Got a 2009 blk/blk CTTS with pano roof and 4 zone a/c. It's takes forever to cool in these hot summer days. My 2016 cayenne loaner today also had the pano roof but cooled extremely fast.

Dealer says no leaks, no codes. Anyone else have one that exhibits the same problem? Recommendation for a fix? Was thinking about getting the 3M crystalline tint installed. Thanks!

 

It's the Pano roof...seriously. All you need to remember is more light=more heat. The possibility your 2009 CTTS may need more R134 charge cannot be ruled-out, either...

 

my black 2008 CTT with pano roof is insanely hot (prob not as bad as you 2 in TN and SoCal), but I 100% attribute it to the pano roof.

I placed a 80% film on the roof (the clearest they had at the shop) and it did help, but not enough to justify it if I were to do it again. I'd either go way darker or not do it at all.

A sunshade helped me the most, and like you, my AC does seem a bit weak, but I haven't checked it's R134 levels yet.

 

It's the 4-zone. I just went through all this with Porsche.

All along I thought the 4-zone added cooling power, but in reality, it's less. I have no idea why, but I got ahold of the graphs for vent temps that are in the Porsche repair manual, and the vent temps on the 4-zone start rising much sooner compared to the 2-zone. This was after Porsche topped up the AC (which helped - midas ****ed it up).

I have started turning off the rear AC, and that helps a lot, at least to get the car cooled initially.

The only thing I can come up with is that the AC compressor is the same for the 2-zone vs 4-zone, and it's probably not powerful enough to deal with all the extra plumbing.

I used to suffer quite a bit after the car baked in the sun all day, but after Porsche topped it up, and I turned off the rear AC, it's much better. The vent temps still aren't as cold as my wife's POS B6 A4 1.8T, but they're within the range that Porsche specs, now.

 

Great! I will try with the rear zone off! Thanks for the tip

 

I've had 3 cayennes with 4 zone, I've never really moved them from the Auto wit recirc Mono setting. 2 with Panos and one without and no difference in cooling down time. Generally with 110F to 120F ambient temperatures the the blower will start to drop from max after about 10 mins.

 

No, it blows.
.
.
.
.
.
Joking aside, my AC is pretty weak. It can't handle Texas heat and takes 20+ minutes to get cold in the summer. When it's really hot, the blower loses its power trying to fight against the Texas heat.

 

I'm just stating what my experience was, and what the Porsche manual says. The workshop manual clearly shows the 2-zone holding cold vent temps up to a much higher ambient temp range than the 4-zone.

My air-cooled 911 couldn't keep the oil temps down in traffic up here at 5500 ft. But, they were rock steady when stuck in LA traffic because the air is thicker and more efficient at removing heat. I suspect, for me anyway, that this plays a roll as well.