MainePorsche

Guys,
I am able, and going, to get 1050 grams of 134 placed into an evacuated system.
Do I have to inquire with my local guy doing this as to how much oil is in the mixture that he uses, or do all tanks have a known, set amount of oil to actual refrigerant ? As you can tell I am unfamiliar with this.
Thanks in Advance.
Craig

j.kenzie@sbcglobal.net

No oil in refrigerant stock. It should be added to make up required total.

MainePorsche

Dave,
So when the WSM says 1050 gms for fill, how much is refrigerant and how much should be oil if 1050 gms. is the total ?

j.kenzie@sbcglobal.net

1050 gm is refrigerant. Oil should be something like 240 gm. I don't remember exact amount. Completely separate. Oil tends to stay in the system unless flushed or you have a catastrophic leak. When you replace components there are predictable amounts that each will retain and should be added to system to make up for loss.
Dave

MainePorsche

Thanks Dave. I have had what I believe is a complete evacuation (intentional). I will have to refer to the WSM to see what the oil weight should be. I would imagine it would be documented there ?
So it would be 1050 gm weight refrigerant PLUS the specific weight of oil.
If my local guy asks my what type of oil, what do I tell him ? I have a retrofitted 134 system by Porsche.

GregBBRD

Oh, if it was this easy....

I fix these poor things, every single day, that have been "converted" to R134.....and it isn't cheap.

You know that "evacuated" doesn't remove the existing oil and it must be physically removed? The existing oil, in the system, is not compatible with the R134 Freon and every single tiny bit has to be removed?

And with a 928, this means that the front and rear expansion valves need to be removed, in order to clean out the evaporators?

And you will need to remove the two lines under the car (to the rear A/C) to clean them out?

And replace the dryer and clean the front condenser?

And the compressor will have to be removed and completely cleaned out of all the old oil?

If you know all of this.....

The capacity of oil on an R12 system is 9.3 ounces.

The capacity of oil on the R134 system (used on the GTS vehicles) is 5.2 ounces.

Keep in mind that the compressor on an R134 system is designed for use with R134 oil and the compressor on your existing system is designed for R12 oil. You will have to figure out the difference and add in whatever amount of oil you "think" is correct.

Me.....I never "convert" a car.

I just "fix" the ones that were converted and re-install R12.....which is a much more efficient Freon.

upstate bob

134 requires a different oil than R12. If the dealer changed the system out previously he would have
flushed and changed the oil to the compatible type. In addition he may have replaced some hoses.
Usually if your system goes flat once you won't need any more oil. Look for leaks which leave tell-tale oily traces. If it lost a charge once it will probably do it again. I bought my 79 with an empty(unconverted) cooler and haven't bothered to deal with it. If it's too hot outside I leave it in the barn.

upstate bob

yikes, punched the button at the same time Greg. You are totally correct. I'm not going to bother to try to get any R12. I'm happy to have a lifetime supply now of R22 for my homebuilt heat pump. (water source)
-no I won't try to pour it in my 928

Rob Edwards

Tech spec book says 280 +/- 20 cc of Densoil 6 for an '87. But not if you're going to run r134a, you need the modern equivalent of synthetic Densoil ND8.

The 90-93 Tech specs book mentions the change to r134a but doesn't spec a different mass of refrigerant. The service info does list a much lower oil charge for the GTS (160ml) but that's a different compressor (10PA20c) vs. your 6E171 compressor.

Unless your system got completely flushed while it was completely evacuated (during its presumed proper r134a conversion....), you don't really know how much oil is in there. But as long as A) the system blew cold at some point post-conversion, B) there wasn't some catastrophic compressor failure and C) the system only went warm because of a slow leak, I'd bet it doesn't need much if any oil.


Some old TSB on refrigerant and oil amounts typically in each component of the sytem:

MainePorsche

So, unless physically removed, the oil in the compressor is still present ?
I had to recently remove my fuel cooler. It is being replaced. In doing so, what I believe is all the refrigerant gas was let to evacuate. So am I safe to assume that the oil still resides in the compressor ? I want to prepare correctly for when I visit my local guy who is able to add refrigerant specifically be weight.

MainePorsche

Rob,
Thanks for posting that.
My 134 system has been working fantastic (aside from an electrical issue that kept it from working with the headlight switch turned on, which has now been resolved). As I stated above I know the refrigerant gas had been evacuated with my fuel cooler removal. If all wasn't removed, my guy up here can completely evacuate it. I was just wondering about the status of the oil and what I might need to address regarding it, as well as with what and how much.
Craig

Rob Edwards

Since the section of suction pipe through the fuel cooler is a straight shot and near the highest point in the system, I'd imagine you lost essentially no oil during the R&R. I'd put new o-rings on the ends and call it good.

If your new-to-you cooler doesn't have insulation on it, it's probably worth making it a sweater out of a piece of foam pipe insulation.

MainePorsche

Thanks Rob,
That's what I was hoping you'd say. Tom should have the cooler and new O rings here tomorrow. If it doesn't have the insulation out of the box, I have adhesive pipe insulation waiting at the ready.
I stepped in it while trying to add one of Greg's lines, and ruined the cooler. I had a thread on it telling the tale. Should be good by the end of the day tomorrow.
Thanks again,
Craig

MjRocket

May be a silly question, but what type of refrigerant did an 87s4 come with? R12??

Thanks

MainePorsche

Yes, originally R12.