1996 C1500 Reg Cab AC not working - what all do I need?

Stringer

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Thanks for the info 1998!! I feel like ill be an ac tech in no time lol. this is the area under my compressor. Looks like it had a leak of some sort. Or could be that previous owner sprayed belt dressing and it did look like an explosion under the hood, it was even on the outside fenders. The area under the compressor, right behind the ribbed pulley is gunked with alot of crust tho. Does this look like a full replacement to you?

I was looking up the high side valve and it looks like its calling for a GPD 1311422 and not the 5811340 unless im mistaken? Should i look into replacing 2 sensors as well?

Also, was looking at this compressor, does this look like a good choice? i assume its a sanden knockoff.
COMPRESSOR

Isnt there another part under the dash i would have to replace? i cant find the name of it right now. Thanks!!!
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Stringer

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i have the engine cowl, grill, sepantine pully and idler off the truck. if it does look like the compressor is bad, would it be ok to remove it along with condenser, accumulater and lines even tho i have not ordered the parts yet (wanted to confirm that the compressor i linked to is a good idea, and if there is a part im forgetting about like an evaporator or something?)? would it be ok to remove and cap off somehow for a week or so?
 

1998_K1500_Sub

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would it be ok to remove it along with condenser, accumulater and lines even tho i have not ordered the parts yet (wanted to confirm that the compressor i linked to is a good idea, and if there is a part im forgetting about like an evaporator or something?)? would it be ok to remove and cap off somehow for a week or so?

The AC system should be / remain as clean as feasibly possible.

Others will likely tell you it's OK to cap off the system, at least for a short while. I personally don't like to do it (and haven't), because I do not want to invite contamination. You might say "New-in-the-box parts are effectively capped-off, so why not leave existing parts capped under the hood?" Well, the parts under the hood already have PAG oil coating them (e.g., the inside of the evaporator) from their prior service; PAG has an affinity for water (humidity) and PAG slowly turns to goo when exposed to moisture. Capping off the parts isn't going to prevent them from breathing, e.g., with changes in temp or barometric pressure (unless you "seal" them off, not just "cap" them off) and "breathing" can allow moisture access to the PAG that remains in those parts. Too, small particulates may ("may") enter as well as the parts breathe.

Arguably, if the components are flushed before returning them to service, any oil and small particulates would be removed (if the flush is expertly executed and completely effective). But I would rather keep the components clean by simply not letting them get dirty in the first place.

My $0.02.

Other factors regarding "is capping acceptable" IMHO would be (a) is the truck being used while capped, (b) are you in a dry climate, (c) how long will it be capped, (d) is there a lot of airborne dust? If (a) is no, (b) is yes, (c) is a maybe a week, and (d) is no, then I might cap them for a time.
 
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1998_K1500_Sub

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This is the area under my compressor. Looks like it had a leak of some sort. it was even on the outside fenders. The area under the compressor, right behind the ribbed pulley is gunked with alot of crust tho. Does this look like a full replacement to you?

Oil can leak from the shaft at the front of the compressor and get slung by the pulley. What you're seeing on the fender and area nearby may be just that... slung oil.

The HT6s will also leak in the middle where there's a seam. Look for dirt / oil "under the belly".

But if it's the original compressor, I would be inclined to replace it unless there are budget concerns.

On a different note, I've attached a few files which you might find relevant. Among other things, in them ACDelco recommends using mineral oil instead of PAG to lubricate the O-rings. I use neither; I use a product called Nylog Blue

 

Attachments

  • AC compressor oils - Delco TechConnect.pdf
    28.3 KB · Views: 6
  • Compressor replacement_ 96 GMC K1500.pdf
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  • Lubricating AC fittings - ACDelco TechConnect.pdf
    26.6 KB · Views: 4
  • Oil balancing - ACDelco.pdf
    50.8 KB · Views: 2
  • AC lubricantguide4.pdf
    320.6 KB · Views: 4
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1998_K1500_Sub

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I was looking up the high side valve and it looks like its calling for a GPD 1311422 and not the 5811340 unless im mistaken? Should i look into replacing 2 sensors as well?

That GPD 1311422 kit gives you the valve parts you need. Also take a look at RockAuto's site and see what they show. Look at the pictures there and compare.

You'll also need a Schrader valve tool to remove / replace the OEM valve.

Of course, if you buy a new set of hoses, they may come with the new valves. As for me, I re-used my hoses in the engine bay... took them off the vehicle, cleaned them thoroughly with flush, let them "dry" and re-installed. I wouldn't try to "flush" through them while installed in the system, on the vehicle, but flushing them individually after removal is acceptable IMHO.

I wouldn't start replacing the "sensors" yet. Those are simply on/off switches and are pretty simple parts, so I wouldn't replace as a routine matter.

I have, however, had a low-pressure compressor cycling switch (lives on the accumulator) fail "closed", causing the compressor on my Suburban to run continuously, so switch failures happen.
 
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1998_K1500_Sub

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Also, was looking at this compressor, does this look like a good choice? i assume its a sanden knockoff.
COMPRESSOR

Isn't there another part under the dash i would have to replace? i cant find the name of it right now. Thanks!!!

I don't have an opinion about compressor mfgrs. I can tell you I've used a Sanden on my Suburban and a Denso on my Honda. There are knock-offs around, that I know; they may perform well.

You might want to try the guy at ACKits.com. The last time I looked he sold both Sanden and knock-offs, and he's likely got an opinion. Give him a call, he was responsive to me when I had questions.


Your decision to replace the compressor may depend on your usage. If you're in AZ / CA / FL and running AC most of the year, buy the best compressor. If you're in MN / SD, different story.


There's no "part" under the dash of concern, here.
 
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1998_K1500_Sub

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When you install the new compressor, lay it on the mounting pads of the supporting bracket (on the engine) and see whether it "rocks" or not. If it "rocks", shim or file the mounting pads until it sits flat without rocking.

The HT6 compressors in particular didn't handle the "twist" from mis-aligned mounting pads, as it would precipitate a leak at the mid-body seam.
 
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1998_K1500_Sub

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Budget fix:

It isn't always a requirement to replace each and every part.

There's another approach to this problem that I'll entertain in which you check the system to see if it's got some residual pressure... on the order of 10psi or more. If there's pressure it means the system is still reasonably tight (although it won't run) and more importantly hasn't had a chance to "breathe".

If residual pressure exists, bleed off the pressure and then check the orifice tube's screen for debris and look closely at the oil. If no debris, etc., is on the screen and the oil is clean and clear, vacuum down the system for a LONG time (to pull any residual R134 out of the oil, so you can ascertain the system's air-tight), shut off pump and close the valves on the gauge set, confirm that it holds vacuum (say, for overnight or longer) and if so then recharge and see how it runs.

This wouldn't be my favorite solution (I tend to throw money and my time at things) but it may be quite acceptable.

As long as the system is clean and the oil is clear, you're in great shape. Almost everything IMHO can be reused.

If you can find a leak, fix it. Look for oil / dirt on the condenser (indicative of a leak and replacement), compressor (ditto) and all fittings. Any leaky fittings can be fixed with new O-rings.
 

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  • Dirty and clean orifice tubes.jpg
    Dirty and clean orifice tubes.jpg
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Caman96

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New compressor, new hoses, orafice, pressure switches, pag oil and accumulator. Assess your condenser. Install parts, have it charged and enjoy. Don’t over complicate.
 
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1998_K1500_Sub

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Think it through, do it to the best of your ability, and learn something in the process. Anyone can spend money and throw parts at a job.

Here are a few relevant docs from Sanden and one from Denso for your reading pleasure.
 

Attachments

  • Sanden Compressor_Installation_Instructions.pdf
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  • Sanden SD_Service_Guide_Rev_2.pdf
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  • Denso compressor installation guide.pdf
    1 MB · Views: 2
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