I recharged the air today and I can inly get the temp at the vents down to like 56 while driving the air temp here is like 78. I have 28oz of R-134 in it. The sticker says 41oz then I read somewhere that when you convert from R-12 to R-134 that you should only use 80% of the refrigerant which would be 33oz so I am close at 28oz. Does anyone have any suggestions?

 

The chart I found at work says that you need to charge to 32oz or 2lbs, with 7.5 oz of pag oil, when doing the "up"grade. I'd go with that before you start thinking you have problems.
Also if you could get some pressures that would help a butt load while trying to figure out an a/c system.
Justin

 

The low side pressure is about 42 pounds. This truck was converted to 134 two years ago but the ac was never right because of leaves in the hvac box. I got that all cleaned out now I just cannot get the ac right.

 

Pull the cycling switch probe most of the way out of the suction line.

 

Ok dave I will try that but what does that do?

 

It lets the evaporator get colder before the compressor cycles off.

 

Oh ok thanks I will try it but It was not warm enough today to tell

 

Well I pulled it out most of the way and it did not seem to make a difference

 

Make sure that your heater valve is closing and not letting hot water into the heater core with the a/c on.

 

That is good thinking I will check that

 

A friend told me that it could be the expansion valve but I dont know alot about ac systems

 

It's possible your low side pressure seems a little high to me. What is your high side pressure?

 

It has to be pretty close to the 80%, also you need to force more air through the condenser with a big box fan, your fan clutch does not lockup until you have way too much pressure.

 

Yea I wondered about the fan not locking up. How does it know when to lock up by temperature I guess. today I checked a few things and here is what I found. The heater control valve is not working at all(Thanks 14Racing). I picked up a new one today but I have not put it on yet cause of the rain. I also checked the pressuers with real gauges today and the low side was at like 28 or so and the high side was at like 305. I know 28 is too low and 305 is way too high so I just picked up an expansion valve. I have already replaced the drier so I hope that this expansion valve fixes it. I am going to try to put it all together tomorrow. Thanks for all the help you have all given and will continue to give that is what makes this place so great.

 

Ok so I went out in the rain like an idiot and changed the heater control valve and now I got the temps down to 46 at an idle and 40 going down the road. But I know I still gotta do something about the pressures. I hope that my buddy is gonna evacuate the system tomorrow so I can change the expansion valve. Then we will charge it from a vacuume. Thanks again 14racing good call!!!!!