bought the truck from my father the a/c worked for the most part but the last few years he owned it the AC got weaker/warmer.
I had it charged with freon once and it was good for short time till it blew warm again after few months. After looking around found a small stone or something made a hole in my AC condenser (right on the tube). replaced AC condenser and dryer/accumulator and had it evac/recharged. Blows ICE cold now, but now i notice that around town it will blow ice cold all day long but if i go on the highway or interstate after 15-20 minutes it will start to blow warmer and warmer until its outside air temp. If i shut it off for 10 minutes then turn it back on it will blow ice cold again.
Again and again and again...
When it does this all the AC (compressor and such is still working), the blower motor (squirrel cage) still blows. the air temp coming out is just warm and kinda slows down a little.
A have read about and watched the heatertreater blend door fix and it seems to be what i am suffering from. any one else fix their AC issues with the heatertreater.
only other thing it could be is vacuum, everything thing like vacuum lines looks good and that would only cause an issue with air outlet location issues like "air only blows out defrost vent all the time"
$120 for the heatertreater door which i will do soon... and post back my results
For me it happens on both AC and max AC, the only difference between those two is the vacuum controlled outside fresh air (AC) and the recirculation (MAX AC) door. The vent outlet selector is also vacuum controlled and that works fine for me.
The blend door blends air between the heater core and the AC evaporator, but i read somewhere that in MAX AC the heater core has no coolant flowing through it, so i am thinking my blend door shifts toward the empty heater core and away from the AC evaporator causing my AC loss and outside feeling air.
On heater treater's website they say "blend door can shift/change during hard turns or bumps" and the door actuator/motor losses track of where it is, because the center plastic shaft of the plastic door is broken.
sounds like your evaporator is freezing up. This can happen if the compressor does not cycle. Check your pressure switche connectors to be sure they weren't bypassed during charging, and then not reconnected to the switches.
what sounds like is happening is the evap is freezing up and thats y it starts blowing cold and then it gets warmer cuz the evap is frozen and so no air is getting through then the it starts getting warmer then eventually the evap thaws and gets cold again.
Check your low side pressure with the ac on max, your are looking for about 30psi. The cycling switch will operate the compressor from 21 and cut it off around 42.
If you are seeing numbers over that then the switch is shot, if its under then you might need a charge. You can change the switch with out evacuating the system or at least my 99 ford manual says you can.
I have a low pressure only gauge and a EZ charge can.
My compressor is running all the time, it does not cycle off ever. right now
I think i checked that a few weeks ago, when i was comparing my AC pressures to my wifes car. I think the low pressure stayed right at 30-32 psi and did not move. Any reason for this, i can recheck to verify pressure. Clogged orifice tube filter thingy? I have never replaced that, but i have one (motorcraft) i didn't replace it before because i didn't know where it was located...