AC blows warm air at idle, even with the heater shut off valve. Start driving and get the rpm's up just a little and ac blows nice and cold. Air gap checks out ok, the cheap guage that comes on the can says my pressure is good.

I don't have a real set of gauges to check high and low side pressure. I've also heard it might be a restriction in some orifice. Can anyone tell me where this orifice is? Any other thoughts as what my problem might be?

 

too low on freon will do the same thing...i just had to refill my big truck cause of that..

 

That's why I bought the can with the little cheap-o gauge on it. Maybe I read the gauge wrong?

 

The orifice (CCOT) is in the small tube in the inlet of the evaporator core. Bottom line. You can feel the lines and also tell if you are low on freon. The outlet and inlet line temps of the evaporator should be near the same when the system is full. Is any of the lines frosting up? Call me, if you have any questions.

 

could be..i dont trust them gauges...i think the can needs to up side down for them to read right...but i still dont trust them...did it take any or did you try??

 

I haven't looked to see if anything is frosting up. Guess that's a good job for today. Thanks for the info Roland. I may be giving you a call later when I look into this.

 

Glad you posted that, I've been searching for the info I read about that orifice this morning and having no luck. Mines having same problems. If I knew how to work a dang computer, I'd have an encyclopedia of PSD info all nice and categorized and could have posted that "orifice" info. But....

 

Don't know if this helps you or not, pretty good read. Post 23 is what I was searching for this morning. Hope I did the "link" right.

https://www.ford-trucks.com/forums/9...uit-today.html

 

lack of air flow will also give you fits. look down between the intercooler and the radiator. if its packed with bugs, dirt, dog hair and such it will slow the airflow enough at idle that the A/C won't work. the only way to really get it clean is to pull the radiator and pressure wash it. I've seen vast improvements in A/C performance by doing this.
hope this helps

Barney

 

Oh my. Just took a peek and it's quite evident the PO was a West Texas rancher. It's absolutely filthy and red. We don't have red dirt in my neck of the woods.

 

Thanks Barney. I ran into that before and since I've been in the hayfield the last couple of days, that was the first thing I checked.

After talking to Roland he suggested I rev the motor and watch to see if there was a pressure drop with the rpm's up. My helper was busy so I revved the motor, then ran around to look at the gauge to catch the tail end of the movement.

Then I got to thinking, I was going to need to catch the pressure reading when the AC was blowing warm. Well I finally did and it pegged the gauge past 80. Rev the motor so it started blowing cold again and next time at idle it was back down around 30.

So pegging the gauge tells me there is some sort of restriction in there. In a closed system, the only thing that can cause a restriction is something that has come apart or come loose from where it's supposed to be, right? Am I missing something?

How hard is it to change out a compressor? What other parts need to be changed at the same time? New screen & o-rings I'm sure. Does some sort of dryer or additional filter need to be installed to catch any other pieces floating around in the system? Suggestions on good places to get the parts? Any one brand better than the other?

Or should I just take it apart and clean it and see how long it lasts?

 

Is the compressor running when the guage goes to 80?
You really need a set of gauges you so you can read the hig side

 

I wished you would have called me,I have a set of gauges and we could have dug into this together.Muchless,I would have brought Truman with me.

 

Barry,
I'm sure Chris will get with you after reading your post. We talked for a while this evening and he said he was going to look for someone with a set of gauges to check both low and high pressures.

 

With the a/c on high and the doors open, the compressor should stay running all the time. When its cycling, its usually low pressure on the low side.

This site has a nice explanation of what the high or low readings could mean. Troubleshoot Automotive Air Conditioning Problems