What to do with my old A/C thread #10425

[someotherguy]

Truck in question is the '93 C3500 regular cab dually 7.4 / NV4500, last year for R12 systems in these trucks.

Bought it with non-working A/C, the electrical connector to the compressor clutch is broken off. Considering a new clutch is $100 and I'd still have this beat-up old 160K+ mile compressor that may not be any good after all.. and a NEW compressor kit w/dryer etc. is about $200 depending on brand, or $300 with condenser included........seems dumb for me to replace the clutch.

Moving on -

1. Just replace the compressor, dryer, orifice tube.. or do the condenser as well? Kit comes with all the o-rings for the entire system, but I'm leery of pulling apart connections that may be seized. I do know I'll be pulling several things loose anyway to flush out the system with solvent before putting the new parts on, though. Leaning towards the GPD 9611682 kit with the upgraded scroll design compressor.

2. Kit comes with "black" orifice tube. I'm in Houston where it's stupid hot and humid in the summer, I mean we're roasting down here. I've seen others mention the "red" tube. What should I get?

3. Converting to R134a seems like I have no other option but this, or to hunt pricey R12. Thoughts? Considering GPD 1311423 retrofit kit.

Richard

 

[L31MaxExpress]

Truck in question is the '93 C3500 regular cab dually 7.4 / NV4500, last year for R12 systems in these trucks.

Bought it with non-working A/C, the electrical connector to the compressor clutch is broken off. Considering a new clutch is $100 and I'd still have this beat-up old 160K+ mile compressor that may not be any good after all.. and a NEW compressor kit w/dryer etc. is about $200 depending on brand, or $300 with condenser included........seems dumb for me to replace the clutch.

Moving on -

1. Just replace the compressor, dryer, orifice tube.. or do the condenser as well? Kit comes with all the o-rings for the entire system, but I'm leery of pulling apart connections that may be seized. I do know I'll be pulling several things loose anyway to flush out the system with solvent before putting the new parts on, though. Leaning towards the GPD 9611682 kit with the upgraded scroll design compressor.

2. Kit comes with "black" orifice tube. I'm in Houston where it's stupid hot and humid in the summer, I mean we're roasting down here. I've seen others mention the "red" tube. What should I get?

3. Converting to R134a seems like I have no other option but this, or to hunt pricey R12. Thoughts? Considering GPD 1311423 retrofit kit.

Richard

We are roasting up here in Fort Worth area too.

Convert to R134a or R152a, same oil either way.

I would change the condenser, get a modern microtube parallel flow. My pressures dropped noticeably (like 50 psi) after installing one in the van in place of the OEM serpentine flow unit.

Where is the orifice tube mounted on that year? If it is in the condenser, a Yellow tube for a 1994ish Cadillac Seville or Eldarado has the same 0.062" orifice as the Ford Red Tube.

Get a later Vortec era 11 bladed fan and put it on while you are there. It bolts to the TBI clutch, a little bit of a pain to bolt the clutch back on with all the blades, but worth the trouble. It moves more air than the fat 5 bladed fan GM put on the 454s, 8.1Ls and interestingly 4.3 CPI Astros. Make sure the clutch is fresh as well and it is the proper one for an AC truck. GM also used 2 different clutches depending on the axle ratio. The taller geared trucks use a stiffer clutch. Both are fairly equal at full coupling, but the taller geared runs a higher percentage of coupling when it is in freewheel mode to make up for the lower engine rpm.

The scroll compressors are very smooth, do not take much power to run, but they do not cool quite as well at idle as a R4 or Sanden SD7H15 though. I would get conversion brackets and go to a Sanden myself.

I had a scroll on a R4 high mount bracket on the 6.0L in the 1987 G20. It would get down into the 30s on the highway, but only cooled about 55°F at idle. Stock 87 AC system save for the scroll, Red tube and R152a. It is getting a Valeo HT6 replacement with the L31. I run an 11-bladed F150 5.4 3-valve fan on that van as it is a little smaller than the GM counterpart and fits the OEM shroud without rubbing it. Cooling that dark royal blue roofed van in the Texas sun is a challenge though as it only has front dash ac and I probably need to yank the evaporator core to inspect, clean it out and reseal everything.

 

[someotherguy]

We are roasting up here in Fort Worth area too.

Convert to R134a or R152a, same oil either way.

I would change the condenser, get a modern microtube parallel flow. My pressures dropped noticeably (like 50 psi) after installing one in the van in place of the OEM serpentine flow unit.

Where is the orifice tube mounted on that year? If it is in the condenser, a Yellow tube for a 1994ish Cadillac Seville or Eldarado has the same 0.062" orifice as the Ford Red Tube.

Get a later Vortec era 11 bladed fan and put it on while you are there. It bolts to the TBI clutch, a little bit of a pain to bolt the clutch back on with all the blades, but worth the trouble. It moves more air than the fat 5 bladed fan GM put on the 454s, 8.1Ls and interestingly 4.3 CPI Astros. Make sure the clutch is fresh as well and it is the proper one for an AC truck. GM also used 2 different clutches depending on the axle ratio. The taller geared trucks use a stiffer clutch. Both are fairly equal at full coupling, but the taller geared runs a higher percentage of coupling when it is in freewheel mode to make up for the lower engine rpm.

The scroll compressors are very smooth, do not take much power to run, but they do not cool quite as well at idle as a R4 or Sanden SD7H15 though. I would get conversion brackets and go to a Sanden myself.

I had a scroll on a R4 high mount bracket on the 6.0L in the 1987 G20. It would get down into the 30s on the highway, but only cooled about 55°F at idle. Stock 87 AC system save for the scroll, Red tube and R152a. It is getting a Valeo HT6 replacement with the L31. I run an 11-bladed F150 5.4 3-valve fan on that van as it is a little smaller than the GM counterpart and fits the OEM shroud without rubbing it. Cooling that dark royal blue roofed van in the Texas sun is a challenge though as it only has front dash ac.

Ugh, didn't know that about the scroll compressors. However we're talking about a single cab truck vs. your van - would you still advise against it? Amount of cab space to cool is much smaller, but I still don't want to be bothered by warm vent temps while stuck in traffic.

I've looked into the Sanden conversions but I don't see brackets that say specifically they fit the TBI big block, only the small block.

Oh and yeah, orifice is in the condenser, that change happened back in '91 IIRC. I don't know much about converting to the parallel flow condensers other than I just recently read some claim that you can't flush them. Any thoughts on that?

Richard

 

[L31MaxExpress]

Ugh, didn't know that about the scroll compressors. However we're talking about a single cab truck vs. your van - would you still advise against it? Amount of cab space to cool is much smaller, but I still don't want to be bothered by warm vent temps while stuck in traffic.

I've looked into the Sanden conversions but I don't see brackets that say specifically they fit the TBI big block, only the small block.

Oh and yeah, orifice is in the condenser, that change happened back in '91 IIRC. I don't know much about converting to the parallel flow condensers other than I just recently read some claim that you can't flush them. Any thoughts on that?

Richard

I do not know why those simple conversion brackets and misc hardware like bolts and washers would not space it correctly. So far I have put the GM rear head style Sanden on about 6 different vehicles. The clutch does look a bit goofy with an 8-rib pulley and a 6 groove belt, but the belt rides on it perfectly and it offers add flexability in the spacing. I have used those brackets on a 2.8L Blazer, 4.3L S10, 4.3L Astro, and a TPI F-Car and a late 80s Jaguar (yes those came with R4s too).

It might cool acceptably in a single cab truck, your interior volume is about 1/5 of the van.

Before I pulled the 6.0L I was considering adding a small low mount ICT bracket and matching baby Sanden to add rear air. Then again the thing mainly sits when it is over 90°F because it is a day adventure/overnight camping setup. Only time I use in the heat is if I need to go to Home Depot or Lowes to pickup stuff that will not fit in the bed of a short bed truck. 4x8 drywall, counter tops, fence poles, stuff like that. Around town the ac was good enough to take the edge off even in traffic, but I had some sweat on my face until it was moving a constant 50+ mph with the Scroll and that was with a TH400/3.08 gear and no overdrive. Engine had to get up to about 1,500-2,000 rpm before it got nice and cold and at 2,500 rpm @ 70ish I could have hung meat off the dash.

 

[Scooterwrench]

I've never heard of a scroll compressor,tell me more.

 

[L31MaxExpress]

I've never heard of a scroll compressor,tell me more.

A scroll piston does not use pistons, the aftermarket has come up with a housing to mount a scroll compressor into a R4 case and unique size making it a bolt in place replacement.

 

[bluex]

Oh and yeah, orifice is in the condenser, that change happened back in '91 IIRC. I don't know much about converting to the parallel flow condensers other than I just recently read some claim that you can't flush them. Any thoughts on that?

Richard

the passages in the parallel condenser are to small to be flushed. If a compressor failure happens an distributes debris through the system it will need replaced.

They are needed though for proper system performance with 134 or hfo.

 

[454cid]

A scroll piston does not use pistons, the aftermarket has come up with a housing to mount a scroll compressor into a R4 case and unique size making it a bolt in place replacement.

Aren't they basically a small whipple charger type mechanism?

 

[454cid]

Any chance you could "boneyard" a clutch for the original compressor, or maybe the whole compressor? If I could keep an R12 system, I think I would. I remember them working super well when I was a kid. It's my understanding that R12 isn't really all that expensive compared to some other refrigerants.... I might actually be able to get my hands on some.

 

[Orpedcrow]

IF you can find it, the REAL r12 Freon I’ve seen $60-80 for a 12oz can. Freeze12 and a bunch of the “substitutes” are just that, Substitutes and don’t provide the performance Freon does.

I’ve used a bunch of GPD hvac stuff and have had no issues.