AC overhaul - Compressor upgrade? Condensor?

1998 Suburban K2500 6.5 td

I replaced every single part of the AC system this winter (except manifold lines on top of compressor - part unavailable).

New parts:
Delphi Ht6 compressor
Front and rear evap cores
Denson condensor (~15"x30"x1.25")
Ac Delco drier
New rear lines, (ac auto solutions off ebay -rubber lines).
New head unit, aka climate control module
Expansion valve and orifice tube.
Rebuilt havac boxes, New heater cores, fixed actuators, new blend door flappers.

Original Goal was to have ice cold AC by Summer. Right now it's 100 daytime high and AC performance is underwhelming.

Long story short, I have on order a few different larger condensers (other gmt400 c/k suburban applications), a couple different orifice tube, thermometer for vent testing, high pressure valve, low pressure schrader valve, etc., but I can't determine which upgraded four seasons 210cc compressor to go with...

1) Stock pulley size or Undersize, van application?

I AM GOING ALL IN. I want cold AC. I am ordering all the parts and preparing to have ducks in a row for ANOTHER* evacuation and refill (luckily my neighbor has a Profesional machine (robinair?) And diesnt charge much). Just learned from other recent ac threads of the larger displacement compressors.

Next on the list Compressor.

*I did the double up on orifice tube thing. Didn't pull the one out of the new condensor before installing, so that required a suck down/ refill to remedy.

2) going to have multiple condensers on hand for this next go around of cracked open systems work. Have a larger 35x18"x1.5" on the way, (OSC 4544?).
It just seams obvious that a suburban with front and rear AC should have a larger compressor and condensor, any reason why they would not have?

The van compressor itself is the same, just the clutch pulley is smaller so it spins more quickly. I do not understand the logic of the larger pulley in a dual evaporator system myself. Seems like GM should have used the larger diameter clutch on a single evaporator system and the smaller one on a dual evaporator system regardless.

Install the condenser pusher fan and 11 bladed fan if you do not have one already. The GM 154672 clutch is working well for me too.

What are your pressures currently reading at idle and at 2,000 rpm with both blowers on high speed.

L31MaxExpress said:

The van compressor itself is the same, just the clutch pulley is smaller so it spins more quickly. I do not understand the logic of the larger pulley in a dual evaporator system myself. Seems like GM should have used the larger diameter clutch on a single evaporator system and the smaller one on a dual evaporator system regardless.

Install the condenser pusher fan and 11 bladed fan if you do not have one already. The GM 154672 clutch is working well for me too.

What are your pressures currently reading at idle and at 2,000 rpm with both blowers on high speed.

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This was at Idle with ac max (manual controls) fans on high. I dont have 2,000 rpm reading at the moment. I know, the cheap harbor freight gauges aren't the best. This was after adding 12oz after replacing low side scrader valve (found to leak after second evacuation, refill). Used nifty tool to replace without having to evacuate system again.

I have a relatively new Hayden fan clutch. It's for a duramax application. A lot of 6.5 guys run them as an upgrade. I recently tweaked the bimetal spring and it seems to come on a touch sooner now.
I do have the electric fan coming in recent parts order. Any suggestions on wiring that in would be appreciated.

I think I will pull the trigger on the small pulley 210cc four seasons p/n 88947
I see they require pag46, so looks like I will be flushing all the parts of 150 if I swap a 210cc compressor in.

There's nothing wrong with cheap gauges if they work.

Yes, you can replace the clutch without opening the system. It's been decades since I replaced an A/C clutch, but I remember it needing a special tool and still being a pain in the butt.

Erik the Awful said:

Yes, you can replace the clutch without opening the system.

Click to expand...

Click to expand...

Sorry, I edited my comment. I thought lm1maxExpress was referencing compressor clutch part number, then realized he was taking about fan clutch.

Good to know anyway.

Make sure your high pressure switch is the correct rating. I had that problem today actually. The replacement switch i installed years ago is designed to cut the compressor off at around 275-280 psi. My service manual states the high pressure switch kills the compressor around 410-450 psi. So i will be ordering a new pressure switch accordingly and that should solve my compressor cycling with off-idle low speed driving.

JohnZ71 said:

Make sure your high pressure switch is the correct rating. I had that problem today actually. The replacement switch i installed years ago is designed to cut the compressor off at around 275-280 psi. My service manual states the high pressure switch kills the compressor around 410-450 psi. So i will be ordering a new pressure switch accordingly and that should solve my compressor cycling with off-idle low speed driving.

Click to expand...

I had that issue as well. Many manufacturers have started selling the 275-280 psi switch in place of the 430 psi unit.

BowhunterBrown said:

This was at Idle with ac max (manual controls) fans on high. I dont have 2,000 rpm reading at the moment. I know, the cheap harbor freight gauges aren't the best. This was after adding 12oz after replacing low side scrader valve (found to leak after second evacuation, refill). Used nifty tool to replace without having to evacuate system again.

I have a relatively new Hayden fan clutch. It's for a duramax application. A lot of 6.5 guys run them as an upgrade. I recently tweaked the bimetal spring and it seems to come on a touch sooner now.
I do have the electric fan coming in recent parts order. Any suggestions on wiring that in would be appreciated.

I think I will pull the trigger on the small pulley 210cc four seasons p/n 88947
I see they require pag46, so looks like I will be flushing all the parts of 150 if I swap a 210cc compressor in.

Click to expand...

Ah 6.5L, I missed that detain. Seen a few Duramax fan blade swaps on those too.

It is definitely having a hard time pulling down the low side pressure. You said that was in 100F? The high side pressure seems low for that ambient temp.

For wiring, I have made my own a few times and also used Painless 30101 kit. To activate the relay, I tend to tie into the orange high blower relay turn on signal although others tie into the green wire on the ac clutch.

L31MaxExpress said:

It is definitely having a hard time pulling down the low side pressure. You said that was in 100F? The high side pressure seems low for that ambient temp.

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That was 80 degrees. We are currently experiencing some 100 degree days here, but that was most recent gauge reading from a week ago at 80 degrees.

L31MaxExpress said:

For wiring, I have made my own a few times and also used Painless 30101 kit. To activate the relay, I tend to tie into the orange high blower relay turn on signal although others tie into the green wire on the ac clutch.

Click to expand...

Makes sense. I was thinking of tying into compressor clutch lead, just wasnt sure if that was a bad idea or not. A little gunshy after popping that newer AC delco head unit/control module.

JohnZ71 said:

Make sure your high pressure switch is the correct rating. I had that problem today actually. The replacement switch i installed years ago is designed to cut the compressor off at around 275-280 psi. My service manual states the high pressure switch kills the compressor around 410-450 psi. So i will be ordering a new pressure switch accordingly and that should solve my compressor cycling with off-idle low speed driving.

Click to expand...

I still have original high pressure switch on the rig. I guess I failed to mention that I did not replace high or low pressure switches when I replaced everything. Maybe that was good thing I did not replace that. Mine does not seem to cycleoff while cruisng. I do get pretty cold out of the rear vents and decent cold air out of the front, but I just want to get this thing working better than stock. I need to be able to cool the hot suburban cab off fast. I think the larger compressor with smaller clutch pulley is going to help as well as swapping for larger cpacity condensor. It is lame that the suburbans these years (1998) got the same compressor and condensor as a same year truck with no rear AC.

BowhunterBrown said:

That was 80 degrees. We are currently experiencing some 100 degree days here, but that was most recent gauge reading from a week ago at 80 degrees.



Makes sense. I was thinking of tying into compressor clutch lead, just wasnt sure if that was a bad idea or not. A little gunshy after popping that newer AC delco head unit/control module.



I still have original high pressure switch on the rig. I guess I failed to mention that I did not replace high or low pressure switches when I replaced everything. Maybe that was good thing I did not replace that. Mine does not seem to cycleoff while cruisng. I do get pretty cold out of the rear vents and decent cold air out of the front, but I just want to get this thing working better than stock. I need to be able to cool the hot suburban cab off fast. I think the larger compressor with smaller clutch pulley is going to help as well as swapping for larger cpacity condensor. It is lame that the suburbans these years (1998) got the same compressor and condensor as a same year truck with no rear AC.

Click to expand...

My 99 Tahoe was handicapped with the same junk setup. Atleast it had the good condenser and condenser fan and being a little less cavernous on the interior than a suburban, worked quite well. The 97 van is what struggled at idle and lower speeds. GM had the nearly worthless 5 bladed steel fan on it as built. One of GMs great penny pinching moves I am sure. The vans should have all had the pusher fan and atleast the 11 bladed fan, they tend to run hot.

As compact as the early 90s G-Vans are between the grille and condenser GM still sandwiched a factort pusher fan in some of them.