Fixing A/C and finding suitable parts

[mdcc2010]

I've started restoring the A/C system on my RX, and it has not been an easy journey as far as parts go. Mostly this is because the system is Panasonic, which has a couple odd parts, namely the receiver drier: it has the pressure switch screwed into the drier body as opposed to most other cars (and the Hitachi system) where the pressure switch has a place on the refrigerant line between the condenser and the drier. I tried one (made by Metra or something like that) that looked correct and was specified for the '88 Panasonic system, but it is very wrong: the IN and OUT ports are reversed, its fittings are the wrong thread size, and it doesn't have a place for the pressure switch to be mounted, not to mention that it's taller and slimmer than the original so it wouldn't fit quite right regardless.

Now, I can use the interwebs to find about 10 different drier models that say they fit this system, and they may look compatible judging by the right-angle flanges, but none provide any real information (namely about the port size, flow direction, and the pressure switch fitting) and I'd rather not have to buy all 10 of them just to find one (or none) that work. Does anybody know of a tried-and-true replacement? I'll call the dealer to see if they offer one with the new R134a-type dessicant for a reasonable price.

 

The other part that can be problematic is the thermal expansion valve: the Hitachi system has a third, smaller refrigerant tube with a fitting in addition to the two main fittings and the thermal bulb whereas the Panasonic system lacks this third tube. Most places will say that the Hitachi valve fits the Panasonic system; it does not. I decided I didn't want to play with it, so I just replaced the o-rings and put the original valve back on since there were no overt signs of failure or contamination or anything. If I do end up replacing it, my '88 RX-7 uses the same style valve (I know because last year I restored my 7's A/C system), so I'll order one for that car instead.

 

Otherwise, a generic HBNR o-ring set and R134a adapter kit are all I needed. I decided to use POE oil instead of PAG because the original compressor is still good and PAG supposedly doesn't like residual mineral oil and any chlorine that may have been left behind by the old R12 charge. I've already drained the old oil from the compressor and reinstalled it, flushed the evaporator and condenser, and replaced all of the o-rings. Once I have the proper receiver drier, I can oil up the compressor, evac the system, and charge it. I also modified the HVAC control so that I can run the A/C system (or not run it) in any climate control position.

[mdcc2010]

So I called the dealer and a replacement receiver drier is about $55, so I just ordered one through them; it's cheaper and more gratifying than playing internet store roulette (and AutoZone et al don't offer any at all). The part number I was given is SOA 438A216.

[presslab]

I remember a few years ago having this problem in my '88 GL-10, and I found the 4-Seasons 33445, maybe it's similar to yours.  But that one isn't much cheaper than the SOA one, so I'd say you did just fine by going with the factory.

 

The TXV will have a different superheat setting for r134a, so if you're going to run that you might want to change it.  I didn't change mine as I use the hydrocarbon refrigerant.

 

POE doesn't lubricate as well as PAG but it's definitely better for compatibility.

 

How did you modify the HVAC controls?

[two85s]

Hi all, presslab said, "

The TXV will have a different superheat setting for r134a, so if
you're going to run that you might want to change it.

How did you modify the HVAC controls?  " 

I wanted to ask where could the right TXV valve be purchased?  I am doing this to my 85 GL wagon.  I was told to use "Ester" oil for the compressor. Also I would like to know about modifying the HVAC controls too.  Thanks very much, Aaron

[presslab]

I have not changed the TXV as I don't use R134a, I use ES-12a.  I imagine a TXV from a newer car would fit but I'm not sure.

 

POE aka Ester oil is okay, but it has downsides.  It doesn't lubricate as well as PAG or mineral oil.  The upside is that POE is compatible with any refrigerant.

[two85s]

Hey, thanks very much for your response and information.  Very much appreciated.  Aaron

[Zekeuyasha]

Anyone know of any bolt-on compatible condenser coils or where an oem coil can be found?

[two85s]

Hi all, anyone know where to find online or have a copy of the A/C section of the 1985 FSM.  I have a 1985 FSM 1800 Sedan and Wagon with sections 1-6, but no A/C section.  I am doing this swap and having questions that the AC section would help a lot.  Let me know... sure appreciate it. Aaron

[two85s]

Hey, thanks all. I found a source for the AC section.  Cheers, Aaron

[aba4430]

Hey, thanks all. I found a source for the AC section.  Cheers, Aaron

Hi,

Can you let me know where you found this section.  I have been looking for this information for a while as well.  The A/C in my 87 Brat works, but I would like to fix the vacuum A/C idle up feature on the Brat.  Thx.

[two85s]

Hey aba4430, yes I thought I had the definitive FSM chapters 1-6 set until I started this a/c r12 to r134a swap project.  I looked and asked and found out this supplement covers a/c and a bonus electrical section.  Also, there is a 'Book 7', which has other info, not sure what about.  I bought the second FSM book sec. 4-6, and both supplemental books from a seller on ebay and it should be here today.  I can direct you to another source I found where you could get a hard copy of the a/c supplement for yourself, but you should PM for that as I think the supply is very limited. THIS IS FOR A 1985, remember.  Others on USMB know much more than me and may help too.  Either way let me know if/ how I can help.  I would be glad to help, Aaron