Identify source of material clogging up AC

[Matthew Jeschke]

I have been diagnosing my AC (2001 Z71 Tahoe w/ rear air), first the front went out, then the rear. Static pressure was low 50 PSI was supposed to be 75 PSI. The compressor kicks on and builds pressure quick but doesn't sustain it, and cycles again quite quickly.

I tore down the system and found debris in the orifice tube and expansion valve. I've an idea of what it is but want to confirm it's not the compressor. It's like hard white plastic bits. Others appear to be dark metal pieces but upon closer inspection are little rubber strips, almost like it pulled sucked in pieces of the o-rings.

I cleaned the system as best as possible with compressed air and brake cleaner. Then I put it back together with cleaned up expansion valve, and new orifice tube. I evaculated the system for 1 hour then it held the vacuum for an additional hour after that. I recharged it with dust off (didifluorethane HFC-152a), a cheap refrigerant, to test it. At first it worked fantastically for about 5 minutes. Then the pressure built on the high side to a whopping 250 PSI and blew the seals out lol

I had suspected this and wanted to capture whatever remaining debris I could before installing a new dryer, orifice tube, expansion valve and seals. Anybody have any idea what this debris is? I'm hoping I don't also need to install a new compressor condenser etc Compressed air flows through the evaporators, and condenser with ease.

PS. This is a continuation of my thread here which isn't labeled appropriately anymore: https://www.tahoeyukonforum.com/threads/front-ac-doesnt-work-back-does.110977/#post-1332869

 

[SnowDrifter]

Not sure what the original source of thr material was. But if something ate itself, you won't ever get all the crap out if the condenser or evaps. Need to overhaul the whole system at that point

 

[Matthew Jeschke]

Not sure what the original source of thr material was. But if something ate itself, you won't ever get all the crap out if the condenser or evaps. Need to overhaul the whole system at that point

A new dryer won't catch that debris? I litterally only found it in the orifice tube and expansion valve. I don't think it made it any further.

I found the error in my recharge. I put in nearly double the refirdgerant I was supposed to. It takes .6 the weight of r124a when charged with r152a.

I will see if any debris is on the orifice tube and expansion valve when o tear it down this time. And am going to pull compressor to drain oil and change it. Then I can see if debris is in it too.

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[SnowDrifter]

Not in my experience, anyway. Compressor grenades. Customer want a cheap fix. Compressor eats garbage still in the system and blows up again. And again. Then they finally agree to do it properly.

Few vehicles have TSBs about it.

You might get further in cleaning by rigging up a recirculating pump/filter setup w/ toluene or MEK. let the thing run for a few hours in one direction, switch, run again, switch, run again, etc until you stop capturing material. Then some more for good measure. When assembling, treat all parts as dry as far as oil requirements. Oh and use the highest pressure/volume pump you can get your hands on.


After giving it some thought, was stop leak used in the system at any point?

 

[Matthew Jeschke]

Not in my experience, anyway. Compressor grenades. Customer want a cheap fix. Compressor eats garbage still in the system and blows up again. And again. Then they finally agree to do it properly.

Few vehicles have TSBs about it.

You might get further in cleaning by rigging up a recirculating pump/filter setup w/ toluene or MEK. let the thing run for a few hours in one direction, switch, run again, switch, run again, etc until you stop capturing material. Then some more for good measure. When assembling, treat all parts as dry as far as oil requirements. Oh and use the highest pressure/volume pump you can get your hands on.


After giving it some thought, was stop leak used in the system at any point?

Honestly not sure about stop leak, I bought at 225k miles without any maintenance history

The sad thing is I am just resisiting what I think maybe the ugly truth about my repair

I actually woundered about a recirculating pump like that, what type will work? I am searching amazon but don't quite know what would work. Also needs an inline (inexpensive filter).

Thanks for the help

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[SnowDrifter]

Stop leak will cause ya nothing but sadness lmao


Honestly just fab something together. Toss in a bucket and let it go. Toss the filter on the inlet side of the pump. Can use a fuel filter

For pumps: Grab a cheapie 12v inline fuel pump. Any that ya use for this, plan on throwing away. Toluene isn't too bad, but MEK is some nasty nasty stuff. Works great! But my god will it clean our your sinuses

 

[Matthew Jeschke]

Stop leak will cause ya nothing but sadness lmao


Honestly just fab something together. Toss in a bucket and let it go. Toss the filter on the inlet side of the pump. Can use a fuel filter

For pumps: Grab a cheapie 12v inline fuel pump. Any that ya use for this, plan on throwing away. Toluene isn't too bad, but MEK is some nasty nasty stuff. Works great! But my god will it clean our your sinuses

Sweet. I will def do that. Where can you buy toluene?

I see pumps here, however, curious how many PSI? They are like 4 PSI for cheap pump on amazon.

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[Matthew Jeschke]

I am atupid torune is paint thinner. I found a 90 psi pump. Thx

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[drakon543]

chemical resistant gloves if you use mek the regular gloves will dissolve/ disintegrate/ melt off your hands. it doesn't bother my hands unless i have a cut but my hands might as well be dried cow hide leather now. im sure it will bother some tho as it is an aggressive solvent.

 

[Fless]

When using MEK you should also wear an approved NIOSH mask; be good to yourself. That stuff can cause permanent lung damage.