Automotive Air Conditioning Information Forum

I have a 2000 Dodge Dakota that I am trying to get the A/C working on. I had to change the orifice tube and the dryer, so I had it evac.ed and did the work. I then pumped it down and it held good vacuum, no leaks. I then started to fill it with R134a and got some interesting pressures on my gauge set. It needs 2.6 pounds for a full charge. I put in the first pound. The compressor started to cycle on and off in about 5 to 10 sec intervals. With compressor on, low side goes to 50 to 55 psi, but has gotten as high as 70 psi on several cycles. The whole time, compressor on or off, high side stays at about 85 psi. Ambient temp was 93F. With the AC off, low is at 100psi and high is at 90psi. My question is, seeing these pressures, and the compressor cycling with 1 pound of R1134a in, should I keep going with more refrigerant OR does what I am seeing indicate a problem in the system. Thanks!

Disclaimer - I know a bit, but I am NOT an AC expert.

I have to ask: did you read those pressures WHILE the low pressure side refrigerant valve was open to the refrigerant container? Because if so, I never pay any attention to readings unless the low pressure line is closed to the refrigerant source, and then only at about 2000 rpm.

So I think you need to add the remaining refrigerant, and use a fan over the condenser, or even mist the condenser with some water to fill the system to correct capacity.

NEVER add any sealers or refrigerant containing sealers.

Cusser wrote:Disclaimer - I know a bit, but I am NOT an AC expert.

I have to ask: did you read those pressures WHILE the low pressure side refrigerant valve was open to the refrigerant container? Because if so, I never pay any attention to readings unless the low pressure line is closed to the refrigerant source, and then only at about 2000 rpm.

So I think you need to add the remaining refrigerant, and use a fan over the condenser, or even mist the condenser with some water to fill the system to correct capacity.

NEVER add any sealers or refrigerant containing sealers.

Correct.

you can place your R134a cans in hot water to get it into the system. You need to get a full corret charge into it before you can evaluate its performance.