Retrofit auto to R134-a

[Fishbusters]

I was wondering and figured i would ask you guys if anyone has done this and if so does it work as well as the "old" r-12 did in the system? I have to do something my 1990 surburban is no longer keeping things cool it still cools the air but not rearly enough. In the old day we would have added som r-12 but now you have to take it to a shop for that and they always tell folks you need this or that done even if you don't. My own mechanic who does not do AC told me once never trust an AC shop and i took a car to 2 and they gave me diffrent "needs repair" stories so I don't trust them.

 

[wvit100]

Re: Retrofit auto to R134-a

the new stuff, i think it's called c134, isn't as effecient as the old r-12. The systems in the new vehicles are larger to make up for this. you can install a new system that uses the c134 but it takes a whole new system, expensive. there are still places you can go to get the r-12 system recharged and fixed, expensive but not as expensive as a new system. I guess it just depends on how long your planning on keeping the vehicle and how much it's worth. I wouldn't want to spend $1000 on the cooling system of a vehicle that may break down next week. A suburban is a big truck to try and keep cool on a hot sunny day you may want to try and get the stock system working right.

 

[Bob_VT]

Re: Retrofit auto to R134-a

I have converted both systems in my 93 car and 84 truck (Ford's). I had both systems "vacuumed" by a garage and I took it from there.<br /><br />I got the retro-fit system added the can of "oil charge" and the proper amount of 134a to the system. Cool and no complaints so far and going on 3 years for both.<br /><br />Do a search on Google.com and you can find the specific amount of 134a required.<br /><br />Check to see if any parts have to be changed over in particular the a/c clutch. (my 93 needed a differant clutch which was far cheaper than a new compressor) The new fill adapters will come with the kit.<br /><br />Bob

 

[DJ]

Re: Retrofit auto to R134-a

Bob_VT, has it right. 134a is not quite as efficient as R12. Most R12 systems are large enough to still produce adequate cooling with 134a.<br /><br />Basically, it is the rubber parts from R12 that are not compatible with 134a. You will need to change all hoses (134a has smaller molecules and can migrate through R12 hoses) and you need to change the compressor oil to a PAG type.<br /><br />It is best to flush the system completely and then add the oil as the two oils are also not compatable.<br /><br />There are many kits available out there from OEM's and the aftermarket alike. Most include: hoses, instructions, seals, PAG oil and a different size orifice for orifice systems.<br /><br />I have found that older POA valve systems have trouble with 134a. It takes some adjusting to get the system just right so that it doesn't cycle too often or build excess compressor head pressures.

 

[hulteen]

Re: Retrofit auto to R134-a

I have done a few successful, and some not quite as sucessful retros to r-134a on personal vehicles, A good site to check out that has a wealth of info and different retro options is www.aircondition.com

 

[hulteen]

Re: Retrofit auto to R134-a

On a side not, unless you have $1000's of dollars in eqipment, and a lot of time to flush out the old r-12 oil, I would not recommend using PAG, it is the best choice and by far the most compatible oil with R-134a, but if even trace amounts of R-12, the old oil, or moisture contaminate it you can have a whole world of problems, OEM r-134a systems use PAG but I have found out the hard way that it is not DIY friendly, I recommend using ESTER oil. <br /><br />P.S. If I were a professional with $1000's worth of equipment and got paid by the hour I would dissagree with my own statement

 

[Fishbusters]

Re: Retrofit auto to R134-a

Well it seems to work fine for me so far. I hope it continues to be the same for as long as i own the truck.

 

[sjksjk]

Re: Retrofit auto to R134-a

There are drop in replacements for R-12 that do not require oil changes or Metering device changes. Although they do recommend changing to a POE(polyolester) oil it is not mandatory as with R-134a. I do not know the exact name of these drop ins, but if you call the local HVAC supply house they should be able to tell you. They probably won't sell to you if you do not have a certification to buy refrig., or if they are wholesale only but should be able to answer your questions. Stu

 

[GarageGuy42]

Re: Retrofit auto to R134-a

It would be my recomendation to stick with r-12 as long as you can. I've converted quite a few systems and the results are good in some and not others. Not all auto ac's are created equal. One reason is that the condensers in an r-12 systems is quite a bit smaller than r-134 and it needs the bigger condenser for better heat transfer,otherwise you will end up smoking a compresser. Even a new compressor has a hard time keeping up with the higher head pressures. If you do you will need a high pressure switch inline to cut the compressor off.<br />I would have it charged with r-12 and have some injectable dye put in that you will be able to see with a blacklite. Freon sniffers are to unreliable. Usually only in a evaporato case. I have better results this way and do at the very least 8 ac jobs a day in the summer.

 

[hulteen]

Re: Retrofit auto to R134-a

unless you are certified they will only sell you refrigerants that have Zero Ozone Depleting Potential or ODP i.e. no HCFC's CFC's you can hypothetically and I throw this one in the category of do this only if you want to and I neither recommend or reject this, only urge caution you use a Hydrocarbon refrigerant, actually cools better than R-12 but several states have outlawed it because it as they are a 60/40 propane/isobutane blend and very flammable. and is only illegal on the Federal level if used to replace a 2nd Generation refrigerant, what you choose to do is up to you, but just throwing some info out there.