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thom4782 · 09-24-2012, 06:29 PM

I have a slow leak in my A/C system. The independent A/C shop thinks its the evaporator. The dealer tells me it has never seen a leak in a 986 evaporator. If any thing, they thinks it's a hose or O-ring. So I'm trying to get some insight into what may be a $5000 repair. Here's the background.

Three months ago, the A/C stopped cooling. The independent filled the system and leak tested it using a sniffer. The shop told me it found a big leak under the dash and the evaporator needed replacdement. It also said the job was too big for because the independent had never taken out a Boxster dash before. The shop said take it to the dealer.

Two months ago, I took the car to a local dealer with a great reputation. The dealer fully evacuated the system and vacuum tested it. It held vacuum for 1 hour with no rise in pressure. Next, the dealer charged the system fully and added dye to see if there was an extremely slow leak that would show up over weeks or months.

The A/C is still cooling fine. But, it makes a periodic wooshing sound now which I told is a sign of a low refrigerant level. I plan take it to the dealer in two weeks to see if the system has lost coolant. The dealer will do this by using a blacklight to look for the dye.

My fear is that they will find that some coolant will have leaked but not see any dye. This would indicate that the problem might be the evaporator. If so, Porsche charges $1800 for the part and 10 - 12 hours of labor. An indepent will take about the same time but charge only $700 for the OEM part. This is a whopping $1100 difference. So here are my questions.

First, are the O-rings between the evaporator and the expansion valve located behind the expansion value and therefore accessible from the front trunk. Or are they under the dash. Given the leak is so slow, I would guess that its a deteriorated o-ring and not a pin hole leak in the metal evaporator. My first thougt is to replace the O-rings and the evaporator.

Two. If the problem is unclear, I am tempted to top of the system using a can of 134a with oil AND stop leak before I shell out $4000 to $5000. Does anyone have any eperience with this, especially with using stop leak?

Three, can anyone suggest how much 134a to add to the system. A Pelican article said the A/C is charged if the pressure is between 25 and 45 PSI. Right now the low side reads 35 PSI. I'm assuming that I should add 134a until it gets back up to 45 PSI.

Thanks for any advice you can give me.

09-24-2012, 06:29 PM	#1
thom4782 Registered User Join Date: Sep 2010 Location: Foster City CA Posts: 1,099	A/C $1100 Question I have a slow leak in my A/C system. The independent A/C shop thinks its the evaporator. The dealer tells me it has never seen a leak in a 986 evaporator. If any thing, they thinks it's a hose or O-ring. So I'm trying to get some insight into what may be a $5000 repair. Here's the background. Three months ago, the A/C stopped cooling. The independent filled the system and leak tested it using a sniffer. The shop told me it found a big leak under the dash and the evaporator needed replacdement. It also said the job was too big for because the independent had never taken out a Boxster dash before. The shop said take it to the dealer. Two months ago, I took the car to a local dealer with a great reputation. The dealer fully evacuated the system and vacuum tested it. It held vacuum for 1 hour with no rise in pressure. Next, the dealer charged the system fully and added dye to see if there was an extremely slow leak that would show up over weeks or months. The A/C is still cooling fine. But, it makes a periodic wooshing sound now which I told is a sign of a low refrigerant level. I plan take it to the dealer in two weeks to see if the system has lost coolant. The dealer will do this by using a blacklight to look for the dye. My fear is that they will find that some coolant will have leaked but not see any dye. This would indicate that the problem might be the evaporator. If so, Porsche charges $1800 for the part and 10 - 12 hours of labor. An indepent will take about the same time but charge only $700 for the OEM part. This is a whopping $1100 difference. So here are my questions. First, are the O-rings between the evaporator and the expansion valve located behind the expansion value and therefore accessible from the front trunk. Or are they under the dash. Given the leak is so slow, I would guess that its a deteriorated o-ring and not a pin hole leak in the metal evaporator. My first thougt is to replace the O-rings and the evaporator. Two. If the problem is unclear, I am tempted to top of the system using a can of 134a with oil AND stop leak before I shell out $4000 to $5000. Does anyone have any eperience with this, especially with using stop leak? Three, can anyone suggest how much 134a to add to the system. A Pelican article said the A/C is charged if the pressure is between 25 and 45 PSI. Right now the low side reads 35 PSI. I'm assuming that I should add 134a until it gets back up to 45 PSI. Thanks for any advice you can give me.