AC Not Getting Cold

[josh454]

Hi all,

Having issues getting cold air on my 86 Squarebody truck. Hoping someone with more knowledge assist.

So far I have replaced:
Compressor with a Sanden SD7H15 Compressor
Replaced the condenser with an aftermarket OE replacement
Replaced the Evaporator with an aftermarket OE replacement
Replaced the accumulator with Genuine GM part
Replaced the Orifice tube with the white ACDelco replacement (Twice, first time I put it in backwards)
According to my 86 GM repair manual it should take 56oz of R12. I initially charged 36 and could tell it wasn't cold so I went to 48oz with little change to the vent temps. (Didn't measure it but felt extremely similar)

85 Degree day with 45% humidity I'm getting 68 Degrees out of the center vent on Max AC with recirc on. Feels cool but not cold at all - driving down the road doesn't feel like it changes much, maybe a little bit.

Pressures with 48 oz and 85 ambient temps:
Static pressure is 109 on both sides. (Compared to my 2008 Suburban it was 105)
800 RPMs I'm getting 155/30
1500 RPOMs I'm getting 180/25
Low side kicks off about 23 PSI

Measuring the evaporator at one of the tubes I'm getting 47 degrees. I'm getting pretty close to 32 degrees on the tubes before and after the evaporator. High side line going into the condenser I'm getting 118 and after I'm getting 92. I have dual SPAL 14" fans running on high with an aftermarket Cold Case heavy duty radiator.

I noticed the accumulator starts to freeze about 26 PSI and back to about 4" in front of the compressor.

One of the things I'm confused about is how the Evaporator line can be ice cold but the tubes in the actual evaporator are only 47 degrees. Totally confused at this point wondering if maybe the output of the Sanden SD7H15 doesn't match the orifice tube size? Any other ideas? Appreciate the help, at my wits end on this one!

Thanks,
Josh

 

[fast 99]

How about the heater door not in the correct position, broken or leaking? Try pinching off one heater hose see if there is improvement. Although high side pressures aren't excessively high does the clutch fan work?

 

[YakkoWarner]

I'd second the idea of checking the heater door. If you're freezing up on the evap line but barely anything cool coming out the vents it sounds like you're trying to cool down heated air. Super easy way to test this theory: Turn on the A/C as soon as you start the truck (before the coolant has a chance to get hot). Do you get good cool air that slowly gets warmer as the engine warms up?

I was planning on bypassing my heater core for the summer, but since the rest of my system seems to be struggling now, I'm going to leave it be for now until I can spring for at least a new crossflow condensor, orifice tube and accummulator/dryer.