Hello All
Just completed retrofit last week. Changed oil in compressor, replaced dryer and expansion valve as well as all inline seals. A friend brought his gages over and we did the following.
pumped out system for over an hour at about -19 Lbs vacume. (I think it was in lbs and not inches.) We then introduced one can 134a into system and then turned engine on. Whith ac on full power we put in enough refrigerant to get the system to about 42 degrees. The next day wife said car would cool to 60 degrees. (I left temp gauge in vent and that is how she knew.)Since I did the work I assumed that I had left or creatted a leak in the system. By the way the system did not work before and the service people said was leaking at dryer which I replaced. We put the gauges back on but the pressures were as we left them. No leak. We added some more refrigerant but that did not help. we then evacuated the system and tried it again. Same results.will only cool to 60 degrees.
First question. How does the expansion valve work? The mechanic I am working whith only has expierience with 1 tube systems as opposed to the 2 capullary tube system this has.
Second question. In between evaporator and dryer (actually on a TEE of the dryer) is a device that may be a valve of some sort. What is this device?
Thank you all very much for help on this matter as well as past and future issues.

Joe Scott
Atlanta GA

You said you pulled 19 inches of vacuum on it. If this was not a typo then you either have a leak or the vacuum pump you used is worn out or something. You should evacuate to at least 24 in and after evacuating monitor vacuum (with pump off) for at least one hour to make sure it's holding.

Justin B.
83 Turbo

I know a great fix for this--take it to an AC shop and have them fill it. You're entitled after all that work, and they'll know how to do it. Also, I find that with my conversion I have to have all vents shut except for center 2 to get maximum cooling.
-Kurt

Either it is way undercharged (freezing the evaporator) or, more likely, it is overcharged.

The volume has to be extremely accurate. I don't know what the 88 240's R12 volume is. Charging by pressure is much better though. High side: 2.2 to 2.5 ambient temperature entering the condenser is a good figure, and stay on the lower side of that range for best results. That should help.

Note this is just information to use as a guide.
--
Chris Herbst, near Chicago.

I am not an expert on A/C issues, but what little bit I do know it sounds like maybe you have overcharged the system. R-134a should be 80% of what a R-12 would be. So find out what the charge is suppouse to be in psi. Hook up the gauges and add R-134a until you reach 80% of the R-12 value. Being a amatuer a/c dude I have tried in the past to charge systems by looking at a thermo in the vent and it is not a good way to go. Because I am such a cheapskate, and will not fork out the money for the a/c gauges, I calculate how much regerariant I put in.

Good Luck

sdol
Thanks for the reply.
I have read in many places that less goes farther with 134A. I should have mentioned that the third time we charged it we tried a little at a time all the way up to full. I dont have money or the know how for gauges myself so as far as the pressures on the low and high side i was relying on my mechanic to tell me. Have you done an 88 240? I do not know if they are different by years. and if you did, do you remember how much refrigerant (by cans) you used?

thanks much
joe