porsche996tt_tpe

Hi all,

Want to get some advices here.

The car is 2002 996 turbo, but the AC system is the same as regular 996, I think. The wind box, recycle-air motor, the dry canister, the expansion valve, the control panel the compressor all have been replaced and coolant filled to spec.

The aircon works great and normal only in the first 30-40 minutes. But then after that the air is only moderately cool and the recycle-air motor would stop working (meaning that you can switch btwn indoor and outdoor air inlet) and the fan speed becomes slow.

If you leave the car off for a couple of hours, it would just be normal again and 30-40 mins later, the same thing happens again, like the efficiency is way down, but not completely off.

Any suggestions? Thanks!

jumpy chunky

You may have checked this, but make sure your radiator fans are working when AC is energized.
Compressor may be shutting down due to high head pressure.

DBJoe996

Is your ambient air temp sensor in the correct position in the front bumper? If it falls behind/inside the bumper it makes the AC system confused.

porsche996tt_tpe

checked, the temp sensor is correct.

porsche996tt_tpe

The fan is working properly.

fpb111

Both fans, on high and low?

porsche996tt_tpe

Do you mean the aux fans? If so, yes, both were replaced 10K and 20K miles ago. They're working.

Over the weekend, took the car to the garage again. Here's what he thought happened, the wind box was icing up (the fins were literally clogged with ice/frost), and so that explains the apparently reduced fan output. This could also explain why the air remains cool even long afterI switched off the "cold" button.

The reason we think is that he installed a copper-made wind box, not the original aluminum wind box. This was done so that no future leaks would happen. He believes the copper version is more leak-resistent. He's admitted doing this to 964 and other older models and they work fine, but not on the 996 model. So there may be a compatibility issue, I guess, between the compressor and the wind box.

So he retrieved the coolant, instead of using the automatic coolant filler, he refilled it from a more conventional coolant tank... I don't know why this is done and now he couldn't check the amount of coolant that was put into it... And it's not icing up probably because of lower coolant level.

Well... He believes that solves it without having to re-install the wind box (which I think is a messy job he's avoiding...) I'm just going to see if this still happens after extended drive.

Any comments?

Thanks. And if there's more I'll report back!

DBJoe996

Huh? Explain what is a "wind box". What is a copper-made wind box? Is coolant actually freon refrigerant? What is a automatic coolant filler? Refilled from a conventional coolant tank? This is so confusing I'm just shaking my head back and forth. I don't understand what you are talking about.