Hi all,

Want to get some opinions 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!

 

Make sure the pressures when filling are EXACTLY on spec, in my experience the german cars with 134 are very finicky on fill and even a small amount will affect how it works. Your typical AC shop is not capable of this job for the most part, they tend to pump/fill/run without really stretching the system to make sure its working correctly, if one of your fans is not working it also affects the system.

 

First of all, let's rule out the electronic thermostat. Put the AC is manual mode and dial the temps down to "LO". Put the air on full blast. Go drive the car in hot ambient outdoor temps for an hour and see if you lose cold air after the 30 min time period. Report back.