A/C help

[cogcaviz24]

some of you I talked with at the last meet may remember me talking about my son sweating in my car. before the engine blew, the air was really cold. of course in the process of replacing the engine I had to disconnect the lines from the compressor. well tonight I tried recharging the system. after my attempt.... no luck. the compressor wouldn't cut on. i bought a 12oz. bottle and still have a little left. Is there something I missing?

[RobsFieros]

You'll hve to jumper the low pressure switch on the dryer to get the compressor to come on and pull the freon in. After you get 2 cans in it then remove the jumper wire and plug the connector back into the switch and finish installing the 3rd can. It wouldn't hurt to install 1 can of oil charge.

[cogcaviz24]

thanks rob. i'll check it out in the a.m.

[cogcaviz24]

for some reason the compressor is not coming on. i just interrupted on this project so I'll check connections at the compressor when we get back from ATHENS!!! booo! at least it will a little cooler 

[Tha Driver]

It's best to evacuate the system before filling it. Air in the system will interupt the filling process.
~ Paul
aka "Tha Driver"

Each year, more children drown in buckets or pails than are accidentally killed with a firearm.

[cogcaviz24]

argh!! i've gone through 30.oz of freon and the compressor didn't even turn. i assumed that my car has been converted. is it possible it wasn't? i'll let my dad look at it sometime soon

[TopNotch]

You can pull off the connector on the low pressure cut off switch and short the contacts to force the compressor to run, if lack of pressure is what's causing it not to. This trick is often used to get the first can or two of refrigerant in when re-filling the system. On the compressor used on 4-cylinder cars, the low and high pressure switches are on the back end of the compressor. I haven't worked on a 6-cylinder car's compressor, so I don't know where they are on that one.
And if your system has been converted to R134a, it will have different coolant connectors (for re-filling) than if it hasn't been converted. You can't plug an R134a can up to an R12 system.
4-cylinder cars 86 and newer use a V5 compressor. 6-cylinder cars use a DA6 or HR6 compressor. Only the HR6 can be used with R134a.

[cogcaviz24]

i jumpered the lower pressure switch and it still didn't cut on,i could tell the electronics had a load. and from what you described, my car hasn't been converted. i have 2 black caps and i can only connect the refill kit with an adapter

[Tha Driver]

Also, air in the system will make the compressor overheat. You REALLY need to evacuate the system any time you break it open.
~ Paul
aka "Tha Driver"

Success is the ability to go from one failure to another with no loss of enthusiasm. - Winston Churchill

[TopNotch]

If you just put an adapter on and added R134a without doing anything else, you may have messed up the system pretty badly. The general procedure for a successful retrofit to R134a is: Remove (capture if the feds are looking) all the R12. Drain the compressor and accumulator and measure what is drained. Put in a new orifice tube (in a Fiero, it's under the accumulator). Get a new accumulator and put in some Ester oil equal to half what was drained into it. Put the other half into the compressor. Put the system back together with new O-rings. Pull a vacuum on it. If the vacuum holds for a hour, your system is good. Use the vacuum to pull in the first can of R134a. Run the system and put in a couple more cans. It should be running cold now.
There are some additional things to watch. If you possibly can, run the system with a full load of R12 before evacuating and draining the oil. This will get most of the oil into the compressor and accumulator. If your system was oil starved and you didn't drain much out, put more than what you drained in. Most systems require 8 to 11 ounces of oil, depending on system. And some specify the viscosity of oil. I think the HR6 requires 100 viscosity, and I know the V5 requires 150 viscosity. (Refrigerant oil viscosity numbers do not relate in any way to motor oil viscosity.)
There is a drain plug on the side of most compressors. It may not be on the bottom as the compressor is mounted in the car, but you can undo all the mounting bolts on the compressor itself and rotate it to move the plug to the bottom. No need to actually remove the compressor for this (unless, of course, you're replacing it). Then rotate it so the plug is up a ways to add new oil.
New compressors are often supplied dry. Be sure you put in a few ounces of oil and rotate the compressor by hand a little before you install it.
Use Ester oil, not PAG oil, on a retrofit system. R12 systems use a mineral oil that does not mix with PAG oil, but does with Ester oil.