OK, I pulled out the evap.,cleaned it installed a STV update kit, flushed the evap,and cond, added 11oz. ester oil added 48 oz. of 134 the system holds 60 oz. r12 in my garage 90 degree day went from 70 degrees to 48:hurray: my question is should i get another can and add a little more 134?

Finally, You got it going you way. :thumbsup:

I would not add any more. If the system held 60 oz of R12, it will take 50 oz. of R134a. You got 48 in. It will do better than 48* riding down the highway.

Hey Dan, Jim E-mailed me some pics of your chevelle with the new wheels VERY NICE!!!

Scott, I think I"m having the same problem. My A/C currently blows at 70*. Pulled out the evap, nothing clogging it, etc. I rebuilt the system back around Dec and it was working very well. Now on a 95º+ Day it only seems to blow about 70º. System has no leaks, compressor is running good, and the inlet tube to the evap is nice and cold upon touching it. I don't have any gauges to check the pressures, but would this sound like its low in 134a? I don't want to add any thing before i can check the high/low side pressures. And congrads on getting yours to work :)

If your STV "update" kit converts your system to a clutch-cycling system, and you have the A-6 compressor, then I would re-think that. The clutch on the old A-6's were never intended to be cycled on-off frequently and repeatedly. The R-4's are.

Well my compressor seems to be cycling ok. But I know I've heard that before

wreckfixer,
It's true that those clutches weren't meant to cycle frequently, but I've never seen one fail from it. Many dealer add on systems cycled A6 compressors via a thermostat. The A6 in my 78 Elky is thermostat cycled also.
I don't like the update kits either as they are a "downgrade" to the system, but rebuildable STVs are getting hard to come by these days because the cores have often spent years open to air and are corroded.
If it works for you, that's great.

69307/350Chevelle
Clamp off or disconnect your heater hoses and see if it cools better. If the evaporator tubes are both cold, the system is very close to being "right". You may have some reheating going on.
Also make sure the recirc door(s) are working correctly to bl,ock off hot outside air.
You really need to source a manifold gauge set. Assessing the system without it is just a guessing game.

Isrx101, I have disconnected the heater hoses already, thats what i first thought of after researching. All the ventilation doors work correctly. besides the heater core, where else can warm air enter from? Does the hood cowl let outside air in thru the same way? The lower inlet tube of the evap is cold, the upper outlet hose is warmer. And yeah, for $55 I think I'll invest in some manifold gauges. I took a thermometer to the center vents with the fan on full blast, ran about 70º.

Isrx101, I have disconnected the heater hoses already, thats what i first thought of after researching.... The lower inlet tube of the evap is cold, the upper outlet hose is warmer....

Oh, you're undercharged or don't have enough airflow over the condenser. Most likely undercharged if it doesn't cool better at road speed.
If you had gauges, the high side would probably be too low and the low side may even pull into a vacuum.
Still have a POA valve or an eliminator?

I have the Eliminator on there. I still do have the POA, I really should get that retrofitted. I have duel electric fans pulling air fast enough. Today was about 100º. Someone said that you'll get about 30º less than the ambient air temp for our systems, and it was blowing at 70, so maybe its just that? Or maybe it is just undercharged?

I have the Eliminator on there. I still do have the POA, I really should get that retrofitted. I have duel electric fans pulling air fast enough. Today was about 100º. Someone said that you'll get about 30º less than the ambient air temp for our systems, and it was blowing at 70, so maybe its just that? Or maybe it is just undercharged?

The cabin temp should drop about 30*. Your vent temps should be colder.
It really sounds like you're undercharged, but the switch on the POA eliminator should be cycling the compressor off if that were the case. Is it?

Yes it does cycle on and off, cycles less after its colder. I recently resealed up the A/C evap box, had a few gaps in the gasket. That helped a little.



--Was able to get my hands on a gauge set. The system is charged, but just enough to get it cold, but another can of 134a in and it blows way cooler now, thanks for the help :):hurray: