Automotive Air Conditioning Information Forum

66 Chevy C10,
Factory TXV system,
134a,
Aftermarket A6 compressor replacement, (S6, Pro6TEN)
New Parallel flow condenser, hoses, TXV, evaporator and dryer,
Low side: 20-25,
High side: 250-300 and climbing,
80-90 degrees ambient,
@1,500-2,000 RPM
Electric radiator fan and 3' diameter fan at grille.

Based on the pressures and the lack of cooling could be a restriction? Everything is new so I doubt there's debris causing the restriction. Compressor has no abnormal noises. Could it be the TXV? I did a search and saw that a slow pressure equalization after turning off the system is an indication of this. After turning it off the low side immediately goes to 70ish and eventually goes to 90ish, but the high side is extremely slow to fall. After several hours it's staying at 150 psi. The sight glass is all bubbles/foam when running just for reference... I know you can't rely on it for a charge indication.

The TXV is buried inside the evaporator case so I want to make sure if there is something else to look at first.

The radiator fan does blow air towards the rear of the car, correct?

Yes.

No POA Valve?

No.

How many ounces of refrigerant?

If you had a restriction, you would have a freeze up at the restriction point. Mist the condenser with a hose and see if high side psi drops. It may be that you have not enough refrigerant in the system and not enough air flow across the condenser. You can test the TXV operation by alternating placing the sensing bulb in ice water and warm water. Give the bulb time to react. Also make sure the drier is connected in the proper direction and the condenser hoses are in proper location. You stated the parts are new so start rechecking and thinking out of the box.

New Parallel flow condenser
Low side: 20-25,
High side: 250-300 and climbing,
80-90 degrees ambient,

Leaning to low on refrigerant.

What has the place you got the parts from suggested? How much oil was used? Did you flush the old oil out of the system?

Receiver / Dryer installed with flow in the right direction?

Update:

The assembly manual states 48oz R12. I charged it with 40oz 134a. I initially started at the lower end and crept up to 40oz. 10oz oil according to assembly manual. All system components are all new; no flushing was done, although flushing to remove any stray foreign objects would have been a good idea...

Static pressures still didn't equalize after 2 days. 85 and 125.

This time I noticed soon after starting the system the low side almost went to 0. The high side immediately climbed towards 200. Vent temps, feeling by hand, actually felt cool.

After stabilizing pressures were 20 and 300 and climbing. Vent temps warm.

The condenser outlet is almost as hot as the inlet. Can touch it for less than a second.

Sight glass foamy. Drier refrigerant flow is correct as are all hoses.

I can't test the TXV during operation as it and all other hoses/components are buried in the evaporator box. I can't see any hose temp differences. Everything external in the engine compartment is hot.

After stopping test pressures initially stabilized at 115 and 400. 30 minutes later 110 and 275.

I forgot to mist the condenser to see what pressures would have been.

Evaporator outlet going into compressor very warm, not cold like I believe it should be, correct?

One that I noticed was that all diagrams I see have the TXV inlet at the end and the outlet is at the side. Mine is reversed as it was from the factory. Would that make a difference? See photo. There was no insulation on TXV bulb. Unfortunately, I didn't put any on either.