Well I am surely no expert, but I have had cars where the pressure switch starts leaking, and that may be your problem. But you can't just simply replace it - you have to pull out the freon, replace the switch, evacuate the system (fills with air when switch removed), then recharge the system. Not a DIY proposition unless you have the AC gear. But if that is the issue, it is probably the only issue, not symptomatic of something bigger. (But remember, I'm no expert!)

 

there is usually a schrader valve underneath the pressure switch. if the switch has failed and is still screwed into the valve (meaning open state) that could be the cause of your leak. once the switch is unscrewed from the valve, the valve should close and cut off any further freon loss. if you havent lost too much freon, once you put the new switch in, your a/c may operate normally again. but if it has lost too much freon, an evacuation and refill would probably be necessary.


anecdotally, I just changed a coolant temp sensor (not this car) that was leaking from within the sensor itself, so I guess its not uncommon for these types of failures to occur.

 

thanks. seems it sprayed quite a bit inside that I had to clean up. I'll swap out the switch and see how it is, then take it to a pro to refill/check pressures.

I'm hoping the wiring harness is fine. It had enough pressure it blew out that light grey terminal seal on the orange/black wire.

 

I've got a couple PDF manuals - one says to drain refrigerant before removing the switch, the other does not mention it. Both say to wet the o-ring of the new pressure switch with refrigerant oil before installing, tighten to 3.5ftlbs, and follow with a system recharge.

 

I started my car yesterday and white smoke started filling the interior out of the vents. .... Think replacing this will fix it or is the freon getting dumped out of that piece just a symptom of a bigger issue?

Freon is colorless. The white smoke is something else.

 

AC refrigerant leaks most definitely do make a cloud of white smoke. Freon gas may be colorless, but refrigerant lubrication oil isn't, and there are several ounces of it in the refrigerant loop. Consequently, the system makes a big cloud of white smoke when it leaks and makes a mess as the oil gets over everything. (The OP didn't report it, but if anyone put a can of aftermarket R-134a in there, a lot of it has green dye which makes an even bigger mess.) Something in there let loose- could be one of the schrader valves, could be the pressure switch. It's possible the leak was caused by an overpressure in the liquid line, like if the expansion valve clogged and the compressor kept trying to pump, which is exactly what that switch is in there to detect and stop.

You can't replace the pressure switch without draining the system because removing it will open up a hole in the system; if you try, you'll just let it all out anyway. Pulling the sensor will let air into the lines and you'll need a vacuum pump to purge the air from the system and a metered pump to recharge it: most shops that advertise AC service will do this. If it's open for any period of time, you'll need to replace the dryer as well.

This is only a DIY job if you have the right tools (at a bare minimum a vacuum pump, gauge set, and scale), and it would cost more for the tools that it would cost to pay someone to do it for you.

 

The hissing in that area around the switch can be normal for about 30 seconds after you turn off the A/C. It is the sound of the high and low pressures equalizing at the expansion device which is the rectangular box to the left of the switch in the photos. The Freon leaking out there is worrisome. Freon is mixed with oil in the system so if Freon leaks out there can be an oily residue where the leak is.

It is possible that the expansion device failed and put high pressure on the low pressure side which could have blown the seal at the switch or worse. The only thing I can think of that would cause the white stuff at the vents is if a seal or the evaporator leaked and blew out a bunch of old dust that was inside the evaporator box.

If all of the above happened I would be surprised if there is any Freon left in the system.

 

if the issue lies only with the pressure switch failing, wouldnt removing the switch cause the schrader valve to close, thus closing the circuit? then couldnt the switch be replaced with no issue?
not saying there isnt work to do afterwards, but is the above not true?

 

The schrader valve is used to charge the AC system and doesn't serve as a check valve. Once you pull the pressure switch, you'll have a 1/4" hole straight into the AC line; the entire system will evacuate out the hole. It's liquid in that part of the system and will instantly flash-boil as soon as pressure is released.

The schrader valves are under the plastic caps a few inches on either side of that switch. The low pressure schrader valve is standard, but the high pressure valve is larger with a special valvestem that's a pain to find a replacement for and even needs a special tool to remove.

 

I'm a bit of a novice when it comes to car repairs but I really do like learning/fixing stuff myself. So I started my car yesterday and white smoke started filling the interior out of the vents. I pop the hood and there's a hissing coming from an electrical connector going in to my A/C system shown here:


View attachment 139698

View attachment 139706


some googlefu points me to it being an A/C pressure switch. My part doesnt' have a part # on it, but pelican parts did for the previous gen in this pic: http://cdn4.pelicanparts.com/techarticles/Boxster_Tech/97-MISC-AC/images_large/Pic2.jpg


I *think* [this](Porsche Parts A/C Pressure Switch, 911/Boxster/Cayman (05-15)) is the right part for my car, but it doesn't quite look right. Think replacing this will fix it or is the freon getting dumped out of that piece just a symptom of a bigger issue?

Did you solve this problem? Was the switch the issue? Who did you use for recharging your system?

 

Haven't heard anything from boshaus, anyone else have this issue?