[mashkovtsev]

Hi folks. First of all, I have to say that I had the same issue with my 2014 228xi, and now it's happening with my 2017 M240i.

When the summer comes, and midday temperatures start going over 26C (79F) - my A/C starts freaking out. Even if I started the car in the cold garage, after 20-40 minutes of driving, A/C starts blowing hot air inside.

My air vent regulators are set to cold air. I tried using the max A/C mode, but it didn't help. I don't have any error codes coming up (I tried to read the errors with bimmerlink, and I always ask to check the car for errors at my car shop).

I'm from Ukraine, and I have no access to my car service (I'm far from home). And I'm not sure about the local dealer service competence/price. So I want to try diagnosing the problem myself (sometimes we're traveling for 8 hours straight, so I really want to stay alive at 30C).

I have the OBD2 cable, windows laptop and phone with bimmerlink/bimmercode installed. Any help diagnosing the issue is highly appreciated.

[shadowfax]

My cooling fan stopped working and wasn't throwing any codes. If I was in a lot of stop and go traffic, as opposed to open highway cooling the radiator, the car would start to overheat and the computer would automatically turn off the a/c compressor (and possibly turn on the heat to draw heat away from the engine bay).

[aerobod]

The condition sounds very much like what happens with a frozen evaporator. The A/C setting, humidity and low refrigerant charge level are all factors, together with the temp sensor position.

The 2014 228xi may have been affected in the same way as the BMWs covered in this TSB: https://static.nhtsa.gov/odi/tsbs/20...47927-9999.pdf

There should have been slight programming and sensor positioning mods for the M240i, but the conditions listed in that TSB may still increase the probability of the evaporator freezing. One way to confirm a frozen evaporator is when the A/C stops blowing cool air, park the car for a while and look for a puddle forming under the car as the evaporator thaws. If no puddle forms, then I would have any equipped air conditioning service centre check the refrigerant level before doing any further troubleshooting.

Hope things all work out to your benefit in Ukraine, BTW.

[mashkovtsev]

Originally Posted by shadowfax

My cooling fan stopped working and wasn't throwing any codes. If I was in a lot of stop and go traffic, as opposed to open highway cooling the radiator, the car would start to overheat and the computer would automatically turn off the a/c compressor (and possibly turn on the heat to draw heat away from the engine bay).

Thanks, shadowfax. I’ll try to check the engine temperatures when driving, and when A/C stops working.

[mashkovtsev]

Originally Posted by aerobod

The condition sounds very much like what happens with a frozen evaporator. The A/C setting, humidity and low refrigerant charge level are all factors, together with the temp sensor position.

The 2014 228xi may have been affected in the same way as the BMWs covered in this TSB: https://static.nhtsa.gov/odi/tsbs/20...47927-9999.pdf

There should have been slight programming and sensor positioning mods for the M240i, but the conditions listed in that TSB may still increase the probability of the evaporator freezing. One way to confirm a frozen evaporator is when the A/C stops blowing cool air, park the car for a while and look for a puddle forming under the car as the evaporator thaws. If no puddle forms, then I would have any equipped air conditioning service centre check the refrigerant level before doing any further troubleshooting.

Hope things all work out to your benefit in Ukraine, BTW.

Thank you, aerobod for a detailed reply. I’ll check for a puddle under the car. I believe my refrigerant level is at normal level (I just filled it up a month ago), but I’ll also check it if nothing will help.

[Sportstick]

Originally Posted by mashkovtsev

Thank you, aerobod for a detailed reply. I’ll check for a puddle under the car. I believe my refrigerant level is at normal level (I just filled it up a month ago), but I’ll also check it if nothing will help.

I don't know your situation, but it concerns me that you filled it up last month. My 8 year old 228i has never had or needed the AC system refilled. Why did yours need filling? The root cause of the problem may have been involved then and still exists now...a leak somewhere?

[mashkovtsev]

Originally Posted by Sportstick

I don't know your situation, but it concerns me that you filled it up last month. My 8 year old 228i has never had or needed the AC system refilled. Why did yours need filling? The root cause of the problem may have been involved then and still exists now...a leak somewhere?

I forgot to say one important fact, haha. Both cars came from Copart. That's why the A/C needed to be refilled. However, I checked the A/C once again after it started working badly on 228, it was full, so the refrigerant level wasn't an issue.

[aerobod]

Originally Posted by mashkovtsev

I forgot to say one important fact, haha. Both cars came from Copart. That's why the A/C needed to be refilled. However, I checked the A/C once again after it started working badly on 228, it was full, so the refrigerant level wasn't an issue.

There is a possibility that an unscrupulous or incompetent previous owner or dealer has recharged the system with the wrong refrigerant (sometimes even using butane or propane), so it may seem to be fully pressurized, but won’t function very well. This should be detectable by an air conditioning specialist with the right test equipment.

Unfortunately if this is a case, a system rebuild at least including a new dryer and possibly the replacement of all non-metallic components such as seals, would be necessary.

[Rocky58]

Agree with above experts. I would just add that if it works well with cold air, then quits, and works fine after sitting for 30 minutes, it is likely a frozen component as a known issue that might be fixable with reprogramming. Another issue that can cause the same symptoms is a clutch compressor that loses traction when it gets hot - don’t know if that can happen here - it did with Volvos.

[MarcoZandrini]

The automatic climate control module (IHKA in BMWspeak) needs to be scanned. There are many reasons why the AC shuts off after 30 minutes.

[TrboMike]

Monitor coolant temp with scanner while driving. Coolant too hot=a/c turns off