Quote:
Originally Posted by jackhild59
If that temp switch is gimp, you could have attained vacuum on the low side, but not that likely.
I would advise to charge a couple of oz of liquid refrigerant into the system then run the car until everything gets good and hot. Go back to the spray bottle and look for your leak.
Pro's use nitrogen and pressure the system up to 200psi to look for leaks.
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Looks like pulling the temp switch out for testing will be a major PITA, since it's attached to the evap core. I suspect it's fine, given how it's wired in the electrical circuit and the symptoms - I have minimal cooling which means the core is well above the freezing point; compressor runs so I know the switch is normally closed as it should be. What I won't know w/o testing is if the switch will open when temps drop below freezing. For now I guess I'll take that risk, evacuate the system and see if it holds a deep vacuum. If the vacuum holds, any leak that exists is of the slow/dynamic variety (i.e., happens only when system is running, normal operating shock/vibe/temp environments). If the vacuum doesn't hold, then I'll need to find & fix the leak before doing anything else.
Quote:
Originally Posted by jackhild59
I recommend you replace the receiver/drier. The descant-bead retaining bag is soluble in synthetic oils. You do not want those bead spread throughout your system. Any modern (post 1996) manufactured desiccant is designed for R134a and synthetic oils.
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Agreed, this is inexpensive insurance. I guess the only question is are these post-'96 receiver/dryers compatible with R12 and will any residual trace amounts of mineral oil that may be left behind in the system after evacuating cause problems assuming I switch to an Ester oil lube on recharge? Unless I crack open lines & remove the compressor to physically drain it, there will be
some mineral oil left behind. I was hoping that replacing the receiver/dryer with a new one and the evacuation procedure would suck out enough of the old mineral oil so that a physical tear down & chemical flush of the rest of the system's components would not be necessary.
Quote:
Originally Posted by jackhild59
Also,be aware that there are two different systems on the FC. One is installed in Japan and the other was installed at the port of entry. Type is not related to Sanden/Nippondenso system. If you lookup the part number at nearly ANY parts store, they always get the wrong one. Take your old part in with you to save the trip. An easy way to distinguish is the hold down bracket for the drier. If your bracket is welded on, get a replacement that is welded on. If it is clamp on, get the drier that is clamp on.
Whether you recharge w/R12 or Freeze12, use Ester oil for lube. Add a couple of oz of oil to make up for losses around the compressor seal. DO NOT use PAG in any system that has pretty much ever had mineral oil or R12 in it. Bad reaction. I don't know if you can easily even find mineral oil any more.
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Interesting - I was aware that some FC A/C systems were port installed (US) and some were factory (Japan), but I thought all the ND systems were factory installed, and all the Sanden systems were of the port/dealer installed variety. Reason being is I believe all the USDM turbo models shipped with factory A/C, and I've never seen a Sanden system installed in a turbo. I have seen Sanden systems in the base model RX-7's, which were likely port/dealer installed options. I didn't know Mazda mixed & matched those pedigree variations. Good tip on the bracket - no doubt will save me some grief when ordering parts!
Since I don't have a vacuum pump to evacuate the system, I'll have to farm part of this job out. Fortunately I found a local shop who will work with R12 and seems competent and charges pretty reasonable rates. Game plan is to bring it to him to evacuate the system & recycle whatever R12 I have left. If the evacuation shows I have no leaks (holds deep vacuum for a long time), I will take the car home & install a new receiver/dryer. Then bring it back, have the system evacuated again and charged to spec with R12, Ester oil lube and some leak detect dye. If it doesn't hold vacuum on the first evacuation, I'll have him test for leaks with the pressurized nitrogen, and depending on what he finds, I'll either have him fix it there or fix it myself and bring it back for evac/charging as previously described.
Thanks for the help!