I need help from all XJ users who converted from r12 to r134a or Duracool

My girlfriend recently bought my brother's '93 XJ 2wd for 500 dollars. The drivetrain is in fine shape, and I'm working on all the little things to get it working just right for her. The problem is the A/C has not worked in at least a year, and it's on r12. I had some credit at the local firestone where I had my 2001 XJ 4x4 worked on, so I had them check it out and they told me the following:
They reccomended converting the system to 134a, but the expansion valve (h-block) was clogged, or not working properly, the reciever/drier had to be replaced, and to convert to 134a I'd need a new condensor because the one on it wasn't "heavy duty" enough to take 134a. ALSO, apparantly someone MAY HAVE mixed the R12 with R134a, because the low side (suction) has a 134a fitting, and the high side doesn't. I'm going to hope for the best and hope that that isn't the case, as I was told it probably ate away at the whole system. They told me the system still holds a seal (for 40 minutes anyway). They estimated ~900 bucks to fix it, so I said I'd do it myself.

Here is what I WANT to do, I need to know if I'm on the right track though.

I want to replace the receiver/drier, and the h block. I would first evacuate the system, flush it, then evac it again (to get the flush out) Then replace the h block, and drier. then I want to put in either 134a or DURACOOL, which i've heard a few good things about. What is my best option? if I go 134a, do I need some sort of orifice tube added, or can I run the system as is? What else do I need to do?

You will def need a new accum/drier. Also the o-rings should all be replaced with 134 compatible ones( usually blue or green). The condenser is probably ok I had mine tested for free at a local radiator shop. The expansion valve usually needs replacing after it has been sitting. It is hard to test the compressor until you charge the system and run guages on it. I am only speaking from my own experience with my 87'. You will need to put cvacuum on it before you charge it. Hope that helps

If it held a vacuum for 40 minutes how could the tech tell the expansion valve was no good?(I am no master at A/C just seems strange hopefully someone that knows will chime in) It makes sense to change the dryer when ever you "open up" the system. As for a condensor, R-134 works alot better with a parralel flow condensor but it will work with thetube and fin condensor you have on there now. I wish I never went to R-134 myself, but that is another story. The expansion valve, dryer, and a parralel flow condensor shouldnt run you more than $200, as far as a flush, Read up on the right way to do it, You dont want to be putting good parts in harms way. after flush and install go get a deep vacuum pulled and put in your R-134. or have them do it. You can find some good prices at www.ackits.com
Good Luck

i mixed r-12 and r-134a and it is cold. the jeep was sitting for 6 months. so i started her up and put the A/C on just to see if it still worked.(i thought not) it came on and was freezing. so for me it worked with out a hitch. but if you got a leak then you got to vacuum it out anyway so it will clear any r-12.

I just converted my 92 xj from r12 to r134 and it was a learning experience. I first took it to a shop and had the system evacuated of the r12. Then I went to Advance Auto Parts and bought a r134 conversion kit. It has the new fittings which just screw on over the old shrader valves. B U T!!! I kept NOT being able to put in the new freon??? Soooo??? I took it back to the shop which had evacuated it for me and asked them if I had done something wrong. They told me when I had them evacuate it the first time that the system was in good shape cause it would hold a vacuumn. So anyway when I went back the second time the mechanic asked me, well did you open the valves at the end of the lines behind the compressor? I said I did not know anything about any stinkin valves??? Then he showed me where the high press and low press line connects to the back of the compressor, at the end of the lines there are two black caps which need to be removed and then it exposes a stem which is like a needle valve. Annnndddd you have to open the valve to admit the freon. $130.00 later I am a little more educated???
I hope things go well for you!!!

Swabby

I converted my 90XJ from R12 to R134. I only replaced the dryer and the o-rings.

Good luck.

I bought the 30$ conversion kit that is made to convert the R12 system Without any need to evacuate, to 134a. Worked and still works Great! this is on a 1990.....

The conversion kit comes with a can of formula that converts the exsisting oil/blend of 12 in the system to 134a.

What is the difference between r12 and r134a? Why is it better?

less ozone depleating issues and thats about it. You really cant find R12 to the general public anymore so theres no choice..

First, have a shop suck out any existing R-12. It sounds like the system held vacuum for 40 minutes, so this has probably been done already.

Then cange the drier and expansion valve, then install the R-134 conversion fittings. Have the shop vacuum the system down again and charge it with the proper amount of R-134, and some dye in case there is a leak. You should be good to go after that.

On my 92 I bought a kit for Walmart. And put it in. it is working great. Mine had a vacuum on it so I put the kit in and the compressor came on and it get nice and cold in it.

I replaced the expansion valve and drier, and charged it up with 134a (after probably tearing a hole the size of nebraska in the ozone due to those valve stem things) And the system cools, though not amazingly well or anything. Much better than nothing, but I didnt have the system evacuated AFTER I put the drier and expansion valve and put the system back together, should I have?

amart565 said:

I replaced the expansion valve and drier, and charged it up with 134a (after probably tearing a hole the size of nebraska in the ozone due to those valve stem things) And the system cools, though not amazingly well or anything. Much better than nothing, but I didnt have the system evacuated AFTER I put the drier and expansion valve and put the system back together, should I have?

Click to expand...

Yes you need to have a vacuum pulled on it for like 30 minutes and get down to 30hg. The A/C system needs to charge into a vacuum in order to have enough gas and to run properly. The other advantage of vacuum is you take all the excess moisture out of the system other wise that dryer you just put in is half way to its death now. Go get it vacuumned and then filled properly with the correct amount of R-134
Goood Luck

Refrigerant 101... R-134 is similar to R-12 in that they operate in similar temp/pressure ranges...we won't go into WHY R-12 got banned, thats a different tale.. Anyways, converting over...the oil used for R-12 is a mineral oil...R-12 having been originally developed as a solvent, mixes with the oil very well...the oil is in the system to lubricate the compressor parts and the needle in the expansion valve....otherwise it is a nuisance that slows heat transfer. At any rate the oil must circulate through the system. The transportation method here is irrelevant...R-134a does not mix with mineral oil. Because of that fact, oil will trap in the evaporator and lines..this leads to liquid slug (A/C hydrolock) or the compressor failing from oil starvation.

The PAG "oil" that will mix with R-134a is a very poor lubricant compared to mineral oil..it is also highly hygroscopic..the oil will break down into acidic components when exposed to moisture and oxygen..never leave the system open to atmosphere..driers remove moisture and acid..they should be replaced whenever the system is opened..Evacuate for as long as possible..overnight is best. As a note...it is not a wise bet to buy used components from a R-134a system...the residual oil may well have acidified and corroded or rusted the parts.

Mixing gasses...it has been done to death...the remaining R-12 serves as the oil transport...it isn't efficient...and if it was done beause it was low..there is most likely air and moisture in there already.

MudDawg said:

Refrigerant 101... R-134 is similar to R-12 in that they operate in similar temp/pressure ranges...we won't go into WHY R-12 got banned, thats a different tale.. Anyways, converting over...the oil used for R-12 is a mineral oil...R-12 having been originally developed as a solvent, mixes with the oil very well...the oil is in the system to lubricate the compressor parts and the needle in the expansion valve....otherwise it is a nuisance that slows heat transfer. At any rate the oil must circulate through the system. The transportation method here is irrelevant...R-134a does not mix with mineral oil. Because of that fact, oil will trap in the evaporator and lines..this leads to liquid slug (A/C hydrolock) or the compressor failing from oil starvation.

The PAG "oil" that will mix with R-134a is a very poor lubricant compared to mineral oil..it is also highly hygroscopic..the oil will break down into acidic components when exposed to moisture and oxygen..never leave the system open to atmosphere..driers remove moisture and acid..they should be replaced whenever the system is opened..Evacuate for as long as possible..overnight is best. As a note...it is not a wise bet to buy used components from a R-134a system...the residual oil may well have acidified and corroded or rusted the parts.

Mixing gasses...it has been done to death...the remaining R-12 serves as the oil transport...it isn't efficient...and if it was done beause it was low..there is most likely air and moisture in there already.

Click to expand...

Bla.. bla.. bla.. Yada... yada... yada..

If you have a R12 system and need to charge it, just get the conversion kit from walmart, Autozone, pep boys ect. Screw on the connector and fill with cans of included stuff (must be magical?) and then use it at will....

Thats what I did and it has worked flawlessly for abotu 6-7 months and used alot lately...

The biggest difference between R-12 and R134 is the cost. If you are licensed you can still get R-12 in 30 lb bottles at a cost of $1000, way more than R-134.

The difference between a uninformative post:

ROBERTK said:

Bla.. bla.. bla.. Yada... yada... yada..

If you have a R12 system and need to charge it, just get the conversion kit from walmart, Autozone, pep boys ect. Screw on the connector and fill with cans of included stuff (must be magical?) and then use it at will....

Thats what I did and it has worked flawlessly for abotu 6-7 months and used alot lately...

Click to expand...

and a informative post:

MudDawg said:

Refrigerant 101... R-134 is similar to R-12 in that they operate in similar temp/pressure ranges...we won't go into WHY R-12 got banned, thats a different tale.. Anyways, converting over...the oil used for R-12 is a mineral oil...R-12 having been originally developed as a solvent, mixes with the oil very well...the oil is in the system to lubricate the compressor parts and the needle in the expansion valve....otherwise it is a nuisance that slows heat transfer. At any rate the oil must circulate through the system. The transportation method here is irrelevant...R-134a does not mix with mineral oil. Because of that fact, oil will trap in the evaporator and lines..this leads to liquid slug (A/C hydrolock) or the compressor failing from oil starvation.

The PAG "oil" that will mix with R-134a is a very poor lubricant compared to mineral oil..it is also highly hygroscopic..the oil will break down into acidic components when exposed to moisture and oxygen..never leave the system open to atmosphere..driers remove moisture and acid..they should be replaced whenever the system is opened..Evacuate for as long as possible..overnight is best. As a note...it is not a wise bet to buy used components from a R-134a system...the residual oil may well have acidified and corroded or rusted the parts.

Mixing gasses...it has been done to death...the remaining R-12 serves as the oil transport...it isn't efficient...and if it was done beause it was low..there is most likely air and moisture in there already.

Click to expand...

There is a difference between "works" and a proper repair."works" is ok if it is YOUR vehicle.....Oh and the "magical ingredient" is Heptane and Isobutane.

MudDawg said:

There is a difference between "works" and a proper repair."works" is ok if it is YOUR vehicle.....Oh and the "magical ingredient" is Heptane and Isobutane.

Click to expand...

Which incidentally, are illegal to use in some states because they are flammable (well R134 is too, but not nearly as bad).