BimmerFest BMW Forum banner

E9x Air Conditioning in Arizona - any good at all? Anyone?

2K views 18 replies 13 participants last post by  DSXMachina 
#1 ·
Hello.

There have been many threads posted here about failures of the air conditioning system on E9x vehicles. Many, including my own, have been in Arizona. I am on my third evaporator coil and have had more O-Rings, expansion valves, and service ports replaced than I can remember. Many. I sometimes imagine that my coolant is a significant proportion of UV dye by now. I am now one year into the 2-year parts/labor warranty on my most recent evap coil replacement and as the brutal Arizona heat beats down I am again thinking that there is something wrong.

My independent service shop spontaneously told me last month that there seemed to be something amiss with my A/C. My dealer - who have serviced/repaired my car from new - are saying that everything is performing to specification. But, even on a long (30 mins+) drive during the day the A/C is unable to keep up with the solar input and my family and I stick to the seats. Yes, we have dark AZ legal ceramic IR-reflective tint on all windows except the windshield. We prefer using my wife's 10 year old Volvo V70 wagon rather than my 5 year old oft-repaired BMW for any trips. The Volvo has a veritable blast-chiller behind the dash. Never ever been serviced and is just magical.

SO: is there *anyone* in southern Arizona with a 2009 BMW 328i that can verify that the design is able to keep up with our 105F+ days?

If there is then it is a fault with my car, which I have reported since the car was less than 6 months old (records kept), and which I will fight to be remedied. If no one else thinks that their car is able to cope then at least I know that my car IS performing to specification and I shall just make a note to check the A/C performance of my next car with a test drive on on a hot day.

On MAX (60F) setting my vents exhaust cool (not chilly) air which becomes slightly cooler as the car moves faster on a freeway. I suspected that as the compressor spun faster the A/C improved, but the dealer has pooh-pooh'd that notion. Similarly they have discounted out of hand my thoughts that there might be a blockage in one or more of the pipes which is limiting delivery of coolant to the expansion valve. They insist everything is perfect even as I stand there with my shirt clinging to my back.

Frank.
 
See less See more
#2 ·
Frank,

Not exactly the same thing, but years ago I went through a similar thing with my 1994 Honda Civic - it seemed like there was more dye in the system than coolant for all the times it had been under repair. Turned out when we finally put our foot down, and the indy did a full tear down, the leaks were in the back of the radiator; not easily discernible.

Our 2001 MB has now had I think 3 evaporator cores installed. Finally, SO is listening to the indy who explained that it is best to turn the A/C unit off and let it equilibrate with warmer air before shutting the engine off. I believe DSX corroborated this information a couple of years back. Honestly, when it's 99°F and 90% humidity, I have trouble remembering to do this as well, but it really does help in not shocking the A/C system and causing fractures in the aluminum.

We are actually experiencing the same thing with our home A/C. Aluminum cannot stand up long haul to the stresses that copper can. My understanding is that car evap cores are aluminum are very prone to the thermal shock.

Hopefully DSX will chime in here with better (more technical) info than I have given. I know our Texas heat isn't quite the same thing as you experience in Phoenix, but it's probably in its own way just as brutal to a system with the amount of humidity we deal with.
 
#13 ·
Frank,

Not exactly the same thing, but years ago I went through a similar thing with my 1994 Honda Civic - it seemed like there was more dye in the system than coolant for all the times it had been under repair. Turned out when we finally put our foot down, and the indy did a full tear down, the leaks were in the back of the radiator; not easily discernible.

Our 2001 MB has now had I think 3 evaporator cores installed. Finally, SO is listening to the indy who explained that it is best to turn the A/C unit off and let it equilibrate with warmer air before shutting the engine off. I believe DSX corroborated this information a couple of years back. Honestly, when it's 99°F and 90% humidity, I have trouble remembering to do this as well, but it really does help in not shocking the A/C system and causing fractures in the aluminum.

We are actually experiencing the same thing with our home A/C. Aluminum cannot stand up long haul to the stresses that copper can. My understanding is that car evap cores are aluminum are very prone to the thermal shock.

Hopefully DSX will chime in here with better (more technical) info than I have given. I know our Texas heat isn't quite the same thing as you experience in Phoenix, but it's probably in its own way just as brutal to a system with the amount of humidity we deal with.
Cracked metal is an engineering deficiency, in this case bowing to government pressure to build a more fuel efficient car. Aluminum has many issues as a heat exchange material, corrosion and exfoliation not the least. Aluminum - Bah!

Humidity changes air conditioner cooling efficiency in a big way! It's all in the heat of vaporization. See, when water condenses, it releases a large ammt of heat. To change phase from liquid water to gas takes roughly 10X the ammt of energy required to raise its temp from 32°F to 212°F. So when your evaporator condenses water outta the air, it's cooling much, much, much more heat in the Land o'Kat then the Valley of the Sun, at the same air temp.

But Phoenix got temp. Yessir, when mercury says: 120°F, Sky Harbor Airport's grounded and laptop screens refuse to play. Also, metal parts engineered to close tolerances may expand beyond their comfort zone and become somewhat limber....prone to flex!

Ya'll can take it from there. Gimme copper, or gimme death!

 
#3 ·
I wish I had a better answer for you... Although I live in SoCal where temperatures are quite a bit cooler, I took my 335i on a road trip out to Phoenix a couple weeks ago. I saw outside temps as high as 113F on that trip; the A/C in my car had no problem keeping things nice and frosty inside. In 7 years of ownership I've never once had the A/C system serviced.
 
#4 ·
Hi Frank,

My E90 330i seems to do well in Phoenix. This is my 2nd summer with it. I don't think its been any better or worse than other vehicles I have had over the years (I change about every 1 1/2 years). It takes mine about 10-15 min to really get comfortable at the peak of the day, but it does sit outside all day.

Do I dare ask what color the int/ext is?
 
#5 ·
I live in Texas. My AC is tolerable, however in general European cars have pretty crappy AC systems. I'm going to have mine looked at in the spring during my last inspection on warranty
 
#6 ·
My A/C is also marginal on a hot Texas day ... seems to take forever to cool down compared to my two Japanese cars.
Once cool it maintains cool temperatures during the 100 degree days we've had thus far.

I recently had the expansion valve replaced [under warranty] which helped somewhat.
The dealer states that everything is operating normally, but it still doesn't cool to my satisfaction.
 
#7 ·
Maybe this will be a dumb comment... if so, I apologize... Is there any chance that the AC "red/blue" blend knob is actually broken and possibly stuck in the somewhat "not blue" direction??
 
#8 ·
My first thought ... my output temperature varies as the blend thumb wheel is rotated; so no problem there.

[Great observation though; as I thought the A/C in my previous 328i wasn't working well until I realized that the blend knob was in the warm position! :eek:uch::eeps:]
 
#10 · (Edited)
Thank you all. My car is platinum bronze with a light tan interior. The dash below the windshield is of course black. I chose the colors with AZ sun in mind. I'll double-check by red/blue blend wheels including the one facing aft between the front seats. I know they are turned fully 'blue', but the idea that one or both may be disconnected hadn't occurred to me. They have never had very much of any effect on vent temperatures, and of course my dash has been in/out twice now for evap coil replacements so it is possible that something is disconnected. Mine turn very loosely between full-range stops. No finger resistance at all except plastic-on-plastic pivot friction. Any change in vent exhaust temperature is much more imaginary than obvious. Certainly they deserve closer attention.

I understand and have mechanical empathy to the concept of thermal shock to components, but I can't imagine myself ever doing something every time I enter and leave the car to mitigate the failings of what would be a poor design. My present evap coil is several iterations removed from the original E9x design, and even from the design which came from the factory. It ought to have had some strength put back in to compensate for the weakening from a cost-reduction iteration. I'd have hoped that BMW would have engineered to withstand repeated shocks from 180F+ (in-car AZ summer ambient) to something close to 40F behind the expansion valve. I am told that my system is just right for coolant so for the time being I think my evap coil is OK. There are (this time) no leaks and they claim to have pumped out and returned the requisite 1.3lbs.

Frank.
 
#11 ·
I'm in San Diego with (usually) cooler temps here, but this summer we've had weeks of 90+ degree weather with occasional temps in the low 100s and my wife hasn't mentioned any problems with the A/C on her 2011 335is Coupe.

In June we did a 12-day 3,200 mile trip for Oktoberfest in Beaver Creek and we drove through Nevada and Utah with temps in the 90's on the way there and back through New Mexico and Arizona with temps over 100 and experienced no problem with the A/C.
 
#12 · (Edited)
Frank, "Liverpudlian at heart"? I recently watched your hometown team lose 1-0 to AC Milan in the 89th minute of a match at Fenway Park. It was 92F that day and about 80% humidity, absolutely sweltering. My AC was more than adequate to the task...and that's my segue cue to discuss your problem.

You live in AZ where it is much hotter than NH but humidity is harder on AC systems than heat! Ever notice all the water under an AC'd car which has been running in one spot for a while? Probably not in AZ, but in most of the rest of the country it's common. (More on this later.) When an ac compressor runs it compresses a gas, the hot gas is condensed to a warm liquid by the condenser. This liquid has potential to absorb heat when it is returned to a gas. The amount of heat it can absorb ('make cold' in not scientific parlance) is measured in BTU's.

Everyone knows house window AC units run about 5000 to 10000 BTU's. Central AC usually runs 1 1/2 to 4 tons. That is 18,000 to 48,000 BTU's of cooling ability. How many BTU's would you guess your car's AC can generate? I think you'll be surprised to learn that it is well into the household central AC range! Then why isn't your car capable of being freezing cold? It is. Try running it on high at night on a 75 degree day and you'll have a meat locker in no time at all. So, what's wrong with yours? Maybe nothing, maybe something. Let's find out.

In the morning, in the shade, put a thermometer in the center vent. Set the AC fan to the second speed. Close the other vents if possibe. Set the temperature to max cool which should cause the system to recirculate some cabin air. If it doesn't, hit the recirculate button. Bring the rpm's up to 1500 and after 30 seconds tell me what the outlet temperature is. We'll talk further after you tell me the reading.

FYI, Arizona at 120 F. is easier to cool than Florida or Louisiana at 95. Why? No humidity. It takes energy, measured as BTU's to condense water vapor to liquid. If, say, 20% of your AC system's BTU's are condensing water that leaves 80% for cooling. Cars in FL and LA are using a lot of their BTU's to make water before they can start to "make cold". Which leads to an interesting thing to know about AC systems. They don't "make cold". What they do is absorb the heat in the cabin and give it off through the cabin radiator -the condenser. They move the heat by absorbing it into the vaporizing refrigerant and transporting it away. When the heat is taken out of the air, you're left with cooler air. We need to remove enough heat so that you are happy with the temperature of the air that's left.

In AZ there is a factor which does make it tougher. Sun load. Two cars, one in AZ ands one in Oregon have to deal with totally different sun load even if the air coming from the vents is the same. The AZ car is baking in an oven and the cold vent air is soon heated by convection from the dash and all the exterior surfaces. Meanwhile the occupants are getting heated by radiation coming in through the windows. So the nice cool air may soon be inadequate to the task. We need two things, low temperature and high volume to keep you from sticking to the seats. Let's find out what we have.
 
#17 ·
Frank,

Not sure if the system is different on mine as I have a 2011 335i. I live in Phoenix and my air was not cooling well at all. I took it to the dealer yesterday and they told me that I had a leak and they replaced the evaporator. When I picked it up yesterday at about 3:30, the outside temp was reading 112 and the a/c was blowing so cold that I turned it down to half speed. Let's hope it stays this way.

Steve
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top