I have read several postrs about the AC not being cold and how people have added just a few ounces of refrigerant to make it blow colder. Well I had the same problem; my AC was blowing at 55 while driving.

I picked up a can of r134 and a cheap guage to detect pressure on the low side. I tested it before I added the coolant and it was around 35. I began adding a little and then checking the pressure, and before I knew it the whole can was empty (13 oz.) and the low side pressure was still the same. Why is this?

I know feel that I have over charged the system as it is only a year old. I believe these have a pressure realease valve when the pressures get to high, but I never heard it release. What kind of problems could this cause?

How can I properly release some of the refrigerant? Can I just deflate it like a tire?

 

Also for those of you who have had Ford service the AC, did they tell you the proper pressures for the high and low sides? I am wondering if the low side pressure is constant no matter how much refrigerant is in the system.

 

High side / low side gauges can’t tell you how much freon is in the system. The only way to know for sure is to evacuate the freon into a recovery station and weigh it.

 

I was the dealer the other day to pick up her van. While I was there I told them that my ac wasn't blowing as cold as I thought it should. He stuck 2 temp gauges in the 2 center vents. Came out around 50. He said that they would take all the freon out and weigh it then put in the correct amount and it was covered under the warranty. So now I just have to make an appointment. Might as well let them do it since it will not cost me.

 

there should be a sticker under the hood that tells you how many ounces of ref . it takes. if you add to much it will cycle off on high pressure. 50 deg. isnt bad when it is 85-95 degrees outside you will get better cooling when on the highway because the more air you pass over the condenser coil the better your a/c will run the less air you pass over the condenser the higher pressure you will have and it will not release enough heat through the condenser

 

How often should it cycle on and off?

 

it really depends on the temp outside and the temp your keeping in side the truck . if it is every 5-10 sec. you are probably low on ref. but if you run yor a/c when it is cold it would probably be normal .
the lower the out side temp the lower you refrigerant temp is and it will cycle on low pressure until the refrigerant pressure builds up

 

Well, my AC is blowing cold and not cycling very often; If I did add to much though, what problems could this cause or will it just relieve itself through the pressure relief valve (which has not happened)?

 

I put R134a in mine the other day. It was in the very lowest portion of the "normal" range. I added a can and it brought the level to the top end of the "correct" charge area, and my A/C is MUCH cooler. I figured it beat spending a 1/2 day at the stealership, and I was very careful not to overcharge the system. I think I was the victim of an undercharge from the factory. Anyway, when I step out of the truck, my sunglasses fog up

 

if it runs continious you should be okay you want your pressure around 35-45 psi that should keep your evap above 35deg. a little higher would be okay if it is not cycleing on the high pressure control you are prbably not overcharge . the more refrigerant you put in the lower the air temp you will be getting from the evap/
what air temp are you blowing now?

 

Well, my AC is blowing cold and not cycling very often; If I did add to much though, what problems could this cause or will it just relieve itself through the pressure relief valve (which has not happened)?

 

Now driving it is around 38-44 degress and sitting is around 50 degrees. What do you mean by not cycling on the high pressure control?

 

im not sure if it has a presssure relief valve? if it has too much pressure the high pressure switch should turn off the compressor. go to your local auto parts store and buy the can of r134a with the gauge on it and it is color coded blue ,green ,red ,yellow and run you a/c on max with fan on high and the gauge will tell you if it is overcharge this is the only way to really tell but putting gauges on it . if you over charged take a liitle out at a time and let the system balance out for a few minutes until you are at the proper psi

 

Too much freon creates too much high side pressure under certain conditions. You have a high side release valve, but in addition modern vehicles have a high side pressure cutoff that will turn off the compressor (and hence your air conditioning) before the pressure releases. I don't know the implementation, so it may cut off for a while, or it may cycle like the low side switch.

Even if you did not add enough to cause the high side cutoff to activate, too much freon causes increased high side pressure. Higher pressure causes increased compressor wear and increased fuel consumption.

The only way to tell if the correct amount of freon is in the system is to take it out, weigh it, and put it back in. Pressures vary with changes in engine RPM, outside temperature, airflow, and evaporator inlet temperature and humidity.

Once the freon level is set correctly, if you want your A/C to work better, press the recirculate button. That way you are cooling the already somewhat cooled and dehumidified air. The system still blends enough outside air so you will not sufficate.

 

38-44 deg. i would say you are not overcharged