My 2015 Tfsi was blowing perfectly cold, cooling the entire car, ALWAYS set at 69 degrees, year round, but since my engine rebuild and the disconnection of the A/C lines and having to have it all recharged properly, this thing just doesn't get really cool like it did before.
It does blow cold, but never gets really cool in cabin, unless and IF I set the controls to LO! Then it blows super cold, but still doesn't ever really get cold in cabin. Now I am not sweating, it gets somewhat comfortable, but I keep it at or under 66 at 92 outdoors.
Now, I did just move to the Devils Armpit, South Carolina and its like 98 every day, but I have had it setting in the sun all day and it still got cooled off prior.
After taking it back to the shop to have them check their job, it came back working properly in designated limits, no leaks. So they recommended and I changed the cabin filter, which was on my list, they suggested to use cheaper ones for better air flow, but again, the Bosch hepa filter was working fine prior.
Could there be something in the intake air duct that would restrict flow causing it to not get cold? Seems like I would hear that, but just asking.
Any other ideas I should be checking?
I remember the move from CA, going through Nevada at 110 towing my overloaded trailer and it was completely comfortable.

On another note, my car doesn't use oil any more! I am coming onto the 175,000 service and excited to get it done within the next week or so. Then my Qx80 140,000 following.

Thanks in advance!

 

Did the shop confirm they used R134a in the system (as opposed to the now-standard 1234yf)? IIRC, the system can work with the wrong refrigerant, but it may not be good for it or work as efficiently due to the different chemical properties and operating specifications for each refrigerant.

Side note: 134a is getting to be crazy-expensive!

 

Playing the 'Devil's advocate' here, but since you had the engine out and A/C lines were disconnected there's a pretty fair chance your A/C's drier module is simply saturated from the system sitting around opened up, and they wouldn't have replaced that as it wasn't their focus. Even if they pulled vacuum on the system, leak-checked it, and refilled it properly, if the drier was compromised while the engine was out, that'll keep your performance at sub-par. The drier is mounted on one side of the A/C evaporator (in front of the radiator), and is replaceable/serviceable, but you gotta discharge the system, change it, then pull vacuum and recharge the system again, etc.

When you turn A/C down to 'LOW' it turns on the recirculation/closes the fresh air vent, and boosts the fan to high mode, so yeah, that's why it feels better for sure, but still not cold-cold like it used to get on the normal temp setting.

Pretty sure that drier is your most likely issue right there, but check the serpentine belt condition and the drive pulleys to be sure there's no gunk wedged down in the grooves of drive pulleys, etc., and pull up the plastic trim piece over radiator and look downwards at the A/C evaporator to see if anything has collected right in front of it. That affected my Q7's A/C system, and so I cleaned out the 'blanket' of pollen and gunk I found in there and rinsed it all out, and my A/C performance improved. Similar improvement was gotten by cleaning the drive pulley grooves and replacing the serpentine belt / tensioner, etc., which I was overdue on.

I also buy only the Bosch Hepa cabin filters for my Q7 as extremely effective for keeping my allergies at bay...and shockingly inexpensive for such a high quality cabin filter. Definitely need to change those out every year though to keep the airflow up and less stress on the blower motor. How cold your air coming out of the vents is doesn't depend on the fan speed. Get a digital thermometer to see how cold the air is at the vents, and if it differs at all side to side in the car, which might indicate a blend door issue, etc. Also, check out the A/C in the rear seat while you at it. If it's cool-cool back in the back, that tells you something is amiss with the front system, so worth checking IMO.

 

Good question! They did ask what it used prior to the work, while making the appointment and I did tell them that and they said no problem, but now I am curious.

 

Hmmmm...... Possible on the drier
This had new belts and tensioner installed, which I was going to do once returned to me, That all seems right, but I will go back into check it all anyway.
I'll get a thermometer (any recommendation) to check all vents. Blend door? It use to make crazy sounds in the behind dash and now it does not, so perhaps? But, I did play with positioning and it seemed to function properly.

 

The temperature blend doors are separate items/different from the air outlet routing doors/servos, which control where air exits the vents, just FYI. That's why strongly suggest the low-hanging-fruit approach; get in the backseat and check out the rear HVAC system's performance, both at idle and also with someone else either driving or holding revs up a bit to allow the A/C compressor to do it's thing. This comparo is much easier to make legit with the digital thermometer readings at each outlet. VCDS can also show you the internal temp measures from the A/C system(s) monitors, etc., as a point of reference.

If also subpar cooling in the rear is found and no faults/door issues present on it, then that supports the problem is with the A/C drier or freon charge/type used. It's just a matter of whittling down the variables you can directly observe. The thing I didn't mention prior is the higher humidity makes you feel hotter even in an A/C environment, so if the system can't effectively reduce the humidity in the air, then you'll still feel 'hot', and this is where that recirculation function comes into play prominently.

If you go into the A/C menu on the MMI, there is a control for "Auto Recirculation". Make sure that is turned to ON/Auto mode. On both our Q7s I've found that function/feature is turned off, and it likely defualts to OFF when battery is disconnected is my theory, and in the Summer heat/humidity of the deep South, and elsewhere I'm sure, that one, innocuous sounding A/C system setting makes all the difference in the world for your comfort.

 

I will check the MMI when the wife gets home with it.
I drove out about 15 miles and back this morning, set it to LO and it got so freaking cold I wanted a jacket, even after turning back to 66. The wife even commented it was much much colder and she is always on fire any more! I turn her seat fan on!

 

Yup, that's from keeping the outside humidity outside and just dealing with the humidity present in interior of the car...lower humidity makes it feel colder. The downside to leaving recirc turned on all the time is it'll get too dry, which makes it less comfortable and less effective, and you start to get that dank smell inside car from recirculated air...especially if someone's had beans or potato salad for lunch. The auto-recirc function (MMI function) only works in the HVAC's AUTO mode so far as I know, but that's what most owners leave it in during Summer I reckon, and just twirl the temp **** to get things where they like it. That way you get the benefit of fresh air, but the car is fairly aggressive with the recirculation to control the humidity inside car for optimal cooling.

 

I checked the MMI and of course, you were right, it was turned off.
It is 102 on the dial, so sitting still may take all day to function, so I have to go out later and I will check it then, to see if it helps. PRAYING IT DOES!

 

I have never taken it out of Auto setting and only occasionally set a little higher or lower, but 99% off time it sets at 69 degrees.
Now my wife will turn her fan way up or down, depending, tripping out of auto. I reset as soon as she is done. I do that for dual and 4 zone also.