I bought my 1999 Certified Pre-Owned Porsche 996 Coupe a year ago and have had to add freon twice - once after six months and again last week. The dealer had the car three days the first time and could not find the leak but added freon to the system.

This time I took it to a reputable independent A/C specialist for a second opinion and got the same diagnosis - leak too small to detect. The system was checked with dye and U.V. light both times.

Has anyone here experienced this problem and what can I expect to happen next? The two-year Certified Porsche warranty expires in one year and I don't think topping off the freon every six months is addressing the problem. Your thoughts?

 

Sometimes the leak is in the evaporator box (the radiator that the interior fan blows on). If so, you will see the dye in the water that comes out of the drip hose near the front right wheel.

I have also had leaks in the valve stems where you add freon.

These are a couple of places they may not be looking carefully enough...

How much are you having to add each time?

 

Bards Radiator Stop Leak works well.

If the leak is too small to detect, your only option is to keep re-filling the system. Most of the auto parts houses sell a DIY coolant replenishing kit. When the AC temp falls off, top off the system yourself and save a bunch.