AC works for about 30 minutes and then starts to fade(blow warmer) on Jd 3720

[rdbigfarmboy]

Im going with overfilled freon. When all the parts heat up the expansion doesnt allow the referigerant to pass. T1P1V1=T2P2V2
That thing has a lot of stuff all warming up the condensor evaporator assembly.

When it was being initially charged it gets super cooler quicker if you put more than specified. Like say 2.5# instead of 2.2#. As long as you dont work the tractor it will stay cool. Like for cruising

 

[brin]

My Jeep had the same problem...cold AC at first and then warm....just took it into the dealer this AM ...the AC condenser is clogged with fescue seed from me driving through the pasture before we cut and baled the hay...live and learn....Check your AC condenser...it could be full of debris you are not seeing and it needs to be blown out from behind the condenser....so I have found out....