Another AC conversion question

[Jskingry]

Hello all,

I am new here as I just purchased a 1993 K1500 4WD with the 5.7l. The truck runs great but needs a few things here and there including the air conditioning.
The AC Blows inside compressor cuts on etc. The condenser looks rotten, I mean it's in bad shape. So I was looking deeper into doing a full conversion but as I examine parts it looks like the following parts have been converted to R134 compatible parts already:
Accumulator/Dryer is newer looking with a sticker on top that says compatible with R12 and R134a
The lines all appear newer and have R134a fittings
Compressor looks original but no "obvious" leaks

So my thoughts are this, get a new condenser and the flush the system and pull a vacuum to see if there are any leaks once the new condenser is installed. If no leaks then use an ester lube and charge the system with R134a.

Does this sound like the correct route? Do I need to flush the system or just test for leaks once I replace the condenser?

Thanks in advance for any help!

 

[Schurkey]

Is there any pressure in the system now? If so, use a refrigerant leak detector to begin with to check for leaks.

Apparently the system already has R134a in it, so flushing is sorta optional--it should already have the correct oil (assuming the guy who converted it did a decent job, which is not guaranteed.) The screen on the orifice tube will tell you how much debris is circulating in the system.

You can't flush the system with the receiver/dryer/accumulator connected. Best practice is to replace the receiver/dryer.

"I" woud replace EVERY O-ring in the system and also the orifice tube. Nylog Blue for O-ring lube.

I haven't researched condensers. You may want something "special" for R134a.

 

[1998_K1500_Sub]

So my thoughts are this, get a new condenser and the flush the system and pull a vacuum to see if there are any leaks once the new condenser is installed. If no leaks then use an ester lube and charge the system with R134a.

I don't use Ester oil, it seems like a crutch. I can see how some service shops don't want to stock all grades of oil and simply use Ester.

When doing the system myself I use the proper grade of PAG (from a new or recently opened bottle).... that's whenever I'm "oil balancing" an existing system or re-filling a clean system.

 

[Erik the Awful]

"I" woud replace EVERY O-ring in the system and also the orifice tube. Nylog Blue for O-ring lube.

+1. The last thing you want is to do great work and get the system running nice and cool and then next year find it empty.

 

[Ranger550]

I don't use Ester oil, it seems like a crutch. I can see how some service shops don't want to stock all grades of oil and simply use Ester.

When doing the system myself I use the proper grade of PAG (from a new or recently opened bottle).... that's whenever I'm "oil balancing" an existing system or re-filling a clean system.

Yeah, there are only three grades of PAG oil, I believe: 46, 100, and 150. Seems like a cop-out to use Ester oil to me too.

When I converted an 1988 GMT-400 to use R-134A I replaced the receiver-dryer, a new orifice valve. Used PAG 150 oil, not Ester oil. Got the cab temperature down to 42 F in the center console. Marked the engine compartment with "R-134A" so anyone could easily know it was a conversion to an updated A/C system as well.