Is it even possible to get at the low-side AC port?

Z06C5R · 06-07-2008, 04:31 PM

It's 95 degrees and about 1000% humidity here, and I'm in a desperate mission to get my AC working. I took a look at the the system from the top, and saw that someone had converted the high-side fitting over to R134a - wicked cool I figure, the system must have already been converted! I couldn't see the low-side fitting because the under tray gets in the way of the compressor, but I figure it's got to be converted, right?

Wrong! I went out and bought an R134a kit, and when I got the tray off I was greeted by an un-converted fitting. Furthermore, the damn thing is in an impossible place! The mounting bracket it like 1" away from the top of the port! I couldn't even get my charge kit's hook up in there as it is now, so there's NO way it's going to fit once there's an adapter on it! What a wreck!

So, my questions:

> Can I find a single R12 to R134a low-side fitting (in-store, not mail-order), or do I need a whole kit?
> Will I be able to hook up to the system with the fitting installed, or do I need an elbow or something?

mikepellegrini · mikepellegrini's Garage

If you still have any R-12 and oil in the system, you really need to totally evacuate the system with a nice hard vacuum (sucking out all the mineral oil and freon), purge the system, then pull a good vacuum and hold it for 15-20 minutes, then refill with new oil and R-134a (it uses a totally different sort of oil than R-12).

To do it right, you also first need to change all the o-rings and change the drier.

A somewhat easier solution might be to run an R-12 substitute (like Duracool or whatever) that also uses compatible oil.

Duracool uses R-134a connectors (not sure about the other R-12 substitutes) so you still need an adapter. I got one of these - and it works well. I wasn't able to find any locally here, at least.

https://www.ackits.com/pc/35-50003/conversionitems/Low+Side+Conversion+Fitting+%2890+Degree%29

You have to take the Schrader valve out of the R-12 fitting on the compressor before you mount the right-angle adapter.

It's still a good idea to replace the drier (the system will probably cool better with a new drier).

hpservertech · 06-07-2008, 05:45 PM

You really should replace the dryer any time the system is open to the outside. They are pretty cheap so I wouldn't worry too much about the cost of it. Since it sounds like you have a leak I would replace the o-rings too. Also very cheap (and you can get them at autozone)

marky522 · 06-07-2008, 06:29 PM

I dont reccomend running the r12 substitutes, if you want to stay r12, you can get it on ebay or craigslist for about $20 a lb. If you are going to convert, like was stated above, replace the drier, and have the system vacuumed and leak checked. I had an issue with 2 of the 90 degree adapters leaking so i just did a high side charge so i didnt have to use a low side adapter.

Mark

John_AZ · 06:11 AM

If you would like the technical articles involved to convert to R134a=
Click on AC R134A. http://www.the944.com/

John_AZ

Porsche-O-Phile · Porsche-O-Phile's Garage

Low-side port is tricky on the early cars but it can be done.

I actually found an "L" shaped fitting for the port, put it on the compressor, then bolted everything down, leaving the "L" fitting dangling there. I then filled through that and when done, screwed a cap on it and zip-tied it off. Next time I need it, it's there waiting, conveniently accessible.

marky522 · 06-08-2008, 02:31 PM

Quote:

Originally Posted by Porsche-O-Phile

Low-side port is tricky on the early cars but it can be done.

I actually found an "L" shaped fitting for the port, put it on the compressor, then bolted everything down, leaving the "L" fitting dangling there. I then filled through that and when done, screwed a cap on it and zip-tied it off. Next time I need it, it's there waiting, conveniently accessible.

Like i said above, if you ned up having a leak make sure you check that 90, i have had both i installed leak.

Mark

Z06C5R · 05:32 AM

I suspect it's already been converted, not only because of the existing R134a fitting, but also because the drier looks pretty new in comparison to the rest of the stuff in the system. I don;t know why they would have charged it hi-side, unless professional equipment can do that...

Also, it looks like the schrader valve for the low-side fitting is built into the compressor - I assume conversions just screw on over it?

And finally, that 90 fits? looks like it's be really tight if it did.