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A/C conversion on Early NSX?

27 December 2001
Dallas, TX
I have seen many 91's for sale that say that the A/C has "not been converted". Or, sometimes it will say that it has been converted to an "R-134".

I am assuming that R-134 is some sort of unit that uses a different coolant?

Is this good or bad? Should I look for ones that have been converted? Ones that have not? What are the differences?

Thanks to anyone who replies.
Oops. I revised my search on the forum archive and I pulled up this thread which is very helpful and pretty much answers my question.


Basically, it would appear that having the conversion is a good thing. However, if you don't have the conversion already done, wait until your current r12 unit needs repairs to have the system converted(make sure you update the compressor to it says).

I think I understand that. If anyone has any personal experience to add to this query, I would be grateful to view your experience.


R-134 is a newer type of freon that has replaced R-12 (I think R-134 was developed mainly for environmental reasons). Mark Basch is by far the expert on this. The modification is a few hundred dollars at most, so I would not let this "update" sway you either way in regard to a purchase decision.

One thing is that the R134 freon is cheaper then the R12 in todays market, so overall A/C work (recharge) will be slightly lower in cost, going forward, if you convert or get a car that has been converted. Again we are talking maybe $150 or so.

My understanding is that there also is a newer type of freon, (don't recall the name, but it has a 12 in it!)that can be used in non-converted systems that is also cost effective as of late, which could make the requirement to consider updating the system meaningless.

A good time to do any of this is if you are having A/C work done for other reasons.

My 1991 has perfect A/C operation, still has R-12, and is fine after 11 years (30K miles), if that puts it into perspective for you! The only other comment is that I am on the east coast, so A/C is used alot less by me, then perhaps by you.

Originally posted by Larry Bastanza:
My 1991 has perfect A/C operation, still has R-12, and is fine after 11 years (30K miles), if that puts it into perspective for you!

I have the same scenario as Larry (except my '91 has 114K miles). So far - no problems with the AC.

'91 Black/Black
Thanks for the response guys!

So it looks like I would not even need to do the conversion at this point. Very nice. And apparently even if I did decide to upgrade, it would be inexpensive and certainly not anything I should be concerned about when buying.

Larry, A/C is something we take very seriously down here hehe.