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Discussion Starter #1
My 1991 SE needs some AC assistance. I have read that older R12 systems can be re-charged with RS-24....has anyone here done that? Or has anyone done the conversion to R134a, and what did that cost (roughly)? TIA.
 

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Wingless Wonder
1988 Esprit Turbo
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No experience with RS-24, but I see that it contains Butane... o_O

Many have converted to R134, but be warned, the cooling effectiveness noticeably isn't as great. Some have had issues with leaking hoses after that.

Why not just keep using R12? You can find it for sale on EBay. I'm still using it.
 

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Discussion Starter #3
That's what I've always heard about R134a conversions, and the Lotus doesn't need diminished AC.

I did not think many shops would recharge with R12...have you had them do it, or did you do it yourself? How difficult was it? I don't have the tools typically required for AC repair...

Thanks!
 

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Lawdog,

I did a bunch of research on this issue prior to getting my car simply because I didn’t know exactly what shape the AC was in. Luckily mine blows strong and icy cold so I’m good, but if you do a search on “AC Recharge” in the Esprit forum you’ll find a ton of good info. The general consensus is sticking with R12 is the way to go, unless your system is in need of a complete rebuilt. In that case you could do the 134a conversion but expect the system not to blow as cold.

Some guys locate the charge ports under the car, accomplished more easily if you have access to a lift. Seems like most guys use right angle adapters from above the engine bay on the ports directly on the back of the compressor. Either way, get your can of R12 and follow the directions. Shouldn’t be too hard to recharge the system. I’ve done them on several of my older vehicles. Keep in mind if your system has a leak you’ll be losing all that new R12 along with compressor oil, which eventually leads to compressor failure. If you have these concerns, best to take it to a professional shop who can inject die into the system to locate any leaks prior to recharging.

Good luck!
Eric
 

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Discussion Starter #5
Thanks, Eric; I did see some of those R12 recharge threads. I just talked to my local British Car Club mechanic, and he has R12/can do the recharge with the proper equipment and check the system for leaks, etc. It looks like the SE has recharge ports on the back of the compressor, so, hopefully, it shouldn't be too difficult. I was going to have him give the car a once-over anyway, so looks like "problem" solved. Thanks to all who responded.
 

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I changed my 89 Esprit (RIP) to R134. It went fine. I changed it out when I replaced the leaking compressor and leaking little U piece under the dash. I used a new Sanden compressor specifically for R134 with the right oil, etc. Just charged it up with the R134 and it worked without problems. I had an ice cold knee. I've done other vehicles as well without changing the compressor.
 

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According to the MSDS sheet it DOES contain Butane, a flammable gas. You are not alowed to use a flammable gas in a mobile refrigeration system as in a car. Try to stay with R-12 as long as you can. As others have posted, R-134 will be less efficeint and won't provide the same cooling capacity as R-12. To change to -134 you must also flush out ALL of the oil or you will have problems of compatibility with the oil for -134 resulting in "Black Death" of your system. Bottom line, stay with the R-12
David Teitelbaum
 

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Discussion Starter #8
Yes, I'm staying with R12. Was worried about who locally could do it, but that has been resolved.

I don't think anyone in the US is/can do the RS-24...almost all the sites/shops are in Canada, the UK, etc. This article from Hagerty doesn't even mention it among the alternatives.

 

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I am in process with R12 to R134a on a older vehicle. At best it is difficult. I am having to take compressor out, flush old non R134a compatable oil out and then replace with Ester oil. I have to replace dryer, Replace all gaskets I can get to. Try to draw and keep a vacuum, then recharge with Industrial grade 134a. R134a does not cool as well.

I may or may not replace oil in condenser, depending on how I feel at the time of disassembly. You can have up to 50% of old lubrication oil in the system, but of course that isn't ideal... This may work for awhile or the system may flip me the bird for real. My scenario has no R12 in the system at all so I don't have to recover anything. I am replacing one hose, and it's a tshirt type affair if successful. there was a fire.

I will be drawing the line if the Evaporator in the dash goes south. Your actually supposed to replace the R12 one for one designed for R134a, but will still work. I am not retired yet and do not have the time nor fortitude to go the distance on the AC if I have to tear out the dash to replace any plumbing in there.
 

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I'm replacing the AC in FrankEnSPRIT with an R134 system. The engine I have already has an R134 compressor, and replacement hoses and dryers are pretty easy to get. The chargecool/condenser unit from Lotus is sized for R134. The hardest part of the whole conversion is replacing the effing expansion valve.
 

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I don't think you need to replace the expansion valve. I did when I converted mine, but only because it was suspect when I ordered parts. The valve I got was identical to the one that was in there. It opens/closes based on thermals, not any freon type specific thing.
 

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Oh sure - now you tell me.
 

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When converting you really should replace the TEX (Thermostatic eXpansion) valve according to the refrigerant you are going to use. The pressures and temperatues vary and to get the most out of the system you really do need to use the correct valve for the refrigerant in the system. The dryer should be replaced and each component should be flushed to get as much of the old oil out as possible. The hoses should be replaced with "barrier" type and every "O" ring seal should be replaced. The compressor does not have to be replaced but it can't hurt. Because the TEX valve is not adjustable so you can make it work with different refrigerants, it should be changed. You have to remove it anyway to change the "O" ring seals. You are also supposed to change the service ports and install a new label stating that the system was converted with the type of refrigerant and the amount. When changing to -134 you are supposed to reduce the amount of refrigerant by 10% because of the higher pressures. Because -134 has a lower molecular weight it has less mass to transfer the heat energy. Between that and the higher pressures, you lose around 10% of your cooling capacity. Rule-of-thumb, you get 12,000 BTU (1 ton) of cooling per pound of refrigerant. Less refrigerant = less cooling. You won't notice it till you need it and In Socal you need all the cooling you can get. The Lotus Esprit is like a little greenhouse with all of the glass, especially with the sloped windscreen and if you also have the glass roof. There is no good reason to convert as long as you can still get R-12. No law requires you to convert if the system was originally built to use it.
David Teitelbaum
 

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I'm a mechanic, with 25 years experience, in Arizona so we have many older cars, and hot weather. I've done many 134a recharges on r12 systems with just the adapters on the charge ports, always with decent to good results. I'd swear the early 90s 4runners I do are colder than r12 with about 18 Oz of r134a, some odd reason I've done a lot of 4runners in the last ten years. You can get harbor freight gauges and they're decent for the price, their vacuum pump isn't bad either, but the one I used only hit 27 or so inches of mercury. When you recharge it's typically a little less 134 than it would take r12. High side should be at least double ambient temperature and low no higher than half if not lower. I typically see 250 plus and around 30 for around 100 degrees outside. I've also done the full swaps, compressor, receiver dryer, etc and partial swaps, no compressor etc, but I've never noticed a quality difference in the end, between full swaps, partial, or just charge adapters. I will say most of the systems I've done were late 80 to early 90s and I have heard the older you get the worse the outcome and increase in part failure compatibility issues.
If you're ever in the area I'll charge it for cost in r134a and some beer, as long as it's posible to get at the charge ports without being elastic girl, or guy, was there a guy, lol. With that the adapters are kind if long and can be a pain in that area, plus the connector going on top of it for charging.
 

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I'm a mechanic, with 25 years experience, in Arizona so we have many older cars, and hot weather. I've done many 134a recharges on r12 systems with just the adapters on the charge ports, always with decent to good results. .......... etc
Thanks for the info, thinking of doing the conversion this year (finally) and have been hisitant to do mostly due to fear of destroying the system.
 

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Dont forget these were not my cars, Ive never owned a converted system car. It could be that every singlee one had problems one year later, but I never heard or was told about it, I doubt that happened. CBD auto is just me and thats the past 5 years, before that any shop I worked at was smaller but had a sales person so I didnt necessarily talk to the customer. I have defiantly heard that oil doesnt mix, etc, but never seen proof. Also I think it could be that expansion valve systems react much better to the change than orifice tube systems, I believe all the 4runner systems are expansion valve, hence the positive outcome.
On a side note it is very dry in AZ, so I think we have an easy time with ac and moisture. Its very bad to have water in the system, one of the things putting the system into a vacuum does is boil off the water. So I think the cheaper vacuum pumps work better here. I always try to wait till last to install the receiver dryer and keep the caps on it till then, or remove it first and cap it right away, etc. I reuse them often here but would be more inclined to replace in humid areas. They should always be replaced if there is metal in the oil or lines (compressor detonated) as they are a filter.
 

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I have seen systems that had what is commonly known as "Black Death", contamination because of incompatible oil and moisture. The insides are coated in a slimy black residue. The EPA has very strict rules but often shops take short cuts and do not do the complete job. A complete job takes more time and parts so it can get expensive so there is an incentive to do a "quickie", especially when the customer says do it cheap or I will take it to another shop. Some shops in the Southwest and Mexico would fill a car up with Butane or Propane. It makes a great refrigerant if you don't care that it could explode! It got so bad that dealers have bought testers so they can verify what's in the system before they would take a car in trade. A customer would not realize their system is 10% less till they try to cool it on a REALLY hot day. That's when you actually need every bit of the capacity but it isn't there. It will still feel cold compared to the outside air but it will take a lot longer to achieve the set temp inside the cabin. If you really feel the need to convert, there is a class of refrigerants called "Blended Mixtures" that are "Drop In" replacements. R-414a is one of them. While they are direct replacements they do have some disadvantages. You can only "top off" once or twice because the blend will change so you must remove and replace the entire charge to maintain the correct balance of the mixture. They are less efficient so you do lose some capacity. The big advantage is you do not have to flush the system or change anything except the label. The best advice is to try to stay with R-12 for as long as you can.
David Teitelbaum
 

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Discussion Starter #18
My '91 SE at shop now, say hasty r134a swap was attempted previously...compressor leak...replacement unit is $611, replacement drier $127, new TEX valve for correct R134a conversion. About $600 in labor, and no more R12. Not what I was hoping for, but that's life.
 

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Compressor about $215 (Buy Auto Parts)
Dryer about $20 (All Season)
TEX about $40 (just guessing)
Seal kit about $20 (another guess)
Refrigerant, flush, oil, shop supplies, figure $100 (estimate)
Labor should be about 6 hours. If you stay with R-12 the labor is a little less, no TEX valve, the refrigerant a little bit more. Works out to be about a wash. Could be more time and parts depending on what is leaking if they actually fix all of the leaks. They are hitting you full list +++ on the parts and about $100 an hour for labor. Make sure you get a guarantee for this price and it should be more than 1 season.
David Teitelbaum
 

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Discussion Starter #20
Thanks, David. It seemed a little high, but there are not many options here in Charleston, SC, and this shop is reputable/offers a 2yr/24,000 mile warranty on their work. AC parts always seem to have a 100% markup or worse if you go through the service provider. I entered a service note with the price ranges I found on BAP (thanks for that link), and asked for whatever break/discount he could do. Since this is my first service with them, hopefully they will want to shear the sheep a few times rather than skin it once!
 
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