Cold AC How to make colder?

[Art Garcia]

Hi! I have an OEM Air conditioned in my 93 XJ. The air output it's not very coold, some 44ºF.

this temperature only works on days below 90ºF. I have the old R12 gas and is properly recharged some weeks ago, there is no leaks in the system.

Any Help is welcome more if before my travel to Arizona.

 

[5-90]

When I did the R134a retrofit, it felt like I was sitting in a Kelvinator with the Aircon cranked - the newer coolants are also much more efficient...

I've heard there's a newer coolant than the R134a, which is also R12 compatible. Can anyone shed some light on this?

5-90

 

[martin]

Art,

I looked in my book and it says the discharge air temp should be 35-41F for outside temps of 70-100F.

I have a suggestion, have you replaced the mechanical fan clutch lately? On my 88 XJ the electric fan is turned on when the compressor clutch is engaged but the designers were counting on a good mechanical fan.

My suggestion is go buy a new fan clutch for the mechanical fan and install it. I hear you should figure on 5 years of service if that much.

You may also want to examine the condensor, the thing in front of the radiator. Use a garden hose and wash off all the fins and make sure no leaves or other stuff is blocking the flow of air. I went to the car wash and used their wand once to do this to my AC Condensor.

Just so everyone knows you can not mix R-12 and R-134. You have to pull out all the old R-12, pull a vacuum then install the R-134, that ester oil they give you in the kit makes this possible.

If you look at replacement condensors, the one for XJs with R-134 is a different part number and talking to AC guys they tell me you need more condensor to get the same performance.

I do not know about a newer refrigerant than R-134. I have heard of some replacement refrigerants that use Butane or Propane. They work great until you have a leak. I would stay away refrigerant that contains a CxHx molecule because they all burn!!! The R-134 and R-12 do not burn if you are in an accident.

Martin

 

[5-90]

Did I not mention that they are incompatible? I may have missed that...

I didn't know about automotive Butane/Propane refrigerant systems - it makes sense from a purely mechanical point of view, and I've heard of portable refirgerators the run that way - just not air conditioning...

All I did for the R143a retrofit in my 87 was replace the receiver/drier, orifice tube, and the system seals. The condensor and evaporator remained OEMR, as well as the compressor (for $600, I kept that thing!) and everything was just ducky until the pressure hose (also original!) finally let go at the crimp - which froze the compressor as soon as the oil all blew out, and on the first really hot day that summer!

It is interesting to note that Halon is a close derivative of Freon, which is why it won't burn.

I'll have to dig around on that other coolant question - I'm sure I heard that somewhere a year or so ago, but can't remember where....)

5-90

 

[martin]

5-90 you are right you did not mention running R-134 or R-12, but thought I?d say you can not mix them in your AC system just incase someone reading the post was not aware of that factoid as CNN calls them.

You can thank the Montreal Protocol that said in 2000 all countries would stop using certain Ozone Depleting Compounds. The President at the time decided to push up the schedule to 1995 for the USA. Thanks to this Treaty R-12 and Halon are ?bad? and can not be manufactured after 2000.

I know there are big efforts to find a replacement for the Halon used in fire extinguishers. I hear a substitute may be found but field tests have to occur to prove out the new compound.

As for my since R-12 is still available I?ll continue to use it in my 88 XJ. Lucky for me my system takes 32 oz of R-12, in 89 they went to 40 oz or R-12. Even at $40/lb I can keep topping off a leak. IF I ever change the heater core I will install a new evaporator, along with hoses and O-rings. If I get to that stage then I?ll do the math and figure out to convert or stay with R-12.

I still think Art has a mechanic fan with a bad fan clutch.

Martin

 

[Art Garcia]

Thanks for your answers 5-90 & Martin!

I replaced the fan clutch, some monts ago, I live in Mexico, here we can still using R12, Last year I ask to my mechanic about make a retrofit to R134a and he told me it's not a good idea because my sistem is not to going to cold very well.

He explain me he also need to replace the expansion valve and place a new and larger evaporator for make a more reliable retrofit and that changes are going to be very costly.

Then he make a complete repait to my unit ( I filled with R12 without purging the R12 ) and after all the major repair the air conditioned don't work very well.

Any suggestions?

Thanks

 

[5-90]

I did find the conversion workable, and I was able to do most of the work (replacing parts!) myself. I did the conversion in three steps -

1) Take XJ to local AC shop (same place I get my radiators) and have the "purge" the system. I told them it would not be necessary to pull a vaccum on it, as I was going to open everything up anyhow.

2) Replace parts. Reciever/Drier, orifice tube, LPCO switch (it was bad anyhow,) and seals. NOTE - I got the Everco kit thinking they'd have it all sorted, and everything I had was O-rings. I wound up pulling all the orings and taking them in to be matched. Check you system first - if it looks like flare junctions, they are probably orings. Make sure to use aircon orings, as everything else will come apart on you!

3) Return to aircon shop, report work performed, and let them purge and charge system.

I think the total cost, with me doing most of the labour, came to about $300 - but I get good prices on parts and I get a break from the very few shops that I use, because I send them as much business as I can. I could expect 2-3x that if I paid them.

The key is replacing anything that will not fluch out completely - the two lubricants are incompatible (it's not the refrigerant, it's the oils) and will cause system failure if they are not purged completely. When I talked to my shop before I got started, they told me that replacing the orings would not be strictly necessary, as they don't soak up enough oil to be a problem, but I changed them anyhow. The liners of the hoses are basically non-porous, so that's not a problem. You will run into problems if you don't change the orifice tube and the reciever/drier, as they do not flush all the way. The evaporator and condenser will flush completely, and they will work well with the R134a in my experience. If you are willing to put the time in to do the retrofit correctly, it's worth the time (especially if Freon goes the way down there that it did up here!)

I still need to dig for a newer coolant, if it exists. I suppose I could be imagining things... If I find anything out, I'll be sure to pass it along.

Also, make sure to clean the surfaces of the evaporator (near the heater core) and the condenser (especially - in front of the radiator) as those surfaces being dirty will quickly degrade the efficiency of the system!

Where in Mexico are you, anyhow? Just wondering...

5-90

 

[Art Garcia]

5-90 Thanks for your detailed explication.

I´m from Monterrey Mexico 150 miles south of Laredo Tx. Do you know where is Monterrey?

I live in the sorrounding area in the city of Santa Catarina, N.L. if you came to Mexico for any reason, please let me know for welcoming properly

 

[5-90]

That does sound familiar, I could probably find it on a map without any trouble. If I come down that way, I'll dispatch a warning.

Perhaps I should brush up on my Spanish...

5-90

 

[Judd W. VA]

Isn't R12 still mfg in Mexico??

Thought R12 was still available in Mexico..... Is the best to use if possible, but there are other compatible refrigs out there- like DuPont Suva 409 used in the commercial/home refrig business. Believe there are other names used in the auto industry. R134A is not as efficient and has some lesser characteristics. Stay with R12 i'd advize.

 

[Art Garcia]

The Mechanic think he found the problem. The evaporator installed it's a Chrysler OEM but it's diferent than the evaporator in the service manual.

I'm going to replace the kind of evaporator by the same appears in the service manual.

Anybody know a better evaporator than OEM?

 

[yellowxj]

Freeze-12 is an available alternative to R-12. About 8 dollars a can I believe. Its mostly R-134, some R-22(?), and about 4% butane. Not enough to be a fire hazard but enough to make the Freeze-12 super cool.

Of course I'm cheap though...We have seen r12 systems "bumped up" with a bit of 134 before and seen them work well for a long time. Some compressors are not really compatable with the new oil installed with the conversion to 134 and self destruct soon after. Make sure your compressor is compatable with 134 and use the appropriate oil in the system.

My 88 xj was a r12 system that was low enough that it wouldnt work when I got it. Everything appeared to be in good order so I had the system evacuated and added a 2 oz. oil charge and filled it with 134. Got it down to 40 deg.

2 cent.

 

[RichP]

Check between the rad and evap, alot of crud gets stuck in there, lays at the bottom till you start the engine and it draws a suction pulling all the crud laying in the bottom. I try to do it once a year, gets rid of old bugs, leaves, etc. I also sit in front of the rad with toothpics and pipe cleaners and clean out the fins from exploding bugs and such. It makes a difference.

 

[Bronco]

Warning
Do not use high pressure to clean you radiator it can fold over all the little fines, and you will get to spend hours straitening them with a tooth pick or get a new one. I mean aaaaaah that’s what I hear…