Help with 1976 Town and Country AC

[desotogeorge]

Hey guys, I am hoping one of you have had this problem and can point me in the right direction as to how to fix it.
The AC on 76 was blowing very cold, then it did not, then it did, now it has stopped again. The funny thing is that the compressor is engaged while it is not blowing cold so I do not see how it can be low on gas or the low pressure switch would stop the compressor.
When it is not blowing cold there is little or no strain on the engine, when it is blowing cold it REALLY drags a LOT out of the engine and it stalls all the time at idle ( ok mayge the carb is to blame but it really drains a lot of power )
I am new to these later model mopars, is such a big power drain normal?? I do not remember having this sort of trouble when I was driving them in Canada etc a few years ago.
Any suggestions, and input appreciated, George.

 

[Mr C]

Is it icing up on you?

 

[mrfury68]

Expansion valve sticking?

 

[traintech55]

Without a gauge manifold set it would be almost impossible to troubleshoot. I would say you have a clogged line, but where? I would take it to a shop.

 

[commando1]

Always Question #1:
Manual A/C or ATC Il?

Question #2:
Coverted to 134A using OEM R2 compressor?
Was OPR valve removed?

Most shops know nothing about the OPR valve needing to be removed.

 

[DC118us]

 

[1978 NYB]

OPR valve is still in mine and I still get 38 degrees at the center vent.

 

[commando1]

OPR valve is still in mine and I still get 38 degrees at the center vent.

And I envy you everytime you rub that in...

 

[saforwardlook]

OK, i'll bite. I am aware of what EPR valve means, so what does OPR valve mean?

 

[thrashingcows]

I;m not sure but going to guess OPR stands for Over Pressure Relief valve....?

I converted the A/C system in my 70 sport fury with some Freeze12....all original with no change to the system, RV2 compressor, even the drier was still the OEM one. That system would frost the front window in the middle of summer.....never had AC that cold in any other vehicle since.

 

[commando1]

OK, i'll bite. I am aware of what EPR valve means, so what does OPR valve mean?

My apologies for fat fingered typing. It is indeed EPR, not OPR.

 

[desotogeorge]

Guys, more imformation please, why does the over pressure have to be removed?? and where exactly is it?? I know where the low pressure switch is.
Yes it has the new gas in it and so far I have checked the expansion valve, seems ok. Pulled the valve that is in behind the low pressure side pipe in the compressor, it was stuck in there fairly hard, is now free to move if it has to ( is that the high pressure valve?? ) we are having trouble getting it to take gas. My Ac guy does not have a 3 hose deal just the normal 2 and as far as we can figure it you have to apply the gas to the low side and the pump head at the same time?? that is referring to the workshop manual.

 

[commando1]

My Ac guy does not have a 3 hose deal just the normal

Found the problem.
Get a real A/C guy. You're wasting time and money with your present joker.

 

[traintech55]

Found the problem.
Get a real A/C guy. You're wasting time and money with your present joker.

First, you did not say that the system was opened before. Did he evacuate the system, (pull it down with a vacuum)? If not trying to recharge will not work correctly, for reason #1, for #2 the evacuation process will tell you if you have any further leaks in the system. Take you car to a reputable shop.

 

[desotogeorge]

Guys, yes it has been vacumed twice and no leaks.
Don't forget I am in Australia and an old Mopar system that uses 3 hoses to gas is a strange thing to a modern AC guy. He is putting in the effort and has taken the manual home to read before we try again. We get the impression that the valve in the compressor head locks if you do not fill with even pressure to the low side and the compressor head inlet fitting ? but if I could have more imformation on why that High Pressure Valve should be removed and where to find it would be great