This has been an ongoing problem. Acouple of years ago while sitting at idle for a minute or two the A/C on my 03 f-250 would blow out the refrigerant until i turned it off. Took it in and they told me it was the fan clutch, so we replaced it, recharged the a/c and off i went until i got to a stop light where it blew out the ref. Took it to another shop, and he said i wasn't getting enough air flow, so we put an electric fan, and that worked until a couple of weeks ago. Finally got a chance to take it in and put a new condenser, compressor, and dryer on, and it works but it is still building way too much pressure on the high pressure side(350-450psi). With everything new what could it be?

 

Does the psi come down?. That doesn't sound like its overpressurising.did you change the orifice tube when you did everything else?.

 

Yeah we did. the orfice tube was full of gunk, so we blew all the lines out. It is frustrating, as long as i am moving down the road it is fine and cold but i am afraid to sit at a stop light and have it blow the freon.

 

What do you mean by blow out the freeon? Are you saying it loses charge? Or just that it starts to blow warm? What are your low side pressures doing?

 

Was the wrong kind of oil / sealer / charge used in it?

If so, complete clean out, solvent wash out lines, etc. before you even try to fix.

Most parts like receiver dryer, etc have to be replaced if that is the case.

 

Lack of air flow thru the condensor is the normal culprit for hi-side press. if it isn't over charged. However your hi-press. cut out sw. should stop the compressor before it blows refrigerant thus the common cycling that you hear. A plugged orifice will also cause hi press. but once again the hi-press. sw. should catch it.

 

texans : The freon blows out the pressure relief valve (makes a buzzing sound). Then it will blow out warm air if i don't shut the a/c off right away, before it loses all of the freon.


gearloose1 : I saw a bottle of PAG 46 with the UV dye in it. I hope it is the right oil.

69cj : The high pressure switch is the one thing i didn't replace and that seems to make sense. where is it? is it on the dryer?


Thanks everybody for time and info. I am a big boy and NEED that a/c.

 

Do you know what your low side pressure is? Sounds like you still have some sort of restriction in the system to me. Might need to evac the system and pull the orfice tube again. The only part of the system you didn't replace would be the lines them self and the evaperator. If you didn't get the lines really clean then you may have pluged the orfice again.

 

Did you vacuum down the system before you recharged it? Air in the system will cause higher then normal pressures.
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What are you low side pressures? It may be simply overcharged.
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How much oil did you put in it when you changed everything out?
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If not overcharged, and you didn't vacuum the system down before charging I would tear it apart and check the orifice tube. If there is anything on it I would flush the system with AC flush.
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There is an AC section in this forum. Those guys really know the AC stuff. They have helped me a lot when I needed help.