A/C blows cool despite new o-rings, freon recharge

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May 30, 2015
SW Montana
Greetings from pre-monsoon New Mexico, where today it's pushing 90 degrees and a redlining at an 11 on the UV index... and where the recently maintained A/C in my '97 FZJ80 is still blowing "cool" rather than cold. I've done a good bit of searching / reading here in the forum, but admit to being a n00b with auto mechanics, especially the finer points of the HVAC systems.

So my truck has the Auto setting, and if the ambient temperature of the truck is "garage temperature" as opposed to having sat out in the hot sun, the a/c feels like it wants to crank out frigid air, but never quite gets there. If the truck has a high ambient temperature, turning the a/c on makes it blow warm. I had thought that part of the problem might be that I just need to be patient and let the system cool itself down, but even after a couple of minutes running on the fans on high at 65 degrees on the slider, no noticeable change in temperature.

So - in the last 3 weeks, my truck has had a couple of new o-rings changed in, and a freon recharge. I checked the throw of the mix valve cable this morning, and that checks out. All I can think now is leak somewhere?

Anybody have any bright ideas? Bueller?

Thanks in advance.
How old is the compressor? What is the high side pressure of the compressor? Had an issue with a '95 that was due to a defective expansion valve. With the bad valve it would stick every so often, wouldn't blow cold or overpressure the system and blow an o-ring. (Truck had a new compressor, evaporator, expansion valve, dryer, and o-rings... A mechanic diagnosed it as a bad expansion valve, replaced/recharged and it works like a champ.)

Of course the simple things, check your A/C evaporator for blockage/corrosion.
Over filling and under filling will cause reduced cooling capacity. How much refrigerant was put in system?

What are your high side and low-side pressures?

The Accumulator/Drier can have an effect.

Do you have a 40 degrees drop over outside temperature.

Have you tried lightly spraying condenser with water hose to rule it out.
How does driving 55 mph down the road affect the vent temps? I'm wondering if your fan clutch is going limp .
Thanks for the feedback, everyone.

My truck is running a Dodge/Cummins compressor (new), and everything else is Toyota OEM. The fan clutch has recently been replaced, as have the high side hose and schrader valves. I've just come out of a long swap where many things have been replaced, so I've got some homework to do. I'm learning system by system how these trucks work so it's a bit of a learning curve for me, but it's satisfying.

I'll check the accumulator, evaporator and the fluid levels.
MEASURE the high side/low side pressure while the compressor is active.


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