Hey A/C guru's. A/C works but no cold air?

[agp23109]

So I just replaced the a/c compressor and lines. System worked great for a short time. Recently when I turn the a/c on there is very little change in air temp. I already installed a heater core max a/c bypass so that is not the problem. The line going into the evaporator under the dash is ice cold so it seems to be working. I have a factory service manual and checked out the diagram for the air routing through the duct work. I did not see any obviouse doors listed in the diagram that could be sticking causing the air to bypass the evaporator but maybe I missed something? Any thoughts?

 

[timothyr1014]

could you be freezing the evap coil?

Does it work after its been sitting for awhile and then stop?

 

[Black dawg]

blend door blocked? very common on that body style.

 

[agp23109]

I don't think it's freezing the coil as the compressor cycles regular and it is never that cold to begin with. As for the blend door sticking, the air will get hot if I disconnect the heater core bypass. I am assuming the blend door is controlled by the hot/cold dial or is it automatically vacuum actuated when the a/c is on?

 

[Diesel JD]

Did you replace the condenser and evap cores when you did the compressor and lines? How about your orifice tube? Otherwise I'd say maybe you have a leak and you're out of refrigerant, or maybe you could be out because your high pressure relief valve popped. I'm in the midst of the same job, almost done, and I would be pretty upset if for some reason it didn't work right after I was done so I sure hope you get it figured out.

 

[cm1hedge]

Sounds like the orifice tube is plugged.

 

[agp23109]

The evap and condensor was not replaced. The orfice tube was replaced but I guess there could be crud in the system that blocked it. This was the series of events. I replaced the compressor as when I purchased the truck it was broken. At that time the orfice tube replaced and everything replaced that needed to be so it could be switched over from R12. Worked great. Then stared getting weaker and weaker. Inspected the system and found one of my hoses was leaking. Tried one of those auto parts store R134 cans and blew my high pressure relief valve. Replaced both lines for the heck of it which included the valve. My buddy has an auto repair shop and he had his guys do it. Went and picked up the truck and they said they just finished the job and it was blowing nice and cold. I trust these guys as I have dealt with them before. It was cold outside and I was in a hurry as I was leaving on a trip so I didn't check the AC. I hooked up the trailer and headed into towards Tahoe at which point I discovered the AC went from hardley working to almost not at all. I know I should have checked the AC when I picked it up but I was in a hurry and it didn't matter if it worked or not as I needed the truck regardless. I was thinking that since the evap line from the outside was cold that it must be getting cold inside so I figured it was a blend door or something inside the HVAC routing system. I am no AC guru and hate to take it back to my buddies shop as he did it as a favor and is about 45 min from where I live.

 

[DragRag]

Sounds like the orifice tube is plugged.

most likely.

 

[Simp5782]

If the dryer is not getting cold then its more than likely the orifice tube.

 

[Black dawg]

the blend door is controlled by the hot cold knob. if the orifice tube were plugged the evaporator wouldnt be cold.

 

[Diesel JD]

And if the orifice tube is plugged your compressor is probably dying a sow death or you didn't get all the crud out of the condenser and evap core when you did the job the first time. I know from experience, all too well. Gotta replace them and the orifice tube and maybe the compressor again. I hate to recommend that job to anyone.

 

[OLDBULL8]

The line going into the evaporator under the dash is ice cold so it seems to be working

Don't you mean the line (large line low side) from the evaporator to the filter/dryer is cold? The small line (hi side) should be warm. How is your vacuum? That operates the doors.

 

[punkmechanic]

I think your issue is in the "cheap parts store r134" most or all of those have a " leak inhibitor". Its a gooey snot that will trash everything in your ac system, incluing equipment used to evac your system for service.

Go to your local ford parts house and get some ac ststem flush, flush the entire system as per the instructions. Replace the orphice tube and dryer, charge with real r 134 and i bet your ac will freeze you out of the cab

Punk

 

[agp23109]

Thanks for all the sugestions. I will flush the system and replace the orfice tube and go from there. Thanks for all the help!

 

[agp23109]

Sounds like the orifice tube is plugged.

Thought I should update this post since it's finally got warm enough for me to take care of this. Thanks to all who said it was the orfice tube, you were right on

Got it taken care of and works great! Thanks again.