| Strange Issues with Air Conditioning |
Subject: Strange Issues with Air Conditioning by Danspeed1 on 2012/6/12 4:31:14 I am working on the R12 A/C System on a 1987 Corvette with an Automatic. I am doing my best to try and get this done right, but the tools to do it right are harder and harder to come by. This is what I have done so far; System was empty when I received the vehicle. I pulled a vacuum on the system for an hour. To do this I went out and purchased R134A Conversion ports and connected. This way I was able to hookup my 134A Manifold Gauge Set. I have about 6 cans of R12 Left so I want to make sure they don't get used in vein. General Motors states that if the system holds vacuum for 5 minutes its good to go. After 5 minutes I noticed the pressure in the system start to bleed off so I decided to replace all the o-rings with updated green ones, put in a new accumulator, and a new orifice tube. I added 4oz of Mineral oil to the accumulator, 1oz to the compressor, and 1oz to the area of the orifice tube. I pulled Vacuum again. It held at 29 for more then 5 minutes. On most systems I do I will let the gauge set sit on the system overnight. That is the ultimate leakage test. Unfortunately after 1 hour vacuum slowly started to bleed off. However I know R12 is heavy/thick so I decided to take my chances and add 3 cans of R12 which is the recommended amount. I have a 30 year old can hose I used. The refrigerant took about 20 minutes a can with the compressor cycling non stop before I finally made it through all 3 cans and the compressor stayed on and the accumulator and larger line stayed cold. Throughout the induction of the R12 I noticed my line was leaking a little for time to time. Its old. But I am pretty sure 95% of the refrigerant made it into the system. What happened next baffles me. I turned the car off, it cooled down. I restarted it and turned the A/C on. The A/C blows ICE Cold till the car gets to about 190*F then they compressor begins cycling and the system only blows hot air! I couldn't figure out what was wrong. For whatever reason I decided to pull the plug out of the switch on the orifice tube line (forget what its called). The one closer to the bend. Upon doing so the fans kicked on along with the compressor and the system seems to be functioning properly. My questions are as follows. How do you measure the amount of R12 that made its way into the system? Again I am pretty sure its all in there but I want to make sure. Also what is the purpose of the switch I pulled and is it worth replacing? Finally what temperature should the A/C be blowing at for an original R12 System? Thanks, DG |
