1996 C1500 Reg Cab AC not working - what all do I need?

[Schurkey]

If it works "long term", you've succeeded.

I have a concern about how long you "vacuumed" the system. Overnight is good, but probably longer than absolutely needed. "Several hours" is what I hear recommended...but if you've worked on the thing all day, who wants to come back at ten at night and charge the system? I just let it go 'til morning. It's not like you can over-vacuum.

Vacuuming does three things:
1. Removes air. Air is not refrigerant. Air doesn't "cool".
2. Removes moisture. Water boils at ~70 degrees when under heavy vacuum. But it takes time--the vacuum has to hold long enough to boil all the water, and then suck out the water vapor. Ideally, there's not much water in the system to begin with. And the desiccant pouch will absorb some water. But "best practice" is to vacuum-out as much water as practical before adding refrigerant.
3. If the system holds vacuum for a reasonable length of time, it's passed a leak-test. It's not the best possible leak-test, but it's better than nothing.

 

[Erik the Awful]

any special trick to get freon out of the can?

Warm the can. When I'm charging, I put the can in a place where it's warm, but not too hot to hold my hand. Make sure the hose isn't going to get melted or chopped by the fan, and sit it with the hose at the top so you're not slugging your compressor with liquid.

 

[AuroraGirl]

Thanks to all for this help!! Clearly I was in a little over my head here, though that is kinda how i force myself to learn new things sometimes. Not exactly a textbook perfect install procedure (my fault of course), but thankfully I think things worked out well.

I got a new can tap from oreillys which then required a 1/2" ACME to 1/4 flare adapter, luckily i had this.

vacuumed out the system and started from scratch with new tap, worked great. used a scale to measure can so i know i got just the right amount of refrigerant in there.

after about 20oz the compressor no longer cycled on-off intermittently and stayed on which is great.

i dont have a dial thermometer but it is blowing cold af.

if you have the same situation where youre doing this, using a fan to push airr at the front of the truck while idling to fill is a good idea. you seem done now but just helpful tip

 

[1998_K1500_Sub]

Warm the can. When I'm charging, I put the can in a place where it's warm, but not too hot to hold my hand. Make sure the hose isn't going to get melted or chopped by the fan, and sit it with the hose at the top so you're not slugging your compressor with liquid.

Ditto. I put the can in a small pail filled with hot water... that's if I want vapor. If I want liquid, heat's not necessary.

 

[someotherguy]

if you have the same situation where youre doing this, using a fan to push airr at the front of the truck while idling to fill is a good idea. you seem done now but just helpful tip

In super humid and hot Texas, this can be necessary. Done it.

Richard

 

[Stringer]

well looks like another mistake i have made on this truck. ac is barely blowing cold now. the refrigerant lines are extremely sweaty. attached manifold gauges and high pressure goes up to 425 b4 it drops down to 150 and shoots back up. low side gets down to 45 abd then shoots to 130

i tried adding refrigerant but the can immediately got super hot so i shut everything down.

 

[Schurkey]

I expect the pressures are changing due to the compressor cycling.

The can got hot because you were probably trying to add to the high side instead of the low side; or the low side when the compressor wasn't running.

HOW MUCH REFRIGERANT DID YOU ADD?

 

[Stringer]

I expect the pressures are changing due to the compressor cycling.

The can got hot because you were probably trying to add to the high side instead of the low side; or the low side when the compressor wasn't running.

HOW MUCH REFRIGERANT DID YOU ADD?

i probably did do that, tried adding to high side and not low

i didnt end up adding refrigerant. instead when i tried to get the high side manifold fitting off the truck, it kind of got stuck and started spraying everywhere so i lost some.

i suspect i may have let air in system during initial charging but not sure.