R-12 to R-134 - Page 2 - LotusTalk - The Lotus Cars Community
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post #21 of 28 (permalink) Old 08-22-2019, 12:26 PM
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Can you email me the information? [email protected]
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post #22 of 28 (permalink) Old 08-22-2019, 01:50 PM
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The upshot of this conversation seems to be do not change your R12 system. Any kind of change is complicated and some of them are REALLY complicated. Who in their right mind wants to pull the AC hoses in an Esprit unless you happen to have the left side of the interior gutted. In fact I would not want to have a shop do any of that kind of work. If I ever got into a situation where I had to replace the hoses I'd just have the AC shop drain the system, give me the hoses and I'll put them in, then they can do the rest, swage the fittings, etc. So what I have done is just stuck with R12 - my local shop says it added about 30% to my last service (they detected and fixed a leak, flushed and refilled the system). It blows nice and cold even in Florida for the most part. Once it gets up above 95F and high humidity (which is of course all the time) the system struggles somewhat, but it's not big enough to expect it to handle those conditions - it never was designed for those conditions. It is especially difficult if the car has been sitting outside and gotten a lot of sun exposure. If its been in the shade or garaged even in 90+ heat the system will do OK. My understanding is that R12 is no longer legally produced, but the existing stocks are legal provided the service shop is licensed, etc. And there seems to be a fair amount of R12 still out there - and it can be reclaimed. So me, I'll remain an R12 guy.
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Tom Mieczkowski
1989 Esprit Turbo
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post #23 of 28 (permalink) Old 08-22-2019, 07:50 PM
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post #24 of 28 (permalink) Old 08-23-2019, 01:08 AM
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Originally Posted by Kevininga View Post
Can you email me the information? [email protected]
Why bump an 8+ year-old thread instead of starting a new one? .

You didn't quote the forum member (like I did here) that you wanted the information from, or mentioned the forum member's alias (i.e. @oldmansan ), so you haven't made it clear as to who you're addressing, and unless they're reading every post/thread on the forum, you're far less likely to get a response from the intended forum member, especially given the 8+ year time gap.

You could have PM'd the forum member with the question, which likely would have provided a direct response from the intended addressee, if they're still around. Just a thought (or four).


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post #25 of 28 (permalink) Old 08-23-2019, 06:21 AM
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Originally Posted by karmavore View Post
Has anyone done a proper A/C refrigerant conversion? If so, did you use OEM parts? How'd the job go? Does it cool correctly?
According to documentation I have seen, my S4s came from the factory with R12 but somewhere along the line it was converted to R134a.

It looks like they used factory parts.

Cooling was marginal in Pennsylvania though currently I have the common hose/connection leak up front that some S4s have gotten and will need repaired.

'95 S4s ...SHF63000
'79 JPs #040
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post #26 of 28 (permalink) Old 08-23-2019, 06:25 AM
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Originally Posted by jtrealty View Post
Even if you do everything "by the book" and convert an R-12 system to -134 you will lose about 10% of the cooling capacity. The components were not designed to use -134 and are not sized ...
Can you explain how sizing works? What is typically changed to increase "sizing" capabilty--compressor?

'95 S4s ...SHF63000
'79 JPs #040

Last edited by flowersrj; 08-23-2019 at 06:26 AM. Reason: signature chnage
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post #27 of 28 (permalink) Old 08-23-2019, 09:42 AM
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The differences between an R-134 system and an older R-12 system;
The condenser coil is bigger
The pressures are higher
You need at least 10% more capacity to hold more refrigerant to achieve the same cooling capacity (R-134 has less mass so to get the same amount of cooling you need more -134 to equal the cooling capacity of -12)
Barrier type hoses
Different oil
Different service port fittings
Different expansion valve (or adjusted to operate with -134 if adjustable)
Different service label indicating the amount and type of refrigerant

To convert, the system should be flushed with R-11 and the oil, dryer, service label and service fittings changed along with the refrigerant at a minimum. If your system is working with R-12 and is relatively leak-tight, I see no good reason to convert. Even if you have to add 1/2 # of R-12 once a year it is cheaper than converting (you should not have to add that much if you fix all of the leaks). Just converting doesn't fix leaks and you would still have to add -134. The difference in keeping -12 to -134 is minor.
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post #28 of 28 (permalink) Old 08-27-2019, 06:07 PM
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Our R12 equipped system in the Wingless Wonder froze my kneecap on the LOG39 trip, 4 hour drive each way.

The foam seals in our HVAC system are deteriorating, though, so the vents kinda whistle when they are closed....

Atwell Haines
'88 Esprit
Succasunna, NJ USA

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