[cas951]

I totally agree with thstone comment. Your mechanic is just not familiar with the Boxster or Porsche and does not have the proper diagnostic equipment needed to troubleshoot your issue. I went through the issues you're going through about 6 months ago. The 1st shop I brought it to was a independent Porsche repair shop. I asked the to see if they can find the leak but no luck. I tried to avoid the dealer. I then took the car to a shop that specializes in smog issues. He owns a Smog Test only shop and a repair shop next door to it. I asked him to do a smoke test and try to pinpoint the issue. He had the car for a while afternoon and could not find the leak. Lucky for me he was honest and admitted he just didn't have the proper tools to diagnose and did not charge me a any labor. He recommended for me to take it to the dealer which I did.

The dealer ended up identifying and changing three components of the Evan system. To me the dealer was being cautious and did all three and I told them that I felt they were guessing. But in their defense they were probably right in saying that the age of the car the other components is likely to fail in a short period after leaving the shop. I went ahead and had them replace all three components.