The point of this forum is (I would like think) is learning, and mutual M3 admiration, not in-your-face arguing.

I was out today cruisin around, thinking, I am driving a sweet vehicle. Sunshine, good stereo, impeccable handling. Nice day. Went to a car show, saw some mint 60s Mustangs .. talk about sweet rides. Take that body, and put a modern Mazda engine and tranny in it ... that would would be heaven.

Can the expansion valve work, then quit? Yes. That could be it.

To me, to build a bypass, ison some leveladmitting defeat. But, if that's whatit takes, then...

 

I agree that one of the points of these forums is learning and hope that you don't feel that I've been "in your face." That is not my intentionat all.
Healthy debate, and the exchange of ideas is where I'm coming from.
I've been around cars since I was ten yrs old, but still have a lot to learn. Things change all the time and with these modern cars nearly completely controlled by an ECU sitting under a seat or a panel somewhere is still quite a mystery to me.
I can also tell you from being in the business that mechanics (technicians, these days) don't have a lock on automotive knowledge either. Some that I've known, though they'd been to the Certification and training classes, didn't always know how to solve eventhe simple problems. The good ones would listen to the opinions others expressed then make a choice. The bad ones would go bull-headed and strong into the oblivion and usually screw it up (like our President for example)... or take a long time to get to the heart of the problem.
No UBM, I have respect for your opinions and want to hear them, even if I don't always agree with you.
Also, it's not always easy getting one's intentions across on a computer keyboard. I am not sure I've read your meaning clearly, as I am not sure that you've read mine as intended either.

On to happier (off-topic) subjects, and a point of reference: An ex-girlfriend and I went to the 30th anniversary of the Mustang @ Charlotte Motor Speedway back in '94. She was into them and wanted one to restore herself. I don't know if she ever saw that dream or not. We drove all night to get there (12hrs.) and on about 2 hours of sleep when to the track.It was afull weekend of fun. It was a blast.

 

I was not implying anything, V1. My bad. The point of my post - which I can see I did not make very well - was that we had thrown our ideas on the table, gone back and forth a little bit, and that I wanted to acknowledge it could be the expansion valve (as opposed to going down the path of getting all omnipotent and insisting that my theory was obviously the best one - as sometimes happens in these forums).

I know what you meanabout the changing nature of cars .. the ECU and all the sensors. It's great that they prevent big problems, and work to help the vehicle run optimally. Butif thedesign logic is wrong, or if there is a unique collision of conditions not properly anticipated by the engineers ...then we as ownerscould be stuck with an unsolvable (or very hard to address) problem.Itseems some M3's are in this territory with respect the air conditioning. In this forum, and elsewhere on the web, I have read a fair bit of complaining about the AC. You have to wonder, how muchdid or have theyreal worldtested this car in desert conditions? They sell it in Australia, the Middle East, the southern US, some parts of Asia that get incredibly hot- you'd think they would have done some due diligence.

Happily(for me) mine has been great to date, in fact Ihave to turn the temp dial to the 10oclock position to prevent being frozen out.

Millridger - Has there beenany progress with your issue?

 

(thumbs-up) and glad you didn't think I was being an ******* just to be one.
This is also one of my shortest posts ever.

 

Hope you guys have some passion left for me.
I just bought a 2008.5 GT hatch. It's white and the windows are tinted.

My symptom was the same as described in the start of the thread. During a HWY trip, the AC completely craps out.

1. the fan speed slows way down.
2. the air is about 10F lower than ambient, which at the time was 95F with 30% humidity.

switching to manual/autoclimate recirc/outside air makes no difference. For that matter, turning the AC on and off made no difference either.

I've got a vent thermometer now. When ambient is 75, the vent temp is 45F, but that is short term driving.

It's been cool this year and I haven't had a chance to test it again above 90 amb. I'm gathering info so I can be effective when I get to the dealer. Any troubleshooting ideas?

 

ok so imma give my opinion on this problem... im an air conditioning technician...car air conditioning is identical to any refrigeration system....you need to trouble shoot your problem...check things for yourself first...look and see if the fan is working and working well(blowing alot of air) at all times...sit in your driveway and run the a/c for a while see what happens under the hood...look if anything ices up or frosts over...if it frosts up its an indication that u are low on refrigerant ...if you are confident enough u can put your hands on the refrigerant lines..one of them (the discharge) should be warm....on really hot days lines tend to sweat this is normal...if it frosts over and u are handy u can charge it up yourself its really easy

 

thanks for the advice. I'll wait for it to happen again and I'll pull over and see what's up.

I get that everthing could frost over, but would that explain the severely diminished fan output?
Is it clogged up or is the unit in a fault state and it's basically shutting down?

I know the basics of AC but not the details of the car systems. I could probably charge it myself but hell it's go < 1000k miles. I'll prolly visit the dealer and say hi.

 

Another toss-out: If the evaporator is frozen, maybe some heat will defrost it... set the desired temp to as high as you can, and see if running in heater mode will give you good airflow from the fan, or at least thaw out the evaporator?