I read for sale car adds saying "ice cold air". How can I make my R134a system blow ice cold air?? Right now it doesn't work. My AC started out running sorta cool then after running it for a couple of weeks progessivly the air got warm. The compressor comes on. The sytem pressure is 80lbs. which I think is way too much. Would just a recharge do the trick? Why do AC technitions use a vacuum pump on the system?

 

Did you/they do the conversion to the system for the new refridgerant? I don't know what needs to be done, but I do know they need to do something to the system to hold the new stuff.

That being said, you possibly have a leak somewhere?

 

The previous owner did the conversion or had it done. I don't think I have a leak since the system has 80lbs of pressure in it.

 

Too much pressure will also cause your A/C to not work. Check the pressure again at 2000 rpms and see what it reads, if it's too high/low, then while driving you'll get no cold air at all. Needs to be within spec for the system to work.

 

80lbs running, or not? If not, then that doesn't really mean much. What is it with the compressor engaged?

 

All cars for sale will say "ice cold" air conditioning. That means nothing. It would be like the car magazines saying "fast car" instead of running the numbers on them.

A/C guys use the vacuum pump to suck the moisture and air out of a system when they're servicing it. Air itself won't compress like the refrigerant will.

You'll need a psi reading when the car is running. MAX A/C, cold, fastest fan speed.

 

Like he said with the Max A/C, cold, fan on high, but am a wrong in saying hold it 2K rpm's? That's how I've always done mine, and it works like a charm....... does it make a difference?

 

I've never heard of doing 2K RPM. But I suppose it wouldn't hurt. Probably seems a bit more real world.

 

Yes, it does make a difference. Automotive AC systems work there worst (or are the least efficient) at idle and when parked. THe rpm is too low to drive the compressor enough (combined with the lack of airflow through the condensor) to develop the same cooling effect. Most service manuals say to run the test at 1500-2000rpm. If you stick a thermometer in the vent, on many systems you will see the temp drop a few more degrees when raising the idle rpm.
One other note for testing for these cars.....if you have the single fan setup where it only comes on via the high pressure switch, then pull the harness connector off the high pressure switch while testing/charging your system. You will get a more accurate reading of how effective the system is cooling with airflow through the condensor.

 

Where are you measuring this pressure? system running or not, high side, low side????? If that is the low side with the system running, then don't use the system until the problem is identified and fixed. That is too high and could damage the compressor.

You really need to get a manifold gauge set on there and report back to us what the high and low pressures are with the system running. That will give us a much better idea of what is going on.

 

Well the person I bout my Z28 from has my A/C in parts what I could really use is is pix of where the hoses go I cant find anything on line. I have an 83 Z28 305 5.0V8 can anyone help me?

 

Look st 3rd gens 4sale on ebay. Lots of engine bay pics.