My vent temps are a mixed bag. I've had this truck 6 years, bought it from the original owner who babied it and literally 'soccer mom'd' it between Palm Springs and San Diego exclusively. She was very happy with the A/C. Since I've owned it in Phoenix, it's not too bad on the highway (especially starting from a shaded garage) at about 50F vent temps. I do have to turn it down on freeway trips. Now in town and even worse, on the trail, it's horrible. Slow moving is about 75F vent temps. Before the 150A alternator that puts out 13.7-14.4v and all the amperage at idle, I was running the blower and 100 series aux fan at 10.7-11.4v sitting/sweating in traffic and the air was quite humid. I did the blue fan clutch mod with 23K fluid and tuned it to 100F (if I recall correctly, maybe less) per
@landtank's instructions. Even with the crap alternator performance, the engine was quite happy but the A/C was marginally better at about 65F-70F. Prior to taking into CBT for an evac/charge last July because I found a leaking Schrader valve thinking it was causing a low charge condition, I cleaned the condenser and evaporator and installed the 100 series fan. They charged it, it was 45F in their 75F shop and they called it good. Same performance this year as last. The wife's RX100 literally blows mine away, it's 4 years newer and 1000% better. Idling in traffic is a solid 45F and the freeway is sub-40F's. I know that her parallel flow condenser is the only real difference and am putting one in mine.
This morning I drove from a shaded garage, in 100F ambient, and it was 49F all the way. After parking for 1 hour, the vent was 100.6 (ambient was 101), I started it and it idled down to 69.5. I revved to 1500RPM and locked the hand throttle and waited about 5 min for it to get to 54.1. This was all with the doors CLOSED, on Max at the Center vent. I drove down the freeway, ambient was 101 still, and it returned to 49F. It never gets better than that.
I suspect the condenser is to blame for some of it but I suspect there's a drier, TXV, too much oil, etc. issue that is giving me grief. I'll be base-lining it by removing/cleaning the evap, replacing the drier and TXV, and recharging the system. The only NEW addition will the a true parallel flow condenser. I suspect I'll still need an aux fan and have a 12" 24v SPAL sitting in the garage I'm planning on cramming in there and running at 12v and compare it to the 100 series fan. I'm betting my highway temps will be 40F and I'm hoping my low speed/sitting temps will be close. The fan should push it over the edge.