134A conversion oil amount

[565bbchevy]

How many total ounces of Pag 100 oil for a 134A conversion in a Gbody and how does the total get distributed?
This is a new set up with a new compressor that comes charged with 3 oz of oil.

 

[69hurstolds]

According to the compressor label, 6 oz. goes in the total system. Service manual is kind of strange, because it's not really an addition issue there. They'll tell you 3 oz (or whatever you drain out of the old R4 if more than 3 oz) in compressor, 3 oz. in evap, 1 oz. in condenser, and 2 oz. in accumulator. If you add all those up you get 9 oz.,...but at the beginning of the paragraph it says these recommendations are for COMPONENT replacement. So say, if you just replaced the accumulator, you'd pop 2 oz of oil in it and install. Nothing else really matters as long as the compressor gets lubed. But there must be enough in the system to get carried to the compressor. In any case, the manual says at least 3 oz. in compressor.

If'n it were me, I'd do 3 in compressor, 1 in the accumulator, 1 in the evap, and shoot 1 in the condenser on a totally new or flushed out system for a total of 6 oz. If not replacing the condenser, then 2 in accumulator, 1 Evap and 3 in compressor. Then evacuate the pee out of it.

That's just me.

 

[Bonnewagon]

I agree. But the way I understood, when using a new or rebuilt compressor, that you drained and measured the oil just to be sure the right amount was actually in there, and if it is, then pour that back in. And then the other components got their amounts. But if re-using a compressor, you drain and measure just to see what is in there, and if not, then add the amount to bring it up to the required amount. The idea is that a certain amount will puddle in the compressor and if it is NOT there, you add some to bring it up to specs.

 

[565bbchevy]

So the sticker for R12 says 6 oz of oil does that still apply with 134A since you use only 80% of refrigerant compared to R12?

At this point I only plan on flushing the evaporator core and the hoses and hardline, the compressor, dryer and condenser will be all new.

 

[69hurstolds]

So the sticker for R12 says 6 oz of oil does that still apply with 134A since you use only 80% of refrigerant compared to R12?

At this point I only plan on flushing the evaporator core and the hoses and hardline, the compressor, dryer and condenser will be all new.

I don't see why not. Whatever the refrigerant can carry is what it's going to carry, any excess will just be left behind in whatever pool it happens to be in. The amount of refrigerant comparison doesn't really have a lot to do with the amount of oil.

I honestly don't see much of a problem with having a bit more oil in the system, so if you happen to toss 7 oz. in, so what? You just don't want to go below minimum for the compressor's sake. There's nothing else in the system that needs the oil. Some of the oil will get sucked up into the new dessicant anyway.

You're going to probably get different answers to the same question. I put 6 oz. of ester in my 84 when it got converted over to 134a, and had no issues with it until I decided to go back with R12 after the reman compressor sprang a leak.

As far as the oil in the compressor, Bonnewagon , the 85 and 87 Olds Cutlass CSM states that if you pour out LESS than 3 oz. of oil into a measured container, then you put back 3 oz. If you pour out MORE than 3 oz., then you put back in what you measured. But minimum would be 3 oz.

Oh, and make sure your new accumulator has 134a dessicant in it. The original R12 dessicant won't work too well. Most new aftermarkets do, but just make sure it does.

Now, with that said, there's this.....(for a 3rd gen Firebird, but it used 8 oz. of oil in the system anyway)

 

[69hurstolds]

86 monte service manual says something a little different than the Oldsmobile service manual as far as distribution. Why? Maybe because of the longer piping, etc.?

 

[Bonnewagon]

As far as the oil in the compressor, @Bonnewagon , the 85 and 87 Olds Cutlass CSM states that if you pour out LESS than 3 oz. of oil into a measured container, then you put back 3 oz. If you pour out MORE than 3 oz., then you put back in what you measured. But minimum would be 3 oz.

Makes sense. I was going by what instructions came with the compressors. But, yeah, if more came out, put that back. The whole idea is that the compressor only needs a small amount of oil to keep from grenading. But as we know, the oil is carried along with the freon, and tends to puddle at certain points in the system. So the engineers figured out how much oil it needs to fill all the puddle points, get carried along with the freon, and still lubricate the compressor. An ounce too much is no big deal, but too little is a problem.