Evening everyone!

I'm gonna cut to the chase.. I'm a hefty fellow, it's getting hot (90*), and heat sucks. I like Fall and Winter for a reason because it's easier to heat my fat **** up than it is to cool it off.

Insert my Jeep. I commute 160 miles daily with my 2012 Optima, but my wife drives the Heep during the week to save wear on her current (soon to be replaced as soon as we move [which in itself is a THANK GOD because 160 miles a day sucks) Prizm. I also drive my Jeep when home and on the weekends because I love my Heep. It's a 91, and the A/C never worked since I bought it 3 years back. It was only recently I got the ***** to try turning it on (for some reason I was afraid compressor would seize, something would pressurize, explode, ermahgerd!... even though I've used defrost many a time and the compressor/e-fan always kicked on as it should... der der der) and watched as, WOULDNT YOU KNOW IT, the compressor kicked on as did the e-fan just no cold air. I hear no noises minus the empty expansion valve hiss noise at the drier (research has yielded that upon fixing and re-filling the system this will stop). SO, given my '91 used R-12 and I have ZERO access to expensive R-12 and I don't want to try Freeze 12, I will convert to R-134a. BUT!! I will be doing this as properly as I can, not just tossing on the adapters and filling it with freon.

**NOTE! I am aware through research that R-12 is a better refrigerant than R134a in our systems; but please don't tell me to keep R-12. R-134a is the current standard right now and is cheap. I just want to be comfortably cool... I don't need it to snow out my vents even though that would be pretty cool.... Pun intended.**

So, to begin. The compressor seems sound and kicks on with no grinding, bucking, etc. etc. and cuts off when switched from A/C or Defrost. I figure the system is empty of freon at this point. I do plan to use the R-134a at AutoZone (the conversion stuff that says is compatible with remaining R-12 oil in compressor) but will be utilizing NAPA adapters (need 90*) and will be using a vacuum pump to get all moisture and air out of the system as well as to see if I have leaks and if so how bad. I will be replacing the o-rings at all places as well as the drier. The condenser and evaporator core will be flushed individually before being reconnected and vacuum drawn.

Here's the questions:

1) Every R-134a can I find always says oil is already in it. Should I trust this, or should I buy oil and if so, should I introduce via the gauges vacuum line (middle hose) or is there a port on the compressor? Also, do I need to add oil to the evap core?

2) Where can I get an A/C o-ring kit? Where are these various o-rings located (a/c line ends, drier connectors, etc.)?

3) I am hoping I can get away without buying new hoses. I understand at times you can have them rebuilt at shops? Anyone done this?

4) The places on the condenser where the lines hook up look kinda rusted. Cause for concern?

5) Is there a non-UV dye you can use to detect any leaks? I don't have a UV light.

Any other advise is always welcome. Once I get all the info I need, I will get needed parts and get this thing done. Will be doing a write-up on it.

Much thanks!

 

My guess is most auto parts stores have the o-rings (they're green, iirc). When we did our a/c overhaul, all the new parts came with new o-rings. I'd suggest u also replace the orifice tube as it is a filter. We flushed the evap and cond internally with a/c flush and blew them out with compressed air. After adding the precise factory spec measured PAG 100 oil to the system we buttoned it up and took it to a a/c shop to have a vacuum pulled and 1.25 lbs of r134a (no oil) refrigerant. FWIW, I've done 2 r-12 to r134a conversions and I think the r-134a is just as good as r-12.

 

Good to hear!! Thanks for the quick response! Will def get a price for the orifice tube as well. Now, correct me, do the older systems like my and I am guessing yours have an orifice tube in lieu of an expansion valve?

Was discussing A/C with a friend of mine a minute ago and that came up.

Thanks again!

 

Why not just fill with freeze 12 a lot less costly ? Been running it in mine no issues what so ever.

 

If your looking for vehicle specific parts id look at jeepair.com i recently bought fittings and a vehicle specific oring kit. They are also very good on prices.

 

I don't know specifics for a '91......our '98 uses a "liquid line" that contains the orifice tube. Gotta buy the whole liquid line to replace the orifice tube.