If you have had a problem with your Porsche A/C system that will need to be dealt with before you attempt any kind of vacuuming of the system. Once that is all in order, it is a short job to ensure it is all back in perfect working order.
What Do I Need?
Before you start you will need to have a vacuum pump and a standard manifold gauge set. These are easily obtainable form your quality OEM parts distributor.
Before you start the pump, the first thing you will need to do is establish which side of the system is which. By that, I mean, which is the high-pressure side, and which is the low-pressure side or suction side. This will then allow you to connect the gauges correctly. The correct way to do this is to attach the blue hose from your manifold gauge to the low-pressure side and attach the red hose to the high-pressure side.
Connect The Pump
Next, you will need to connect the vacuum pump to the center hose yellow line, but make sure that the low side and the high side valves on the manifold gauges are closed. When you have checked that the valves are closed, and the hoses are attached correctly you can then switch on the pump.
Open The Valves
Once the pump has been started you can then open the high side and low side valves on the manifold gauges. Although the full running time should be anywhere between 30-60 minutes, it is best to start by just allowing the pump to run for around 10 minutes or so at first. You should then turn off the high side valve. Next, check the reading on the low side gauge. Wait a few minutes and look at the reading again. If all is well it should remain the same. If it does remain the same, then you are good to continue pumping for the allotted time. However, if the reading has lowered then you have a leak somewhere and this needs to be addressed before you continue.
How Long Should The Pump Run For?
It is recommended that you should allow the pump to run for about 30 minutes unless your system has previously had a seized compressor or something equally serious, in which case you should allow the pump to run for about an hour. When the time is up you need to close both valves and turn the pump off. Next, remove the yellow line from the pump.
Your vacuum pump should pull deep vacuum through. This is because water does not boil until the level of the vacuum is under 1,500 microns. A deep vacuum is under 750 microns. The best level of vacuum is around 200-300 micron or lower.
Once you have vacuumed your Porsche air conditioning, you will once again be able to relax in the cool interior, safe in the knowledge you have done a good job!