Oil Balance Question

[MeteorBurn]

Hello everyone,

I've got a few questions concerning the A/C in my 1998 eclipse. I'm no stranger to working on cars, and I understand A/C is a tricky subject usually left to professionals but I figured with multiple older (90's) family cars that it wouldn't be a bad thing to try and learn.

The A/C has not been working for about 2 years and was empty. I found a few leaks (high and low side schrader valves, o-rings at the ends of the suction line) and repaired them.  When pulling a vacuum I accidentally shut off the pump before I closed the manifold valves on the gauge set and some oil (~ 1 oz) from
the pump was drawn into the system. I know, stupid error. I also think the pump I used (rental) had a defective backflow preventer. 

Long story short I removed the evaporator, compressor and lines. I put a solvent based flush through the evaporator after removing the expansion valve, and blew dried compressed air through it for a good amount of time. I drained the compressor, but I only was able to get about .2 oz of oil out of it. The lines were flushed and dried, and I am replacing the receiver dryer. 

1. I am essentially starting with a dry system. However, I don't believe the condenser took in any appreciable amount of vacuum pump oil. The service manual states that 1.35 oz of oil settles in the condenser, but since the system has been empty is that number accurate? The compressor barely had anything in it. I don't want to flush the condenser because I don't think I'll be able to get all the chemical out. It took a considerable amount of air to get just the evaporator dry. Should I assume there is 1.35 oz, or flushing it is the only way I can sure of the correct oil amount in the system? 

2. I'm finding conflicting information on installing the oil charge. Some manuals state to put the full charge in the compressor, some say put half in the compressor and the other half in the rest of the system. The system capacity is 2.7 - 4.1 oz. The manual uses 3.4 oz as the target amount. Would I be okay putting in 2.05 oz in the compressor directly and assuming there is 1.35 oz in the condenser? 

I greatly appreciate any advice. 

[MeteorBurn]

Thanks for the help. I'm almost finished with getting the condenser out. Evaporator has been reinstalled under the dash.

One other question I have is about the factory specification for the refrigerant amount. The sticker under the hood says 23 oz, while the service manual states the capacity as 24.69-26.10. Would I be okay putting in two 12 oz cans, or should I try to keep the last ounce in one of the cans and put in exactly 23 oz?

[Cusser]

Thanks for the help. I'm almost finished with getting the condenser out. Evaporator has been reinstalled under the dash.

One other question I have is about the factory specification for the refrigerant amount. The sticker under the hood says 23 oz, while the service manual states the capacity as 24.69-26.10. Would I be okay putting in two 12 oz cans, or should I try to keep the last ounce in one of the cans and put in exactly 23 oz?

You'll never get full 12 oz. from a 12 oz. can.
1. You need to purge the hose.
2. Some remains in can.

[GM Tech]

If it makes you feel any better- just know that absolutely every automotive compressor built was installed in its vehicle home with the entire system charge amount of oil in its belly! So I'm not a big fan of oil distribution upon repairs. I worked for Delphi for 30 years and have been in every N. American assembly plants watching the a/c evac and fill- and you can be assured it is this way. So, it matters very little, where you put the oil- just make sure the pump has plenty.

[MeteorBurn]

Just a little update, flushed out the condenser and put plenty of compressed air through it. I used Dura flush II, that stuff evaporated scary fast. Not sure why there weren't any flammability warnings on the can.

Put the oil charge into the compressor, spun the clutch 10 times, and reattached everything else taken off. I wasn't too worried about break in because I wasn't replacing the compressor - nothing wrong with the old one.
One pipe connection on the condenser was pretty much frozen together, and I wasn't willing to heat it up/drill a small hole in the nut, so I left it alone. It's the only o-ring that didn't get replaced, lol.

I then pulled a vacuum for 3 hours just to make sure everything was good. Held vacuum for about 4 hours with no drop. The oil in the vacuum pump got pretty milky after an hour of running so it definitely pulled a good amount of moisture (I changed it before running it again). Rethought my strategy of charging the system with cans and just decided to have a shop do it - it was cheap enough anyways, and I let them know that I put a full oil charge in the system and no additional oil was needed, no problem. I didn't want to take the risk of overcharging or undercharging and making more problems.

Cooling very nicely now. Following the load test from the service manual (windows closed, recirculation mode, max fan speed, front vents only) I got about 49 degrees from the center vents. Temperature in the garage was 85 F with 70% humidity. Does that sound respectable? The thermometer was actually still dropping, it just became very slow. The manual was not very helpful in this regard because it only lists two ambient temperatures, 75 and 95 degrees with no humidity levels mentioned (39 - 46 F being acceptable vent temps). Ironically the manual for another car in my fleet, a 1995 oldsmobile cutlass, lists up to 62 F discharge temps as acceptable at that temperature and humidity.

Anyways, thanks for the help. As an HVAC controls technician I definitely appreciate the complexity of mobile A/C systems much more now.

[Cusser]

Should get even cooler with actual driving !!! Try that !