1991 z32 n/a r134a conversion - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z
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post #1 of 4 (permalink) Old 04-13-2019, 02:12 AM Thread Starter
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1991 z32 n/a r134a conversion

Hey guys,
I’m moving from Oregon to Arizona in a few weeks so I figured it’d be a good time to recharge my AC, since it doesn’t blow cold anyways.
I buy the r134a stuff, come to find out it’s an r12. I’ve never recharged AC before let alone convert it.
I read somewhere that I need to replace the accumulator and all the lines and other sites say that I don’t.
If I discharge the system myself, put the r134a fittings on and fill it, will I be fine? Or do I really have to go through all the trouble replacing everything? What’s the most efficient way to go about it?


Just a newbie with a 77 280z and 87 z31.
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post #2 of 4 (permalink) Old 04-13-2019, 10:48 AM
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Is there any R12 left in the system, if so it will need to be evacuated to do a conversion. Take it to a shop for this.

Below is the things a shop could do or you could do once the R-12 has been removed.

2st thing you should do is a vacuum test to see if it will hold a vacuum, (or a pressure test and see if it will hold pressurized nitrogen gas). No reason to start adding Freon if you have a leak. If its been out of commission for a long time and if its not under pressure, then there is a good chance that corrosion has setup and you will have to replace most of the parts anyway.

So get a good vacuum pump or nitrogen and test to see if there are any leaks.

See if you can turn the compressor by hand (not the pulley but the inside part of the clutch).

If all that test out ok, then you will need to at a min flush the system and replace the accum/drier (which ever it uses).
Barrier hoses should be installed to replace the old rubber hoses if you intend to use R134a
The compressor oil should be dumped and replaced, most places recommend ester oil on conversions vs PAG that is normal for use with 134a, this is due to ester being ok to mix with any remaining mineral oils left in the system.

You may as well get a new Parallel flow condenser as well, a generic that you can it the space of the old one. The condenser takes a lot of abuse and is a likely source for leaks.

for a shop to do this I would think 1-1.5k easy. if you do the legal parts your self 150 for a cond, 150-200 for a compressor,75 for hoses, 30 for flush.

You may find a shop that still works on R-12, or do a simple R134a conversion (fittings, flush, drier, evac, fill) but realize you are dealing with old parts that likely will fail under pressure, so if it works it may be short lived.

Welcome to the fun world of AC.
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post #3 of 4 (permalink) Old 04-15-2019, 04:28 PM
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I have just started to research and learn about auto AC systems, as I currently have 2 vehicles that have dead AC; the z being on of them. From what I have been reading if you simply charge the R12 system with R134a it will work. The OP claimed he did nothing other than fill with R134a. Granted it is not ideal, but he did so and claims that his system work fine? I wonder how this was done as the R134 and R12 have different fill valves.

Next I was looking for R12 fill and found a R12 direct replacement. Again I do not have any first hand experience, but this product claims that you can simply fill your R12 system with this new approved R12 substitute and it will run fine. Worth looking into.
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post #4 of 4 (permalink) Old 04-17-2019, 07:55 PM
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I used R12a from Canada on my 1987 Buick Grand National and it worked fine. It is compatible with R12 and R134a
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