I just replaced the AC evaporator and the drier in my truck. vacumed in and started to add oil and freon. After adding only 3 OZ of oil and a 1 1/2 cans of freon I had pressure readings of
low side-- 61 and high side 280 . I believe this is too high. Temp would only go down to 58, what do I look for next?

 

I think I remember that A/C will only take the temp down about 30 degrees below ambient. What is your outside temp? I just checked the sticker on my truck and it says factory charge is 2.0 lbs?????

HTH

Ed

 

The outside temp was 80 at the time. The book says 32 oz total charge. each can was 12 oz and the oil is 2 oz a can. So I didn't get a total charge in system. I am wondering if my condensor is clogged up ?

 

Not sure about the condensor, but the orifice tube might be plugged. Don't take much with the holes so small. Since you messed with your system, you could have dislodged some stuff and plugged it up.

Just my .02 worth
Wayne

 

I can pull the temp to 41 or 42 in the duct in my 95 and I leave the temp gauge in it all of the time. 1 and 1/2 cans does seem a bit short to me . Be sure that the condensor is free of trash an has not plugged coils or tubes. I use a fan to simulate air flow in front of the condensor when charging the ac. I like to see a cold line back to the suction of the compressor. good luck Jim

 

If i remember right my 99 uses 2lbs.

I good system should be able to pull her down to around 45. i believe the "comfort" zone is 45-62 deg F

when not running pressure should be the same obviously

when running low side should be in the 30s and the high should be in the mid hundreds, low 200s isnt bad. Pressures will be affected by temp. But more by the humidity than the temp. It could be working harder on a 70f day with high humidity than in arizona on a 90f day

 

I replaced the orifice tube when I installed the evaporator. The old tube wasn't clogged up. I am going to check out condensor prices today.

 

Try running a garden hose on condenser while charging. Your high side head pressure will run a bit high with no (standing still) airflow on it. The water flowing across the condenser should drop your head pressure 50-75 pounds...

Good luck and happy cooling

Gary

 

I started to suggest that but did not think any one would believe me. If you get the system working to factory spects I have installed isolation valves in the heater lines. Most would not believe that but if has helped me out on some marginal systems. good luck JIM

 

studebaker, I replaced my condensor cause it had a hole it it. Got it from Rock Auto. If you want the particulars, PM me.

Wayne

 

Ready to blow my Brains out !!
Changed the evaporator because it was leaking. Changed out the drier, condenser, orifice tube and installed new AC compressor. Checked to make sure right amount of oil was in system. I am still getting an overcharge reading of 61 to 64 low side and 290 high side with only 24 OZ. in system (calls for 32) . Lines coming out of condenser and into drier is sweating, but not real cold. Line going into condenser from compressor is pretty hot. Air coming out of vent is low 60's. Out side temp is 88.
HELP!!

 

okay, let's get this thing fixed. step by step. you said you "vacuumed" it. i hope you are telling us you evacuated the system to around 500 microns. the symtoms you describe are indicative of air in the system. next, you changed out a lot of parts for apparently no reason,that gets expensive fast, and doesn't fix anything. tell me what you are using to pull the system down and we'll go from there.

 

Okay, my evaporator was leaking from leaf and trash buildup. I pulled the dash and changed out the evaporator , drier and orifice tube in the condensor. I then used an old ac vacumm pump and a newer set of 134a guages to vacumm the system down to --29. Did this several times and let the system set with vacumm off and the system held vacumm really well so no leaks. I than started recharging the system, breaking the lines slightly to bleed off air. One can of 12oz was put into system with guages okay. Started putting second can in and that is when pressures started going up and not pulling down(takes 32 oz to fill) . 61 low side 280 high side. Ac lines getting cold and condensation dripping off. Compressor seemed to cut on okay but not cycle off. Outside temp 88. Talked to an AC man and he said that the evaporator was clogged up. Changed it out ------Same results. Several told me it was a weak compressor. Changed it out --- same results. I drove it with the AC on and it was cooling -- but not like it shoulc, didn't have a thermometer to check actual temp. As long as I had speed up it seemed to do much better than at idle. I checked the fan clutch for proper operation as well, thought maybe not enough air going over condensor. Checked okay and engine runs in cool range.
I want to learn to do this right as I have several more vehicle ac's to work on.

 

couple of questions at this point, you say you cracked the lines, this should not have been necessary on any but the center hose. an example, you've got the charging hoses connected to the system with the center hose on the vacuum pump. after your sure it's pulled down far enough to boil out all the moisture, you close both valves. when you disconnect the center hose from the vacuum pump it is going to be the only hose with air in it. when you connect the refrigerant can or drum to the center hose you crack only that hose at the gauge manifold, and only enough to here a little hiss, charging hoses have very little volume. you would then charge the sysyem through the high side until the proper amount has been added. that should be it if the rest of the system is sound. you also said you changed the orifice tube at the condenser, the expansion device should be real close to the evaporator, i'll look at mine and see if i can tell where it is exactly. i'm thinking you may have it in the wrong place. another possible problem could be with the orifice tube itself, if it is not exactly the right size, the system will never work properly. if you have any specific questions just ask and i'll try to help. autozone has books on the subject for around 12 bucks and they can be helpful. good luck.

 

Yes, just cracked the center hose only after closing both valves and let just a little hiss come out. I took out the old orifice tube and replaced it with a new one in same location on the bottom line coming out of condensor in front of radiator. My instructions from guage set says to charge on low pressure side and keep high pressure side closed.