the control unit you can make it start blasting heat instead of cold. MAX AC should override this though and you've said that you've tried that).

You'd think there should be IHKA codes about what's going on. It could be overpressure, or insufficient condenser (that's at the front by the rad) cooling, overcharge or any number of things. The IHKA controls it all now as opposed to separate sensor control loops like in days gone by so the IHKA should know exactly why it's cutting off the AC.

Has the system EVER been worked on by anyone who may have added refrigerant? Overpressure and/or over-temperature cutoff (or sensors misreporting these conditions) sounds the most likely to me.

Is your condenser coil area clean and free of debris? No extra pieces added to the car that might impeded originally designed airflow into this area? Is your main cooling fan (i.e. the one under the hood) functioning properly? What is the main fan doing when the AC cuts out? Roaring away at full speed or doing nothing at all? Does whether you are moving at highway speed or not influence the behavour in any way? What happens if you turn the interior fan down low went he problem starts? - does cold air return? Do you get the feeling that the air is being heated, or just that it isn't being cooled? Is the humidity in the air high when it's not cold?

Here's a document on the E90 IHKA. As you can see it's completely integrated into the middle of everything.

http://www.bawarec.ru/manuals/3er/e9...3er-e90-17.pdf

[BimmerOne]

I have the same car (06 325xi) and encountered the same issue when I bought the car (used). This is supposedly a somewhat common issue and the dealer was able to fix it quite easily. I was told by my SA that this is due to a simple lack of insulation on a sensor which causes the A/C to freeze up. They will have to open the A/C system and wrap this sensor. I was fortunate to have this completed under warranty and no longer have the issue.

[Surly73]

Originally Posted by BimmerOne

I have the same car (06 325xi) and encountered the same issue when I bought the car (used). This is supposedly a somewhat common issue and the dealer was able to fix it quite easily. I was told by my SA that this is due to a simple lack of insulation on a sensor which causes the A/C to freeze up. They will have to open the A/C system and wrap this sensor. I was fortunate to have this completed under warranty and no longer have the issue.

I would love, love, love to see the TSB on this one. Sounds like a bit of an odd explanation because it seems like it's the evaporator sensor lets the temp get too low and causes freezing. Insulating it would just make the problem worse instead of better, but....

For all I know I'm affected by this too, I haven't driven all that long with the AC on since I bought the car.

[frstsaxman]

Surly73: This usually happens on the freeway and the main issue is that the fan stops blowing. It eventually gets less cold also, but the air flow gets significantly reduced. I hit max AC and I can hear the AC system get loud and go on high but there is barely any airflow. I have had the coolant/refrigerant level check when I first brought it in but they said it was good. I generally keep my engine area free of debris, that was one of the first things that came to mind because it almost feels like something is blocking the vents.

BimmerOne: I'm going to call my dealership about opening the A/C system and wrapping the sensor. I have to go in for new breaks eventually anyway.

[AE_BMW_E90]

Same problem with my BMW E90. When i drive on highway after 30-50min AC and blower stop working. frstsaxman, did you fix your problem?

[6ixSpd]

I have the exact same issue as well and still don't have a solution. Hoping someone does.

[Mashman]

Originally Posted by AE_BMW_E90

Same problem with my BMW E90. When i drive on highway after 30-50min AC and blower stop working. frstsaxman, did you fix your problem?

Originally Posted by 6ixSpd

I have the exact same issue as well and still don't have a solution. Hoping someone does.

There is a recall on the connector for the blower resistor connector, it's possible that is where your problem lies.

Check out this post. https://www.m3post.com/forums/showthread.php?t=1004338

[6ixSpd]

Originally Posted by Mashman

There is a recall on the connector for the blower resistor connector, it's possible that is where your problem lies.

Check out this post. https://www.m3post.com/forums/showthread.php?t=1004338

Yup I was about to order a new blower motor fan but figured I'd check my local dealer to see if they're even doing these recalls yet. Sure enough, they are! Booked in for next week, if the connector burned and damaged the blower motor, I think they replace both

[Zaíne92]

Same issue 352i 2006 E92, I changed evaporator due leak, expansion valve, compressor, radiator fan, new radiator, and used compressor. My issue same as what OP described.

[Jesda]

Funny how your AC not working is caused by something that could catch fire.

[mecheng77]

I know on my Volvo, the common cause for this issue is the compressor clutch gap is too large.
The common fix is to make shims and secure them to the front of the clutch. The harder way to do it is to remove the clutch and shim it

[BMVOO]

I have almost the same exact issue. The air gets warmer and the air flow is reduced considerably. Even if you use the max air function there is no real change in air temp or flow. Once the car is turned off and back on it goes back to normal. I have replaced the final stage resistor and wiring that was burned and this issue still comes and goes. It may be related to the HVAC controller. I had a similar issue with an Acura where the relay for the condenser fan was going bad and replacing that fix the issue. I may try that next. But very interested to hear back from other members who have had this issue on how they fixed it.

[nsjames]

if the air is reduced I'd inspect the evaporator for icing.
low refrigerant can cause that.

[BMVOO]

Thanks for the tip. I will get the refrigerant pressure checked. I don’t think that is it however as it will work for weeks on end in 90-100 deg heat in the south east without any issues. This past weekend I had the HVAC off for two days as I was in the mountains. On the way back I turned it on only to get marginal performance. After turning off the car and back on within 5 or so minutes things had gone back to normal.

[ewicky]

Originally Posted by nsjames

if the air is reduced I'd inspect the evaporator for icing.
low refrigerant can cause that.

Ya sounds like icing to me. Park the car for an hour, the ice melts, problem solved. It's possible that your evap temp sensor (which is supposed to turn off the AC at like 2 degC to prevent icing) is probably bad, unplugged, improperly "insulated," or has fallen out of the evap. Use INPA to view the evap sensor, should stay cold but above freezing when the AC is on. Should read about ambient temp when AC is off.

[Whatsabeemer]

I replaced the entire ac system unit (evap, blower motors, o rings) and had a similar issue. On start up the ac blew cool air but within 15 mins it was HOT.

Turns out it was the sensor. Here’s the fix:

https://www.hella.com/techworld/us/b...ormance-38631/

[nsjames]

Originally Posted by Whatsabeemer

I replaced the entire ac system unit (evap, blower motors, o rings) and had a similar issue. On start up the ac blew cool air but within 15 mins it was HOT.

Turns out it was the sensor. Here’s the fix:

https://www.hella.com/techworld/us/b...ormance-38631/

excellent link.