shum8

After owning my 88 XJ for one year I was under the impression that my compressor was shot. So while talking to a co-worker last night he informs me that he new AC stuff. With a simple paper he diagnosed my problem. He bypassed the low psi switch amd wow. It started working. It actually had enough freon to blow some cool air. And my elec fan worked fine also. So I started researching R12/134A stuff. I came to no conclusions. Too many opinions for me to form my own. Whats the deal with mineral oil vs synthetic oil? Can u buy just 134A without oil? My friend told me to get an adapter. And just put freon in it. He said that it would take 80% of what it called for. Thoughts/opinions please

autosurgeon

Mixing r12 and r134a illegal and will wipe out the compressor. You see r134a will not carry the mineral oil through the system and thus the compressor will either end up with all the oil or not enough and lock up.

You need to have the r12 removed by a shop with a recycling machine.

Then retrofit the system.

The best option is to replace the accumulator and flush the system with ac flush and compressed air. While you are doing that the compressor should be off the vehicle and draining via the oil drain plug.

Replace all o-rings and you really should install a r134a specific orafic tube if available.

Ester oil is compatible with mineral oil so it should be used as there will be trace amounts of mineral oil left in the compressor.

You will need a retrofit chart to know how much oil and refrigerant you will need.

Also you will need a vacuum pump to suck the system down and hold it at a min of 25 inches of vacuum for 6 hours. This will boil out any moisture and remove all the air.


This is not a complete instructional list and if you do not have the proper tools you should not attempt this on your own.

shum8

Ok Thanks. I have a friend at the vocational school and they start Monday. May be a good project for them. Its not my daily driver and I can do without the vehicle for a spell. Thanks again

Pelican

I agree wholeheartedly with having a vocational school or anyone else who knows auto A/C and has proper equipment take on this project.

However, it is quite possible to convert the system to 134a with only an initial evacuation (by a professional or someone who knows what they are doing) and changing out the fittings on the compressor, adding oil and 134a refrigerant.

Just saying it is quite possible to do successfully, not suggesting you do it nor guaranteeing it would be successful. I've done two vehicles (including '85 XJ) this way that worked great.

autosurgeon

Yes it can be done with a little research and the right tools. But will it last and be reliable? That depends on it being done right. And simply adding oil and swapping fittings is not a proper retrofit. Even though such kits are sold in parts stores they are not technically even legal.

shum8

I will take all this into consideration. Let me ask this. Is it hurting anything at all to leave it like it is. Meaning it has low psi and the compressor is not kicking on. Ive had it one year and no telling how long its been in its current condition. Since summer is almost over Id just assume spend money on something else.

autosurgeon

No it will not hurt it.

shum8

Thanks sir. You have been a big help.

Pelican

The kits are sold everywhere and have been openly for sale for a lot of years, essentially since R12 became unavailable which is when I did my '85. Exactly why are they illegal and why have I never heard that before and why isn't someone after them?

My '85 swap lasted about 5 years as I recall offhand but I was really not taking good care of it at the time in the sense of servicing the A/C.

I didn't have to do any research other than reading the instructions that came with the kit. And it took no special tools. At the time, the pro shops would evacuate the system for free in exchange for the residual r12.

I have had my '93 for 9 years and I know it was changed over to 134a by a non-professional. I can not swear exactly what was done but I would be surprised if it included a full retrofit. I add about half a can of 134a every year and a half and it cools quite adequately in the heat and humidity of SE Texas. The acid test: my wife doesn't complain.

To the OP, I don't think anything bad will happen if you let it go another year but I will defer to the pros fo a final answer.

autosurgeon

Welcome...and if you decide to tackle it yourself there are some very good videos on YouTube and the vacuum pump and gauges can be had inexpensively at Harbor Freight. Just remember to have it evacuated by a shop the legal way first.

autosurgeon

The kits are legal to sell as they are not forcing you to do anything and who is to say what you will do with them. They are not a complete retrofit as detailed by the EPA and thus if simply installed and charged they do not constitute a legal retrofit by themselves. A legal retrofit consists of the following.

Receiver dryer replaced, orifice tube replaced if available, all old oil drained and system flushed to remove residue, all o-rings replaced with r134a compatible o-rings, correct oil charge of either ester oil or PAG oil added to system, system pulled to minimum 25 inches of vacuum for 6 hours, system able to hold vacuum after pump shutdown for minimum of 3 hours, finally correct charge of r134a added and performance test completed. Vehicle on a day with an ambient temperature of 70f can output 45f air from center vent at 2000rmp after running for 10 min with Windows open.

That is a complete retrofit... Also a good idea to replace the front seal on the compressor or the entire compressor if there is any sign of leakage there prior to the retrofit.

Your vehicle has slow leaks most likely from tired o-rings that are not designed for the refrigerant you are subjecting them too. Sadly r134a is just as bad for the environment as r12 was just in a different way. So leaks are a bad thing.

autosurgeon

Soon we will be talking retrofit again as there is another new wonder refrigerant on the horizon for automobiles.

Pelican

I somehow feel that I will miss the next retrofit, but who knows....

It is tempting to get into the pollution aspect but this isn't my thread. In any event I will never argue with doing something right, just with the fact that not everyone has the funds/time/contacts/etc. to do every project "right" at a given time.

With that, it is getting very late and I leave this project in autosurgeons good hands.

I

shum8

I will only be putting a minimal amount of money in this AC system. That is why I said I was going to let kids at vocational school do the work. But I do hate to not atleast try since everything seems to be in working order. However when it does crap out I will not be fixing it. Has anyone done away with compressor and freed up some room under hood? Can u get a shorter belt and make it work?

autosurgeon

They make an idler pulley that bolts on in place of the compressor. Or you could use it to make an onboard air system.