Any a/c guys?

[shaneschevys]

I have a 97 vortec 350 in my 72. I used every thing for the a/c from the 97 except the condensor. I have put 32 oz of 134a & it still doesnt cool. I hooked up the pressure switch on the accumilator. There is a switch on the high pressure side of the manifold that goes on the compressor & a switch on the back of the compressor. Do these need to be hooked up for it to work properly?

[cypress TX 72]

Shane,
Does the system call for 32oz in the 92?
Is the compressor running (Clutch engaging)?
If it is, what are the pressures your getting on your low side gauge.
Since you changed the condenser - the high side would be good to know as well.
If the compressor is comming on then I would say that those switches may be for something else, the key thing is the compressor coming on and the refrigerant flowing.
When you moved it over did you disassemble the lines from the compressor and reciever (accumulator) tank? the reason I am asking is to see if the cap tube is still there and if the screen was clean.

Let me know Shane and I bet we can get you going.
Tony

PS- I'm in houston and I know damn well that AC is as important as the motor itself! - Ive seen on the news that you guys are getting it good as well up there.

[incoma]

I agree with cypress's troubleshooting. clutch engagement, and pressure in the lines are the first 2 I'd check. Then if those are going, I'd look for leaks. 32 oz is a lot of coolant.

[shaneschevys]

Tony
The 97 system calls for 32 0z I have put 3 12 oz cans of 134a in. The clutch is engaging. I am unsure of the pressures my guages are shot they were pegging out the low side & showing 250-300 psi on the high side. I had to dissassemble the system because I had to get the hoses modified but every thing has been covered up. The condensor is the origional for the 72 so I couldnt use the orfice tube.
Shane

[cypress TX 72]

Shane,
If the low side is shooting up past 50 psi and the compressor is engaging - then either the compressor is not pumping or the refrigerant is not flowing. Think of it this way - the high side of the compressor is freon leaving and on the low side its comming back from the evaporator - so if the pressures are equaling out - then it is not being condensed.
When you say you cannot use the orfice tube-does that mean the old one out of the 72 or the new one- because it has to have one to work and it has to be the correct metering for that set up. (or close, it doesnt have to be exact-but it has to have one close)

Gauges are going to be a big help for you to try and pin point the problem
but
If you have a metering devise such as a orfice tube or cap tube in place then the first thing I would try is to dump some of that 134 and see if the pressures go down - while running the truck.
Also, we need to see if the condenser is getting hot, and/or is the suction line (the big line) comming from the accumulator is getting cold.
If the suction line is not getting cold - then I would lead to say that
1.you have either lost your orfice tube or blown it out
2.you have a restriction line the system somewhere
or
3.that there is no orfice tube and the system is just pumping around without metering.

Listen I know it sucks, but if you want to try and fix this yourself I would say that guages are going to be a must- do you have a buddy that may loan a set to you? Cause I am sure after all that the last thing you want to do is have to buy a set of freaken guages.
Man, if you where here, i'd come over and help you.- my wife and kids are away
T

[cypress TX 72]

Also, I forgot to put in the last post.
The pressures that you are looking for are
at start up you should have around 200-230 high side and 40-60 on the low side. then as the truck starts to warm up you will see the high side go up and the low side go down.
When the truck is cooling inside and the doors are shut - you'll get down to about 30psi on the lowside and then the compressor should cycle. At that point your head pressure will be at 250,260, or even 270 depending on how hot it is outside and your fan clutch.
I am pretty sure that that compressor cycles at 30psi it may be as low as 25 or so - but by that point it will be blowing cooooooooold anyway.
T

[cypress TX 72]

Hey Shane, I leaving for the night so I'll check on you tomorrow -
When the cats away the mice will play - hehehehe!
Going to check out the bars and see if I can find me some women trouble.
Good luck Shane.

[shaneschevys]

I was told that the orfice for the 97 is located in the condensor. Where would it be located in the 72 system? Is there any other location where I can put the orfice? The small line is getting hot but the big line is not getting cold. Its slightly cool but not cold. I have a b-day party to go to tomorrow so I will not get to mess with it until the evening.
Thanks for your help
Shane

[ronh72c10]

Originally Posted by shaneschevys

The 97 system calls for 32 0z I have put 3 12 oz cans of 134a in.

Is it possible you've overcharged it? 3 x 12 oz=36 oz of refrigerant

Ron

[cypress TX 72]

The orfice tube is normally in the high side line going into the evaporator - or the accumulator - where the line screws on- inside the pipe itself you should see it in there.
T

[cypress TX 72]

The orfice tube would never be in the condenser, maybe your thinking the drier?

[72LNGHRN]

If it has an orifice tube its normally inthe evaporator inlet Im not sure but I think the older chevys used a valve like a throttling valve similiar to an expansion valve. your low side pressures should run no lower than 20 lbs.thats usually wheen the low pressure cut off switch engages.