AC compressor port on back left? Leaking from snap ring - what is it?

[1998_K1500_Sub]

I wired the HP switch in series with the LP cycling switch and have been running it for a couple years now with nice cold air and no issues

@454C2500, something to consider is to wire a switch in series if it's not already, as @PlayingWithTBI notes.

On a related note, what ARE those wires pictured near the switch that you also noticed (and mentioned) in your prior post? I wonder if they went to the high-pressure cut-out switch, and somebody wired around that switch (maybe because the high-side pressures were excessive because it had been converted to R134a, and the switch kept cutting-out?).

 

[packer0440]

On the connector itself:

If your Climate control has the "max" or "Rec" option, this does not need to be plugged in (some new compressors have a plug in place of it). If your climate control does not have the max or recirculate option on it, the switch is needed as others have said. Another note; it looks like you have a 1 pin connector there as is. This usually breaks when removing it, and the 1 pin connector is discontinued in favor of a 2 pin connector. You will need to buy both ends of this new connector and connect one of the wires to ground to get it to operate correctly (I believe this change occurred around 1989 or 1990).

 

[PlayingWithTBI]

If your Climate control has the "max" or "Rec" option, this does not need to be plugged in (some new compressors have a plug in place of it). If your climate control does not have the max or recirculate option on it, the switch is needed as others have said.

Yeah, I neglected to mention that.

You will need to buy both ends of this new connector and connect one of the wires to ground to get it to operate correctly

As GM originally designed it yes but, you still won't have high pressure shutoff protection if you do. It needs to be in series with the LP Cycling Switch.

I wonder if they went to the high-pressure cut-out switch, and somebody wired around that switch (maybe because the high-side pressures were excessive because had been converted to R134a, and the switch kept cutting-out?).

Yeah, that needs to be checked out.

 

[1998_K1500_Sub]

Everyone: Didn't R134a retrofits require replacement of the hoses, i.e., to a less permeable type, to mitigate through-hose leakage? I seem to remember in the 90s the "talk" was that the hoses and O-rings needed to be replaced to keep the R134a leakage losses in check.

@454C2500, can you get a decent picture of the condenser? I'm wondering if it's a tube-and-fin type or an "improved" design.

If tube and fin, you might consider replacing it (I would) with a newer design.

If you don't have the OE fan shroud (I think I see it in your picture), consider replacing it with a junkyard find.

If the fan clutch isn't moving enough air through the condenser, then it's item to consider.

I see you're in DC, so at least you're not living in Florida heat / humidity.

I understand these things cost time and money, so nobody's going to be offended if you don't act on every suggestion

 

[PlayingWithTBI]

Everyone: Didn't R134a retrofits require replacement of the hoses, i.e., to a less permeable type, to mitigate through-hose leakage? I seem to remember in the 90s the "talk" was that the hoses and O-rings needed to be replaced to keep the R134a leakage losses in check.

Not that I'm aware of. I didn't replace any hoses when I did my upgrade about 12 years ago. Recently I replaced all the components,not including the evaporator. I did do a thorough flush through it and the hoses/lines again.

 

[1998_K1500_Sub]

Not that I'm aware of. I didn't replace any hoses when I did my upgrade about 12 years ago. Recently I replaced all the components,not including the evaporator. I did do a thorough flush through it and the hoses/lines again.

This hose "concern" I mentioned might be an artifact relevant to the much older R12 systems, e.g., from the 70s, when converting them to R134a. Those cars were still in service when R134a was being phased-in and R12 phased-out (early 90s), and there was much discussion at the time about how to make the change to R134a and / or alternative refrigerants such as blends (note [1]). Your '88 was bit later and perhaps by that time the EPA (or...?) had caused better "barrier" hoses to be used.


(edit) Ah, here's the issue with hoses and leakage. It has to do with nitrile hoses vs. "barrier" hoses (note [2]).

(edit) Also an interesting discussion in the CK5 truck forum by a member named "MaxPF" about R134a retrofits (note [3])


NOTES:

[1] George Goble, Purdue University, creator of GHG-12 an R12 replacement, which later became known as R-406A. https://en.wikipedia.org/wiki/George_H._Goble

[2] Frequently asked questions about R-12 (Freon (c)) and alternatives

Corvette Legends Club

[3] Air Conditioning in an 89 Suburban, see post by "MaxPF" https://ck5.com/forums/threads/shee...-conditioning-in-an-89-suburban-v2500.231624/

 

[OLD BLUE 88]

I had that issue on my 88. I replaced the orifice tube with one from a 99+ (ADO-15-5378 at Summit Racing), a Spectra Premium parallel flow condenser, an accumulator/drier, and a Murry high pressure switch (35961 from O'Reilly's) which goes on under 200 PSI and off @ 430. This HP switch blew out of the compressor (sounded like a shotgun) when I started the engine on a hot day after driving for a while because, the older R12 systems used a 1 wire switch (NLA) and were wired to close the recirculating air door to help reduce pressures with warmer air (IMO a stupid design). It did not shut off the compressor. So, one ruined compressor later, I wired the HP switch in series with the LP cycling switch and have been running it for a couple years now with nice cold air and no issues

I wound up reusing the clutch off that compressor because the new NAPA compressor I got smoked its clutch within a week due to its air gap being too wide (~0.080"), it s/b 0.020" - 0.030" IIRC. YMMV

In reference to wiring HP sw to LP sw in series. Please elaborate. Run the HP wire that I grounded to the positive on the positive on the LP switch?

I have an 88 that has been converted. I grounded the second wire coming off the HP sw on the back of the compressor and the recirc door would activate when the fan was on high. Had to recharge the system, now it seems the actuator is not getting a signal.

When system leaked down, recharged, checked for leaks, none. Tech said his old 88 would do the same. Suggested a recharge every year. Said the R4 compressors don't like the new gas.

Also, having no luck finding a fresh air/recirc actuator for an 88. The Dorman actuator from parts house worked initially, but when I called Dorman directly, they stated they don't even make one for that application. As of now, I've removed the actuator and wired the fresh air door to recirc sense it's starting to warm up here in Texas. Open windows will suffice until I get this sorted out.

Thanks to all for helping us keep these old trucks in service.

 

[PlayingWithTBI]

In reference to wiring HP sw to LP sw in series. Please elaborate. Run the HP wire that I grounded to the positive on the positive on the LP switch?

I have an 88 that has been converted. I grounded the second wire coming off the HP sw on the back of the compressor and the recirc door would activate when the fan was on high. Had to recharge the system, now it seems the actuator is not getting a signal.

Here's a thread I started which contains your questions on post #22 with a diagram I drew up. The main subject was about not getting enough voltage to the compressor clutch to keep it from slipping.

Swapping the Clutch on an R4 A/C Compressor

The other day when I was waiting for curb side delivery at Total Wine my A/C started blowing warmer to the point it was cooler than the vent but not cool enough to keep me from sweating. It got a little cooler when driving home on the freeway then, when I got off at my exit it started blowing...

www.gmt400.com

Then, at a later date I decided to clean it up and add more capacity for upgrades, HTH

Electrical Upgrade? Just do it!

I was looking under the hood of my truck and decided the Mickey Mouse wiring I did for my sub woofer and A/C compressor coil looked like crap. If I wanted to do a "4 Hi" mod or add something else, it'd get even more congested. You can see here the way I tapped the in-line fuses and mounted the...

www.gmt400.com

Edit: If those links don't work for you, let me know and I'll delete the https stuff at the front.

 

[454C2500]

I do have a recirc button and noticed some replacement compressors have that switch port plugged off. If I understand you guys I can buy a replacement 2 wire switch and swap it in just to fix the leak. Wire it in to low pressure switch or I can just use the replacement switch as a plug and don't wire it in?

 

[PlayingWithTBI]

I do have a recirc button and noticed some replacement compressors have that switch port plugged off.

Yeah a lot of them don't come with the switch since they're trying to cover different applications/years. You need that switch or you have no means of protecting your system from over pressuring. Since you have the recirculate button, hook the switch up and see if the compressor runs(after charging the system). Then disconnect the switch and see if it doesn't. If it keeps running, you need to find a wiring diagram and troubleshoot it until it works properly.