What's the easiest way to get the nastyness out of the AC? There's no leak, the system is empty, and i looked at the orifice tube which was soaked.

 

AC flush

You can use lacquer thinner, MEK, acetone; NOT brake cleaner, "paint thinner", or anything else that will leave a residue, to clean out the evap, cond, & lines.

Are you changing out the compressor and the accumulator? Those will be all full of the same whatever funk, and aren't easy to clean up.

 

I wasn't planning on it. I can get a new accumulator if that makes things easier. Aren't those somewhat cheap? If so i can just grab a new accumulator and orifice.
Here's what chatGPT says to do. How accurate is he:

• Recover refrigerant (using an A/C recovery machine).
  
• Remove:
  
  • Compressor (drain oil; do not flush).
    
  • Accumulator (discard).
    
  • Orifice tube (discard).
    
• Flush metal lines and evaporator:
  
  • Pour 2–4 oz of flush solvent into each section.
    
  • Use your flush gun with compressed air/nitrogen to blow it through.
    
  • Catch solvent until it runs clean.
    
• Dry all lines thoroughly (5–10 minutes of dry air).
  
• Install new orifice tube and accumulator/drier.
  
• Add correct PAG oil to the compressor and components (see table).
  
• Reassemble the system.
  
• Vacuum the system for 45–60 minutes to remove air and moisture.
  
• Recharge with 32 oz (2 lbs) of R-134a.
  
• Test pressures (typically ~30 psi low / ~200 psi high at 75–85°F ambient).
  

 

I have to ask why? Is dye corrosive? If so, why do new vehicles come with dye in the A/C systems? Evil plan to ruin your A/C after the warranty is up?

 

Dye in the oil is for diagnostics to find leaks easier with a UV light. The dye won't harm the system. Its the oil that's dyed and the system needs oil.

 

Those destructions are mostly on point, with the possible exception of how much R-134A it will need. You'll probably need more than 2 lbs but probably not as much as 3.

If you're changing from R-12 to R-134A for the first time, you need to get ALL the old oil out of the system, as it doesn't play well in the same sandbox as the kind you need to change to. You can take the compressor off and maybe drain it that way, maybe wash it out with solvent a time or 2 (the suction line goes straight into the crankcase, and the pressure line goes to the inside of the shell, outside of the reed valves) and let it drain as well as it can, then pour some of the new oil in it. If you're feeling REAL adventurous you can take off the shell, that gives you access to all the mechanical guts, to clean it out.

The system takes around 6oz of oil; I usually pour about 3 into the comp and 3 into the accum before bolting everything up. I prefer to use the mid grade of oil, something around 90 or 100; there's some that's like 60, and some around 150, and then some in the middle. I think the thick will also work OK with a R-4 compressor if you can't get the mid, butt don't use the thin.

I don't know of any way to get oil out of the accum; it's a filter system, not really subject to cleaning out. Just replace it.

Put in a new orifice tube too. Not worth the risk of the old one having gunk in it and keeping it from working right. For 134A, use the red/orange Frod one; ask for something like a 96 Crown Vic at the parts store.

The dye itself doesn't really hurt anything. The OT will always be soaked with oil, and of course dye, if there's any in there. Butt as cheeeeeeeep as those are it's not worth risking an old one, change it out regardless, if you're already there.

 

Brakleen. They make flush too.