I am trying to get the A/C system operable again in my 73 Mustang. During my restoration of this car I have replaced all of the o-rings, the drier, and had the dash apart for a heater core replacement. When I bought the car 1 1/2 years ago the A/C system did function although barely blew cold. I had only tried it once and can't say that it was in good or great condition before because I really don't know. When I had it discharged 7 months ago it only had 0.5 pounds of freon (I estimate that it holds 2 lbs).
Yesterday I took it to have it charged at the shop that discharged the system. After keeping my car all day, they told me that there is a problem. They said the system cycled (compressor) on an off fine at first but then immediately went to cycling on an off immediately building up 300psi at the guage. They told me there was a "blockage in the system or lines" and that the compressor may be to blame as it could be worn out and pushing metal shavings into the lines. I had them discharge it and brought it home.
Today I disconnected the lines from the compressor and shot a little air through--air goes all the way through the system and my understanding is that air molecules are larger than R12 molecules so I think I would have found a blockage if there was a constant source of blockage. I did not do any testing or blow anything through the compressor. I did notice a small filter/screen in the head of the compressor (I think it is the suction side) but can't figure out how to get it out to check it.
The only things I can think could be the problem are:
1) The screen in the head is clogged (How to remove?) Is there another filter in the lines somewhere I missed?
2) The expansion valve may be at fault. From what I understand it controls pressure of the freon as it exits the evaporator. But I think it would take a while for that to become an issue. (How to test??)
3) The thermostatic switch is not functioning properly and is causing the system to cycle due to electrical malfunction (how to test???)
4) The compressor is shot and really is blowing metal through the system (any way to confirm????)
5) I just wasn't meant to stay cool in sunny Southern California. (no comments!)
Any help or answers to the above would be greatly appreciated.
Yesterday I took it to have it charged at the shop that discharged the system. After keeping my car all day, they told me that there is a problem. They said the system cycled (compressor) on an off fine at first but then immediately went to cycling on an off immediately building up 300psi at the guage. They told me there was a "blockage in the system or lines" and that the compressor may be to blame as it could be worn out and pushing metal shavings into the lines. I had them discharge it and brought it home.
Today I disconnected the lines from the compressor and shot a little air through--air goes all the way through the system and my understanding is that air molecules are larger than R12 molecules so I think I would have found a blockage if there was a constant source of blockage. I did not do any testing or blow anything through the compressor. I did notice a small filter/screen in the head of the compressor (I think it is the suction side) but can't figure out how to get it out to check it.
The only things I can think could be the problem are:
1) The screen in the head is clogged (How to remove?) Is there another filter in the lines somewhere I missed?
2) The expansion valve may be at fault. From what I understand it controls pressure of the freon as it exits the evaporator. But I think it would take a while for that to become an issue. (How to test??)
3) The thermostatic switch is not functioning properly and is causing the system to cycle due to electrical malfunction (how to test???)
4) The compressor is shot and really is blowing metal through the system (any way to confirm????)
5) I just wasn't meant to stay cool in sunny Southern California. (no comments!)
Any help or answers to the above would be greatly appreciated.