1986 Corvette R-12 to R-134a Conversion

[kenlou]

Remember, I am not a pro here, so:
1. If I don't have the high side adapter to use with the injecter, can i just remove one of the switches mounted in the high pressure liquid line to be able to screw onto one of those ¼” valves to inject the PAG oil? Would that be OK?
2. After adding the oil, start the vacuum pump and pull a vacuum again, but only open the low side of the gauge set?
3. After pulling the vacuum, introduce the refrigerent into the high side as a liquid with the can inverted and keeping the can warm with the hair dryer?

Does this sound about right? Plus you gotta remember, I am 68 and a by product of the sixties, so I just want to double-check.

[tbirdtbird]

Yes that sounds right.

I double checked my oil injector. It has a 1/4" female flare fitting on the end. And I have a large assortment of adapters to lock onto hi and low 134 ports, so I just selected the correct adapter to get onto the hi side port. I don't use this injector often so I had to double check how I rigged it.
If you can remove that switch w/o losing vacuum (we are assuming there is a schrader beneath it), then what you describe will be fine

And ask all the questions you want, that is why we are here

[DetroitAC]

DetroitAC, the system is sitting in vacuum right now. How would I pull a vacuum on just the low side?

All I meant by that is to pull vacuum in a place that isn't full of oil. If you open a high side line and fill it up with oil and then hook your vacuum pump to the high side connector on the same line, you will just pull all the oil out into your vacuum pump, it will come out with the initial large flow of air. If you pull vacuum from the low side port only, the oil will get distributed around a bit and likely not be sucked out through the low side port.

If you pull a vacuum on either side, you are evacuating the entire system.

[kenlou]

DetroitAC, the car has been holding at 210 microns for over 24 hours now. I will be injecting that oil in today. How long should I run the vacuum after injecting the oil? I will be adding a holding charge of 24 oz afterwards.

[JohnHere]

My injector came only with a low side fitting, and I changed it over to a high side fitting, but I don't remember what I did, I'll have to check it out.
Why the manufacturers of these things think it is a good idea to inject oil into the low side of a running system is beyond me....most people do NOT want to slug their compressor with oil or any liquid. Perhaps JohnHere could comment.

Right...I don't think I would attempt to inject oil into the low side of a running system, either.

Since the OP already has the system in a deep-vacuum state, I think I would let the existing vacuum pull-in the oil from either the low or high side with the compressor off, and then—since we're dealing with temperatures in the 40°F range, add perhaps a 20-percent charge (two cans or about 24 ounces, as the OP said). The remaining vacuum should pull in at least that much refrigerant. Then finish charging it in the Spring when the daily temperatures warm to about 80°F.

With this method, there will be no need to re-evacuate the system now.

[kenlou]

JohnHere, after I inject the oil, are you saying that the existing vacuum should pull the charge in? I won't turn the vacuum pump on again after adding the oil?

[tbirdtbird]

I am not John, but I think you could do it either way, Detroit's or John's. Detroit is just trying to get the dissolved air out of the oil. We deeply respect his experience. He is suggesting you run the vac pump for another hour if you read his post closely. In truth, prolly no one does this, tho.
I think the call is yours.
And I personally would still inject into the high side. That way you know it won't be going anywhere near the compressor. If in the low side, you have no idea where it will end up

[JohnHere]

JohnHere, after I inject the oil, are you saying that the existing vacuum should pull the charge in? I won't turn the vacuum pump on again after adding the oil?

As said, maybe yes, maybe no. Your call.

As also said previously, I wouldn't leave the system in a vacuum state over the winter. If you do evacuate it again, be sure to put in that partial charge now.

[JohnHere]

It seems to me like your project is becoming more complex than it needs to be. Just trying to save you some work

[kenlou]

It seems to me like your project is becoming more complex than it needs to be. Just trying to save you some work

You are right. I am almost there and thanks for your help