Lon

I am converting my AC from R12 to R134. It was leaking and contaminated so I figured I would change the expansion valve (leaking) and dryer and convert all at the same time. At this moment I have the expansion valve and dryer removed and the lines to the compressor removed. I intend to blow the out with compressed air (BTW I did have an ac shop evacuate what was left of my freon).
My question is this; Do I have to change the type of oil in the compressor? I have been told that I should. But I though I read somewhere where Adrian said that Porsche aticipated the change to R134 and that was not necessary.

I really hat to remove the compressor as it seems it will be almost impossible to get the nuts back on (on the back 2 bolts)

Please provide guidance
Thanks,

Lon

pete000

I did my old Vanagon and the kit I purchased from the auto parts had the oil already in the freeon.

springer3

If the system is contaminated (see any dark oil?), it will need to be flushed. There is a commercial product for this purpose. I used brake cleaner with good results before I found the commercial flush. I think they are the same solvent. Flushing is a good idea even if you have the compatible oil. It lets you get the oil charge exactly right, because you start at zero oil in the system.

I have connected service hoses to a propane tank to give the system a final flush and blow out. I charge with the tank inverted to get liquid into the lines. It boils all the way out, and leaves the system nice and clean. Please use lots of ventilation and no smoking!

Good luck

Colin 90 C2

Can you elobarate on what you mean by using Propane?
Are you filling the system with propane first, then evacuating?
What do you mean by it boils all the way out?
I'm assuming you put the propane in before an oil charge?

I guess I'm looking for the most cost-effective( read cheapest) way to flush out an old system.

Thanks,
Colin

Lon

Thanks for the replys guys. I dont see any oil at the moment, but so far I have only loosened the hi and lo pressure lines. I am not wanting to remove the compressor unless it is absolutley mandantory, I cant believe Porsche used nuts on the bottom instead of threading. But I suppose when they built the car it was easy to reach at that stage.

Lon

springer3

I really had no trouble placing the nuts on my 92. They may have changed the design, but I had two of mine back off and I had to find them in the tinwork below. Placing them back seemed unremarkable at the time. I recall using my fingers (no magnets or grabbers needed.

While the system is open, blow the Propane from the charging ports to whatever fittings are open. If you invert the propane tank, the liquid will enter the system, and start boiling as it passes though to whatever is open to the atmosphere. This is done as the final cleaning operation, and is just a DIY way to get the system clean to a professional level. Your post says you want the cheapest way out. Cutting corners will cost you dearly in the long run, so I suggest taking your time, and spending what it takes to get the job done right (even if that means taking the system to a reputable professional). Done properly, the system will last 10+ years, and make the car hold value for having "ice cold" air. Cut any corner, and you can ruin the compressor in the first season or two.

Good luck

Colin 90 C2

thanks, I'll give the propane a try.

I'm doing the system of my Ford work van and I'm only trying to get about 2 years out of it. The receiver/drier dessicant bag blew apart and has sent the dessicant everywhere. Luckily it has clogged at the orifice. I am going to flush the lines, replace the accumulator and change over to R134.

Right now I just have a very oily, sooty mess and am looking for all ways to clean the system.

Thanks for the info.

Colin

John Boggiano

You just read my mind, Lon!

Adrian

Dear Lon,
I am a little confused with your post. Conversion to R-134 from R-12 requires the oil used in the system to be changed. This is 100% correct.
The receiver dryer has to be replaced as well. This is all in the book.
The entire system when re-assembled has be to evacuated again and all the remnants of the R-12 and lubricant removed. The system is then recharged with R-134 and the new oil which is mixed together before it is added to the system. There is no oil resevoir in the compressor if that is what you are asking.
You must do this properly otherwise all your efforts are in vain.
Do not forget to replace the mounting bolt on the expansion valve to the new long one.
Ciao,
Adrian
964C4

ulfpc

A little question.
From what year does the 964/993 come with R-134?
//ulf

Lon

Thanks for the replys .
So , other than the R134, the compresser doesnt have any PAG or Ester oil?

On, the nut issue, I looked at mine again just to be sure and without removing the fan and shroud I absolutley cant even see the nut in the back , closest to the shroud.
But if there is no oil to change then I guess there is no worries.


93 models had R134
Lon

Adrian

Dear Lon,
Make sure you get R-134a oil. R-134a is not compatible with the oil used for R-12.
Ciao,
Adrian
964C4

John Boggiano

Lon - If you can't even see that nut, I think it's been replaced with a smaller than standard one.

I think it should be a large, square one. I manage to wedge mine with a socket wrench handle, when I need to make an adjustment. The others had enough 'bite' to not need holding, fortunately.

Lon

Thanks for all the help guys. This project is all wrapped up and blowing cold at 49 degrees.
Here is a summary of my DIY; I replaced the expansion valve (man what a headache, would have been easier with gas tank removed or tiny tiny hands) and reciever/dryer , O-rings, R134 service valves. Then I took it to a local shop and had them use vaccum tp purge th compressor of remaining oil and replace it with Ester, then Charge the system with R134.

I appreciate the help. the next project starts next week, Clear lenses and bumperettes.

Thanks again,

Lon

andrew911

ulfpc- I have a 1993 964 with the 134a. I believe that's the first year....maybe some 1992's??? There should be a tag somewhere on your compressor/engine compartment that says which kind of freon your system is.