On my 93 Ram the A/C was not cooling very well and the Compressor cycling in &amp; out all of the time. So I decided to retrofit the system since it is 10 years old I changed out the Accumulator &amp; Expansion Valve and the other O-rings to go along with it. I flushed the system the best I could then I vacum the system down for one hour and it pulled down to <br>-26. I added the Ester oil and then charged the system with 1.9 pounds of R134a. Well now the compressor does not cycle at all. The head pressure is running at 325 and the low side 22. The air coming out of the vent is running around 44 degress, the intake air at the floor is approx 75 degress. Does this sound right or is there a problem somewhere that I'm over looking? A/C is not somethign I deal with all of the time. So any &amp; all suggestions or information are welcomed.

 

134A and R12 run different head and suction pressures. Try going to a parts house and ask to about the 134A gauges, most good gauges will have a scale for R12 &amp; 134A, see where the 134 falls on the gauge in relation to the R12 for the temp you want, adjust accordingly. I THINK that the systems are not charged at idle but a higher RPM, I may be wrong, maybe someone will chime in and help. What was your outside ambient temp???? Will it cycle on Max AC??

 

We did everything from a R134a A/C station. It does not cycle on A/C or Max A/C..

 

One thing I saw was that you only pulled it down to 26&quot; hg. That's not really a deep enough vacuum for AC. My dad and I always let the pump pull down until the gauge hit 30&quot;hg, and then run for another hour or 2. 30&quot; CAN NOT be achieved here on earth, but that's what the gauge would read, so he also added a micron gauge. 26&quot; won't even start to remove the moisture that has gotten in the system. 134A is cheap, I'd try again and let the vacuum pump suck till it can't suck anymore. Did you also drain the oil from the compressor before you added the new ester oil? They say that if the 2 are mixed, you get something like JELL-O in the lines and if this happens, UH - OH

 

26 is the lowest the vacum would pull it down. It ran for a hour and it pulled to 26 with in the first 30 minutes or so. I didn't pull the compressor. I didn't pull the compressor on my other truck and it works fine...

 

you might try taping a good digital thermometer to the suction line at the evaporator. run engine at 1200 rpm. gas the system til it gets cold and starts to warm up then remove gas til it cools down again. i have done my personnal vehicles this way and they spit snow *****. this is not the way the manuel says do it but it worked for me. 34 to 38 degree air is common. 4 diff. mopars 76 model through 90

 

[quote author=GaCamper link=board=9;threadid=14620;start=0#137116 date=1052707999]<br>26 is the lowest the vacum would pull it down. It ran for a hour and it pulled to 26 with in the first 30 minutes or so. I didn't pull the compressor. I didn't pull the compressor on my other truck and it works fine...<br>[/quote]<br><br>I agree with pumpdaddy. If 26 was the lowest it would pull it down over an hour. I would evacuate the system and charge with nitrogen and start looking for leaks. With the valves closed and the system pulled down to 26, did it ever move off of that number?

 

We think the vacum system we used is not pulling hard enought. We turn the valves off and let the system sit and the gauge never did drop. We where talking today and I think We may of over oiled the system. So I think we are going pull pull the system back down an flush everything and start all over again......Any suggestion on the best way to get all of the oil out of the system?

 

Most of the oil will be in the compressor, but there will also be small amounts in the system. One thing I forgot to ask you was did you also replace the dryer? I would also do as Monty said, blow the charge and then fill with nitrogen and bubble soap all the connection, don't use dishwashing liquid, the AC shops sell a good bubble gook to use. How much oil did you install? The last retro I did, I just poured it into the compressor before installing.

 

The bubble solution pumpdaddy is refferring to is blue in color and is called &quot;Leak Detector&quot;. Real good stuff, I keep an extra bottle in my toolbox at all times. Im just going by the class 8 systems here, but, usually the piston type compressor (rotary on yours) is prefilled with a couple ounces of Ester Oil. Before charging the system, I usually put 1 ounce of Ester in the lines and then charge the system. These numbers may not help, but, as you see, a little dab will do ya.