BigMikeATL

I was flipping through the receipts that I got when I bought my '91 a couple of months ago. The dealer I bought it from had a receipt in there a few small repairs and it said A/C Recharge and in the parts section it said R134, Qty 2.

Now the question is, how do I know what was replaced when it was converted to R134? I don't have any documentation for that?

The fitting on the compressor has a green cap if that means anything. Are there any parts I can look at to see what is what?

Makmov

Not really.

Depends one who did the work and how much of a conversion they thought they needed to do.

For some it's seals and a dryer, some just seals, some it's more.

I just did a dryer replaced a bad hose and charged it with R134... that was 3 years ago and it still blows cold.

I think the green is the original color the converted fittings are larger and black. R134 gauges will not work if it hasn't at least had the fittings changed. Maybe that is all they did.

Vandit

My '91 runs R134. I'm not sure when it was converted, but it cools well, even in Texas Summers. Too bad it's got a slow leak and I have to top it off at least annually.

BigMikeATL

It blows cold but the carfax actually showed the Porsche dealer adding freon 2 or 3 years ago too. So I'd assume there is a very slow leak somewhere.

Is there anything that could be damaged if it wasn't done correctly?

What seals have to be replaced? I went through all of this with my 944 but can't remember.

Makmov

Could be a slow leak that was never addressed.

Yes.

There is a debate about the combatablity between mineral oil and R134a.

Also the system needs to be totally evacuated R12 and R134a are not compatable.

any moisture with R134a makes acid that will eat alu componets.

All of them should be replace when introducing a new refridgerant. Some seal materials will react differently to R12 or R134a, or maybe not react at all.

A proper converson at the very least would be complete set of seals, dryer, completely evac the system and drain the compressor oil.

Recommended new expansion valve rated for R134a some people will recommend replace the evap too. That is gennerally where all the crud and containments seem to end up.

Vacuum the system and recharge.

tbennett017

Redoing the evaporator (though a royal pain) was well worth it. Totally +1 on Makmov, as it was all gunked up and the lower 2/3 didn't even have any airflow through it. Much colder now.