motoguy128

Normally these cycle the compressor based on suction pressure or temperature I think. Pressure/temp drops and they cycle off before it ices up.

I had a Toyota Tercel that would do this after 2 hours. The ice even started sublimating, so you literally had a white fog coming out of the vents. I've seen a Toyota Camry totally shut down the compressor and the AC button light starts flashing in heavy rain on a cool day.

These cars are really cruel. They just work so well, that you'll put up wit ha lot of ****. Plus in my case, a $20k used car is within our budget, a $46k new Q5 isn't. SO you accept some headaches for the low entry fee to the club.

Rohare

I'm glad to hear that others are having this problem. (well, not glad that you are, but that i'm not the only one). I've always felt the A/C in my Q5 was simply under powered for the size of the vehicle, and nearly any time I'm on a long road trip in summer, it freezes up (i'm sure it's icing over), and what I've taken to doing is turning A/C off and just blowing the fan for a while to allow it to thaw. When it's 'frozen,' even with the fan turned up to 12, the volume of air that comes out the vents is about a normal fan speed of maybe 3, yet when you turn the A/C off and the air is routed differently it blows it's normal amount of air at the higher fan speeds. That's another reason that leads me to believe it's iced over.

It's really frustrating, especially living in an area where we get several 100+ degree days every year and humidity. I don't know if it's a larger Audi problem as this is my 3rd Audi and first with any A/C issue, but it's enough to 1) make me not buy another Q5, and 2) look at other brands again, just in case.

An interesting thing is, the first time I had it in the shop for this, they of course couldn't find anything wrong, but did flush and reset the system, after which the A/C worked better than it had before. My experience with all my Audis had been that when i put the system on AUTO (I always use Auto) and the temp on LO, it would blow at 12. My Q5 had only been blowing at 11, until after this work, at which point it started working as I expected, and would go to 12. Now a year later it's not always going to 12. Also on a hot day, it just doesn't really ever cool the cabin down. Makes me wonder if i don't have a slow Freon leak (which i believe low levels can lead any A/C to freeze up worse). The service tech also talked with me about turning on re-circulation, but that doesn't seem to have much bearing on this problem. They did say that the system will actually close the re-circ door when it feels it needs to, even if the light doesn't come on (not sure if this is true or not).

Lately i've had to keep the temperature turned below 65 for it to even begin to think about cooling down the cabin. Why would it only blow at about level 8 or 9 while on Auto and set to say 67, if it's still clearly probably 85 - 90 degrees inside the car?

I will say this, though, i think it's the only problem I've ever had with my Q5 and I've had it just over 2.5 years and it has about 31,000 miles on it.

sorry for the long post... i'm just "venting" (pun intended). )

Redd

I haven't stuck the digital thermometer in the vents yet, but will this weekend to monitor the actual air temperature blowing out.

I did notice that if I set the system to AUTO, it switches to just the four dash vents. I can manually set it to more vents, but when the system powers back on and comes back in AUTO...that's reset, and the RECIRC is also turned off. So keeping the system in "blow more air through more places" will mean manual intervention every time the car is started, a small PITA since that also requires my reading glasses.(G)

Honda and Toyota used to have real junk for climate control systems, heaters that were only good above freezing, and ac systems that could only say "I think I can I think I can" on scorchers. But they got that pretty much fixed by the mid-80's as consumers were demanding standard functional heating and cooling. (Heck, in 1960, who had air conditioning unless they had a Caddy or Lincoln??)

A good AC tech can find a gas leak (it isn't really Freon anymore) of as little as 1/4 ounce PER YEAR when most systems take about three pounds in midsize cars now. The problem is, most AC techs are incompetent or crooks. And the ones who do know what they are doing, usually are stuck in shops that do NOT have a dedicated bay set up to properly test AC systems.

If you can find a shop that uses dry nitrogen to pressure test systems (it is cheap, clean, and doesn't waste refrigerant gasses) the odds are that shop knows what they are doing. But just try to find one.

MP4.2+6.0

Your sense of Toyotas is mistaken from our direct experience. 2004 Sienna loaded AWD. Bought brand new, late in that year's manufacturing run. The "Lexus" of minivans as some described it. Last family mobile before size down to Q5. A/C started fading 75K ish miles. Oops, that was after the early recall for the heater lines (or was it radiator) because they forgot it got very cold in the U.S. Ditto on the rear hatch struts that faded in cold they only figured out years later.

So, what did it do A/C wise: well to start, it would make an oddball clicking noise in dash that would drive you nuts...and yep, freeze up. By 100K it blew the compressor outright. All service had been dealer to be clear. And, still the clicking post compressor change. Diagnosed as something internal to dash stuff and like another grand. By then the vehicle was gone to next owner. Oh, and another dealer managed literally to blow the tranny at 94,600 miles against a 95K mile new car purchased warranty when they tightened an access plate...right into the fluid passages. We let the dealer and Toyota decide who got to pay for that. Oh, and then there were the front control arms. AWD set up (and probably same as RX), 14 book hours to replace. And suspension literally moved back and forth 3 inches in front as they headed south. Unbelievable junk design. Or, the rear diff support that when worn (like they often did per the boards) let it roll back a foot when parked on an upslope. Terrible set up for a kid mobile and front console openable hatch if "parked." Both those got NHTSA reports.

Yep, the Lexus of minivans. Never again. But, hey you could set the A/C on recirc and the setting held. If the compressor hadn't blown that is; it did slightly affect the cricket in the dash sound too as another plus to the Toyota mystique. ;/ From the family friend who bought essentially the same one in the next mode year, pretty similar experiences there, except they also got broken moving door cables a few times. They moved on to Subies after a run of Toyotas...

Redd

Your experience is with one car? One year, one model? And you'd judge thirty years of a whole product line from that?
I've been in a number of their products over the years, and the AC and heaters worked way better than the heater (no AC) in my '68 Mustang ever did. Toyota, like so many others, has had problems and continues to have problems. still, the overall product was one of the best, until some recent slips. Sienna, big AWD? Fairly new venture for Toyota, compared to passenger cars. And there too, the Land Cruiser pushed LandRover off the global market, and the HiLux has been the vehicle of choice for terrorists and warlords world over.
Not perfect products, to be sure. But certainly competitive on the global market.

uberwgn

Redd, I've experienced the same on long road trips in my A4 on extremely hot days. I suspect, as others have suggested, the evap is icing over.

Q5 Bob

Fingers crossed, but I can't remember the last car I had with an inadequate hvac system. I'm sure that there have been some, but it's been a long time and a lot of vehicles. Modern systems seem to generally work well.

Redd

I just double checked, twice. Restating the engine don't forcibly engage "auto", and won't change the vent positions that are used. But it will turn off the "recirc". So...at least only half the foolling around to try leaving it in a "better" setup.

uber, you know, it is possible that there's nothing wrong with our AC systems. And evil agents from another German car maker are sneaking in and pouring some mysterious "anti-air-conditioning" agent into our cars, to make theirs look better.(VBG)

I actually knew a guy who worked for Ford-Lincoln-Mercury ages ago. His job was literally, to fly around the country. When a dealer couldn't fix an AC system, they called in a supermechanic from the maker's regional "zone office". When the zone office couldn't fix it.. they flew in this guy. (Not at random, but on a scheduled circuit.) Eventually he convinced Ford that certain materials simply could not be used in AC systems, they would breed mold. He's part of the reason they use silver and other impregnations in foams and plastics when they want to make sure nothing will grow in them, or on them. Like mildew in evaporator plenums.

Amazing what can be fixed, when you stick a pro on it.

Scott Evil

Good info here! Thanks

LarkTx

This is exactly what happened to me. Complained, they said it was normal, but they evacuated the gas and refilled and it amazingly worked better. I also decided to tint the pano roof to help.