AC overhaul - Compressor upgrade? Condensor?

[L31MaxExpress]

Great stuff L31ME!

I had a little time yesterday and today to work on the AC. I had my neighbor with the machine pull the refrigerant yesterday. He recovered roughly 64 oz which is spec for this suburban, so that was good. I still replaced the high pressure valve.

1) I slapped on the four seasons compressor 88947 with the smaller pulley. Luckily happened to have a slightly shorter belt that fit perfect. The compressor case looks same size as the Delphi I pulled. But it is larger 210cc capacity?

2) I swapped in the Boxi parallel flow condenser (Part number in my last post) It was a good stock fit.

3) I swapped in a fixed 0.062 orifice tube.
The one it replaced was preinstalled in the new UAC refrigerant y-line I installed with winter overhaul. It appeared to be slightly smaller orifice than the 0.062" fixed that is now installed.

Pulled a vacuum for over an hour to draw out any moisture. Held vacuum perfectly for over an hour. Looking to recharge tomorrow. Just need to decide on putting r134 back in or giving the r152 a shot. I will probably just have r134 put in for now just to limit the variables. I should have case of r152a, side canister tap arriving in next day or two. So if the system is still not up to *****, I will consider trying r152a.

I haven't installed the pusher fan. Looks like I will have to relocate the trans cooler or the engine oil cooler to make the aux fan fit. That will have to wait until winter.

I do have that adjustable low side cutout switch on hand (and connector), and have not installed that yet. What's a good way to determine what pressure current stock switch is cutting out at? Same question for high side cutoff switch? Is there a test with gauges or?

Lastly, the

For low pressure cutout, turn the rear blower off if equipped, front blower on low speed, recirculate function on, rev the engine up to 2,000 rpm it should cycle on the low pressure cutout around 22 psi. For high side cutout, both fans on high speed, outside air, block the grille off with cardboard, then bring it up to 2K, should see it cut before 430 psi. That test is a bit scary with old rubber hoses especially, definitely wear some safety goggles as PPE.

88947 is advertised as a 10 cylinder, 210cc displacement. Works better than any compressor I have had on my 97 including the factory OE GM. From what I can find the OE 6 cylinder HT6 was 170cc.

 

[BowhunterBrown]

Thanks L31ME, you are the coolest!


I didn't see any mention of the 210cc capacity in the product info, so I was a little unsure. I look forward to trying it out today.

Did you see I edited my comment I think after you replied to include mention of the late model Tahoe condenser with subcooler?

 

[L31MaxExpress]

Thanks L31ME, you are the coolest!


I didn't see any mention of the 210cc capacity in the product info, so I was a little unsure. I look forward to trying it out today.

Did you see I edited my comment I think after you replied to include mention of the late model Tahoe condenser with subcooler?

I missed your edited reply. Sucks that it is a little too big and the fittings are off. That is the hard part about at looking at printed specifications. It was a suggestion as to what might fit not a certainty. I am sure it would cool incrediy well. Maybe if enough of us bugged Denso they would build one for our trucks doubt it but might be worth a try.

 

[BowhunterBrown]

I missed your edited reply. Sucks that it is a little too big and the fittings are off. That is the hard part about at looking at printed specifications. It was a suggestion as to what might fit not a certainty. I am sure it would cool incrediy well. Maybe if enough of us bugged Denso they would build one for our trucks doubt it but might be worth a try.

I don't hold against you for recommending it. I knew it might require modification. I am debating returning it or not, might try to make it work next go around considering I am still not getting good ac performance after recharging this morning.

At the moment, I think I might have air in system. I had it vacuumed down last night and holding 30 inches of vacuum over night. Took it to neighbors and he hooked up his machine. I asked him if he had to purge the lines of air and he said no the machine does it.

Anyway, his machine pumped in 3.5 lbs. Or 56 ounces, but it didnt want to push anymore in. 64 oz is spec. This afternoon I hooked up my gauges and added 12 oz can. (This is all r134 BTW, my shipment of electronic duster cans was delayed, so no r152 to try, yet)

When I went to add the 12 oz this afternoon I was surprised when I went to purge the high and low pressure lines from manifold set I got nothing but what appeared to be air. I hooked both low and high side gauge connections to ports and opened each. Then depressed purge valve in center of gauges expecting to get some air followed by some "stuff" but nothing but air for several seconds. Shrugged my shoulders and added the 12 oz can.

Shouldn't I see some sign of refrigerant coming out when purging the lines, much like you do when purging the line from can to gauges?
The vehicle hadn't been driven for several hours and Ambient is upper 80s. I would think some sputtering of liquid refrigerant would be expelled from purge valve after just a second.

Anyway, temperature at vents is not real impressive. My lowside pressure seems a touch high. It's about 87 degrees and 40% humidity for these numbers.

First picture is idle. Second is at 1800-2000 rpm .

Should be roughly 66 oz of r134 in system calling for 64 oz.

 

[BowhunterBrown]

Also, static pressure is reading about 10-12 degrees high for this 86 degree Ambient temp.

 

[chevman_88]

It looks like you're getting the same pressures I am. Still running the Sanden or did you swap to the HT6 already?

Edit: my OE drier says 3.5# R134a but a lot of tables show a full 4# curious as to if you still had your OE drier and what the sticker showed.

 

[BowhunterBrown]

I don't have the oe drier. I replaced it this winter when I replaced everything.

I have seen 64 oz (4 lbs) and all the way down to 48 oz (3 lbs) listed online for these suburbans so I have been relying on gauges.

I bled off a little "air" and seems to be cooling better, but hard to say if it's from letting some off or because this time I had a box fan in front of condenser while assistant held rpm at 1800.
The good news is I was able to watch lowside gauge go down to 27psi and low side pressure switch never cut the clutch so that's good. And we saw 45 degrees at front duct so nearly 40 under Ambient. Need to test thermometers yet. Not sure I trust their readings. So if it was because the box fan, then I definitely will need to work on getting my auxiliary fan mounted. For now it's hard to say. Tomorrow will do some driving.
That's at 1800 rpm
86 F, 40% humidity
Mediocore Box fan on condenser.

 

[BowhunterBrown]

For low pressure cutout, turn the rear blower off if equipped, front blower on low speed, recirculate function on, rev the engine up to 2,000 rpm it should cycle on the low pressure cutout around 22 psi. For high side cutout, both fans on high speed, outside air, block the grille off with cardboard, then bring it up to 2K, should see it cut before 430 psi. That test is a bit scary with old rubber hoses especially, definitely wear some safety goggles as PPE.

88947 is advertised as a 10 cylinder, 210cc displacement. Works better than any compressor I have had on my 97 including the factory OE GM. From what I can find the OE 6 cylinder HT6 was 170cc.

I have the four seasons small pulley compressor 88947 on, which I believe is an ht6, not sure.

 

[BowhunterBrown]

Update, we haven't had any Temps over 90 lately so I haven't been able to put the system to the test. Still not 100 percent satisfied with Temps. I think the auxiliary fan will help a lot, but I need to relocate either trans cooler or oil cooler to underneath inside the frame rails with a temp switched fan, and that is a project I probably won't have time or funds for this summer.

I think I might have air in system. I had pulled a good vacuum for over over an hour and it held overnight, but just before having my neighbor refill the system I realized I failed to stand compressor on pulley for a few minutes to coat seal with oil per manufacturer instructions. So I pulled compressor stood it up on pulley and reinstalled, but was short on time to get over to my neighbors AC machine, so the final vacuum I pulled for maybe only 20 minutes. In hindsight, not sure that was enough to evacuate all air and moisture from a suburban with front and rear evaps.
That and his vacuum pump on his machine is not working, which makes me think air in the hook up lines is introduced to system on the refill, but I am not sure if that's the case.

Anyway, I hear hissing/gurgling in system after shutting down which makes me wonder if I am undercharged or have air in system, or both.

Additionally my static pressures are a touch high based on charts I have seen, which according to my reading, indicates possible air in system.

I don't have time this week but I am considering another evacuation and refill. I will debate over running the r152 in the meantime, as the cans of electrinic duster and can side puncture tool showed up in the mail.

I might also install the adjustable lowside compressor switch in the meantime. In driving around, the air dies get not as cold at times, making me think the compressor might be cycling off a little soon.

I also noticed that I am not seeing any water on the ground in the parking lot under the evap, hvac box drains, front or rear after a drive around time. Maybe under charged? Maybe cycling off too soon?

On another note, the condesor I installed does have a high side port on the condensor line. It's unused now, so I am thinking it might be a great place to add a pressure switch for the auxiliary fan. I found this one online but unsure if it would be a good choice. 240 a good tripping point?

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[bgroszewicz]

Good morning everyone, I am new with the chevys, I got a 1995 GMC C3500 SLE, that I am working on, I ve got a AC leak, and traced to be a compressor oil leak, decided to buy a 4 seasons kit with new compressor and drier. any advise on replacing that?
Any help is appreciated. Attached is the truck that i want to drop and will see how it comes...would like also some advise on dropping kits (would rather not doing the C notch just dropping like 3/5.

Thank you