Seat Alhambra Climate Failure

Hello very good ..
I have a problem in my Seat Alhambra of 2006. The issue is that the AC does not cool when I connect to cool a little, but then it is disconnected. I connect the load station and I see how the low pressure does not move, it stays like the air removed and the high pressure begins to climb little by little until the compressor is disconnected, as the low pressure does not move I assumed that the expansion valve did not open and that is why it did not go down, I mean that the compressor could not aspire and did not lower it, I changed the valve and the air changed, the air changes, the air changes, the air changes, the air changes, the air changes, the air changes. He missed a little is that at the same time, the valve fell some "oil" liquid but not a lot, I am going around the subject and it only occurs to me that the low circuit this plug, but I am not sure, if someone can throw a cable to me, I appreciate it beforehand, by the way my alhambra has a sponary climate, I suppose that the two circuit work and parallel because the compressor only has two outsake The grill, greetings.