I keep reading the R4 compressors "Do not like Ester oil."

I also read that GM's proprietary oil turned out to be a PAG120 of sorts.

My air conditioning is almost all the way sorted out but I noticed a LOT of load when I engage it and I think it may be minorly starved of oil.

Should I add in a little bit of PAG 46 to help it out?

1996 4.3 with an R4

 

Well. I did not add any oil.. but I did add 36oz refrigerant to the system.

It appears to be getting cold but I suppose the REAL test will be when it is hot AND humid. Still have not had a really hot day where it will be obvious how well the AC is doing.

Did I overfill it? Should i let out some?

 

Just put the AC on MAX AC and the windshield started to fog up. It Is humid outside.

Is that normal ? About 60 degrees. 92% humid

 

Yeah, you got to keep the wipers going

 

I see. Cool... lol. Literally!

Should I also try the AC and TWO ARROWS setting right next to it instead of just MAX AC (which sets Recirculation automatically?) Sounds like my unit is working properly. And getting really cold.. 36oz put in today on dry system.

 

Just went for a spin. AC seems nice and cool. Car drove pretty smooth.. smoother than it has been.

I sure hope it stays that way.

I didn't check any pressures before i went out.

69 degrees and climbing, 77% humidity. Not HOT out but you can feel that heat creeping. If that makes sense. But not in my truck. Water out of the bottom as normal.. 🙂

 

The air felt pretty good today. It's not hot outside just a little humid. Sat at a drive thru for 30 minutes and played with the switch. I seem to get the coldest air on the TWO ARROWS setting.. then it alternates between if AC or MAX AC but TWO ARROWS, and to my surprise.. gave coldest air. May have tapered off a little bit during the long sit but for a system that wasnt working right (or at all) like a month ago.. it does produce cool air.

Some thoughts I have:

1. Am I overfull.
2. Should I release just a little from the low side port. Maybe even some air comes out. I know you stop when refrigerant comes out. Or do I leave it alone..
3. Was running it all day today a good move. (Idea was to get it all circulated.) It still seems to be cool and produce water when running so I believe it hasn't leaked. Good tests are during day...
4. Will some leak out anyway as it "normalizes" (pressures?)

 

I think I just let some air out of the system but I don't exactly know yet I need to wait for it to get hot outside to see

 

On the can it should say whether the can includes a Sealant and/or an oil. You want to get the can with oil but no sealant. If it is a AC Pro can, it will probably have sealant. That is a problem when you take it to a shop that has a machine that evacuates the AC system. They won't touch the vehicle that has sealant added to the AC system. It is bad for their machinery.

 

Your refrigerant circuit should never have air or moisture in it. Air will disturb your pressures and cooling performance and can kill your compressor. Moisture will combine with the oil and damage the system by forming acid and sludge. You should not release refrigerant into the atmosphere, it’s illegal. The refrigerant is constantly changing in state from a liquid to a gas and back again. Refrigerant in the vapor state is not air.

Not enough oil is bad but that’s rarely the case. Too much oil is common, especially with oil in those consumer refrigerant cans. Too much oil will kill the compressor. The proper oil viscosity is related to the brand of compressor. AC Delco, Denso, etc all call for different oil viscocities. Mixing oil can be bad with certain combinations.

As mentioned the stop leak in those consumer cans is bad. It can plug your system and/or make the system unserviceable by a professional.

The proper way to maintain your system is the careful replacement of lost oil with the proper type and quantity. This is almost always only when components are replaced or after a catastrophic loss of pressure. Stop leak is bad. Moisture and air are bad. The system needs a proper reclaim, verified leak free with a nitrogen charge, verified that it can hold a 500 micron or less vacuum and then charged to the name plate refrigerant weight. An experienced mechanic can top off a charge successfully but you need to be able to evaluate the system properly. The amount of refrigerant in modern systems is very small and overcharged systems are common. Most people assume that all problems are low charge and that mo’ is better. Optimum charge weight is better.

proper charge and function is verified by looking at the high and low side pressures for a given ambient temp and humidity and observing the center vent temp. Not all system work correctly with the same pressures. Honda’s for example have different targets than say Blazers.

i don’t know about the windshield humidity and air conditioning. That usually comes up with leaking heater cores.


George