My new to me 2000 C2 seems to only hold a freon charge for about 2 weeks. The system is cooling very well when charged, so just a leak somewhere. Is there a common leak/failure point I should look for? Thanks!

 

The Porsche's have a lot more hose than most cars, so I would suggest there is a small hole/crack somewhere along the lines. The way to find the leak is to have it uv dye tested. The other area could be the compressor seals which, like all seals can dry out and leak.
If you're doing it yourself make sure you don't over charge. If you need to replace the hoses use Barrier Hose.




Hope this helps.

 

You should also replace the dryer given your system has been exposed to atmosphere. As other reply noted, need UV test.

 

Time to get out the dye and CSI glasses - thanks! BTW, what is "Barrier Hose"?

 

Barrrier hose has an additional layer of material (nylon like compounds are best) to reduce the permeation of the refrigerant and is recommended for the newer R-134a refrigerant. If one's A/C hoses have been in use and are not leaking and one converts to R-134a due to a compressor failure or upgrade it is not necessary to replace the hoses. Apparently the mineral oil used in the R-12 systems has internally coated the hoses and stays in place since it is not miscible with R-134a refrigerant. This oil coating keeps the permeation of the R-134a within reasonable bounds. However, if a hose goes bad one should replace it with one made with the new barrier hose even if one is staying with R-12.

You can get it through Pelican Parts.

 

I would say it's time to visit the shop/A/C person to have it fixed correctly - and quickly. Unless, of course, you have a lot of time and cool weather to mess with it. Since the weather for the next week in Valrico is in the 90's - I would do it tomorrow.

 

I have the same issue. However, my recharge gets me 12-16 weeks easily. Our "official" Porsche dealer mechanics suggested changing whole of tubings (with a price tag of ~ 3000$ for the parts only)!!
Recharging freon is around 80-90 $.
So thinking of sticking to recharging for now... Unless this can cause bigger damage on long term. Could it???

 

I had a similiar experience before on another car and shops were also suggesting the same thing. In my case, I got lucky and it ended up being a $2 Schrader valve that was slowly leaking.