Could really use some help - AC

I could really use some help before light this thing on ******* fire and push it off a cliff...To start I've replaced the following:

Compressor - UAC CO4440C sanden style unit
Condensor - Went through 3 iterations before I found one that fit. Murray 7-4721
Accumulator/Drier - UAC-RD0049C
Both evaporators - Four Seasons 54599 and 54598
All lines minus the compressor octopus.

This was an absolute pain in the ass through and through as nothing wanted to go back together and the lines in the evaporators/condenser either had too much of a bend or were too short. Went through several iterations of condenser as well as front evaporator before it finally worked out. Finally got to the point where I can start the truck again and start charging (verified vacuum over the course of several days while I chased a few other odds and ends down). Cans 1-3 (120z cans, capacity is 3.5-4lbs depending on what chart or sticker you look at) went fairly smooth, however, can 4 it looks like I'm getting fairly high low side pressures and low high side pressures. The compressor itself said it was filled with 6.1oz of oil and I added approx 4oz to the drier with the intentions to add the remainder while charging. Air coming out of the vents is....cool, but not cold. Chart that I found says that the compressor is likely bad, hoping that's not the case, but if it is, then it is.

Just prior to shutting off - about half through can #4


Shut off, disconnected gauges and noticed shrader valves were leaking


Started back up again and finished off can #4

What refrigerant did you use? Real R134A or 'R134A Compatible" or R134A Replacement"?

Project Farm on Youtube just had a great video explaining these non-R134A cans that are on the market now. If you try to fill to normal 134A pressure's, it'll be over full.

What year, make, model , rear air also?

Reminds me of the issue I had with the Sanden compressor looking at the gauge readings. Went to a Four Seasons 10 cylinder 88947 and fixed my lack of cooling issue. The Sanden is 155cc displacement vs the 10 cylinders 210cc.

Bring the engine up to 2,000 rpm. I bet the pressures somewhat normalize when you do.

99 suburban w/6.5 and rear air.

RichLo said:

What refrigerant did you use? Real R134A or 'R134A Compatible" or R134A Replacement"?

Project Farm on Youtube just had a great video explaining these non-R134A cans that are on the market now. If you try to fill to normal 134A pressure's, it'll be over full.

Click to expand...

Can says R134, but it's from Wallyworld, so maybe a bait and switch? Also, definitely not resealable like it's supposed to be, learned that the hard way. Lol

L31MaxExpress said:

Reminds me of the issue I had with the Sanden compressor looking at the gauge readings. Went to a Four Seasons 10 cylinder 88947 and fixed my lack of cooling issue. The Sanden is 155cc displacement vs the 10 cylinders 210cc.

Bring the engine up to 2,000 rpm. I bet the pressures somewhat normalize when you do.

Click to expand...

Currently in a battle with RockAuto as just about every part I ordered through them for this has been faulty. Wouldn't be surprised if the compressor is also on that list

chevman_88 said:

99 suburban w/6.5 and rear air.



Can says R134, but it's from Wallyworld, so maybe a bait and switch? Also, definitely not resealable like it's supposed to be, learned that the hard way. Lol

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Click to expand...

Thats the right stuff, the new cans have that red 'Seal' on top, the fake cans have the old kind that you have to puncture

chevman_88 said:

Currently in a battle with RockAuto as just about every part I ordered through them for this has been faulty. Wouldn't be surprised if the compressor is also on that list

Click to expand...

Mine was a genuine 4261 Sanden shipped to me from the Wylie, TX Sanden location. 155cc is just not enough displacement to keep up with dual evaporator and marginal at best on a single evaporator. It was a fight to get that 4261 to cool even a single evaporator well. I had to add a GM severe duty fan clutch, a pusher condenser fan and play with a charge a good bit to get it to cool mid-low 40s at idle. I feel like the 88947 would still do a better job at lower engine rpm. The sanden struggles to pull the low side pressure down enough to get good cooling. @Wildblue19 had the same issue in his suburban. Has since gone from a GM S10 V7 compressor to dual V7s and dual condensers on it. His suburban has independent systems front and rear now to get adequate cooling capacity.

L31MaxExpress said:

Mine was a genuine 4261 Sanden shipped to me from the Wylie, TX Sanden location. 155cc is just not enough displacement to keep up with dual evaporator and marginal at best on a single evaporator. It was a fight to get that 4261 to cool even a single evaporator well. I had to add a GM severe duty fan clutch, a pusher condenser fan and play with a charge a good bit to get it to cool mid-low 40s at idle. I feel like the 88947 would still do a better job at lower engine rpm. The sanden struggles to pull the low side pressure down enough to get good cooling. @Wildblue19 had the same issue in his suburban. Has since gone from a GM S10 V7 compressor to dual V7s and dual condensers on it. His suburban has independent systems front and rear now to get adequate cooling capacity.

Click to expand...

Looking at the 88947, it says to use PAG 46. I've got 100 in now, guessing if I changed compressors it would be a flush and drier replacement?

chevman_88 said:

Looking at the 88947, it says to use PAG 46. I've got 100 in now, guessing if I changed compressors it would be a flush and drier replacement?

Click to expand...

Unfortunately that is how I did it. Mine had the Sanden oil in it. I flushed it out, replaced the accumulator and swapped to Pag 46. I am sure a small amount of Pag 100 hurts nothing though provided the bulk of the oil is the thinner 46 viscosity. When PAG first came out IIRC IT was all 150 and I felt they had lost their mind. Mineral oil was like 525.

I have used ICE 32 basically since it came out. It was available as a 2oz vile or a small 3 oz pressurized can with 2 oz of additive and 1 oz of R134a under the name CoolDown. I use PAG with the ICE 32 additive in it myself, seems to work well. Back when ICE32 only came in 2oz viles, I injected it into my 2006 Ram with an oil injector and saw a 5°F reduction in vent temps within minutes of it circulating in the system. The stuff works and I have used it ever since.