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I realize that I can't be 100% sure that the hoses are the problem, but the hoses are the only part of the system that wasn't replaced or refurbished 2 years ago when I had to overhaul the AC system, and the very slow leakage symptom seems to fit if I can't find a leak anywhere else. Some background - after the original compressor seized up 2 years ago, I took the entire system apart to do a total AC system restoration. Replaced the compressor (rebuilt part), put in a new receiver dryer, new expansion valve and all new HBNR (green) O-rings & seals at every connection point. All the reused parts (condenser, evap core, hard lines & hoses) were removed from the car and thoroughly flushed internally and cleaned externally and inspected. The evaporator core looked brand new, other than a few dead spider carcasses in the plastic evap. case. Condenser looked decent for its age, and free of corrosion, but that was 2 years ago too - so I'm going to try to get a UV flashlight & the glasses to see if I can give the condenser a 2nd closer look.
Given that the old R12 hoses were never designed to handle the smaller molecules inherent to R134A or R152A refrigerants, and are over 30 years old, replacement wouldn't be a bad investment.
Pete - I agree the hoses are a likely culprit due to age etc. Just like pinhole leaks in the coils. Age isn't kind to equipment. I know systems that got switched from R22 to 410A usually didn't last long. They tended to pinhole quickly. Figure it has to to be similar to what the R134A/R152A stuff.
So sorry if these questions are redundant. This thread has been around for quite some time.
Reading through the thread I've gathered that R12 is hard to come by, bad for the ozone, and expensive. Currently my system is empty and I don't know the last time it worked. I opened the lines and nothing came out. So from what I picked up I have the options to charge my system with R134a/R152a or charge it using duster cans. The duster can method appears to be cheaper and works similar to the the R12 that was used in the FC. R134A/R152a can be used as well but the stock FC A/C lines were never designed to circulate those refrigerants.
For the duster can I do have a few questions:
If it safe to be inhaling the chemicals from a duster can? I only ask because it will be circulating through the system and going into the cabin and into my lungs.
Would I have to get R134a adapters to charge the system with duster cans? Is there an adapter to put onto duster cans so the A/C mechanic can transfer it into my A/C system?
Should I change the drier prior to charging with a duster can?
Do I need to introduce new refrigerant oil to the system after the mechanic vacuums out the system? If so what (ether or mineral oil) and how much if I'm using the duster can method?
Last edited by Gabriel82; Aug 6, 2019 at 01:47 PM.
So sorry if these questions are redundant. This thread has been around for quite some time.
Reading through the thread I've gathered that R12 is hard to come by, bad for the ozone, and expensive. Currently my system is empty and I don't know the last time it worked. I opened the lines and nothing came out. So from what I picked up I have the options to charge my system with R134a/R152a or charge it using duster cans. The duster can method appears to be cheaper and works similar to the the R12 that was used in the FC. R134A/R152a can be used as well but the stock FC A/C lines were never designed to circulate those refrigerants.
For the duster can I do have a few questions:
If it safe to be inhaling the chemicals from a duster can? I only ask because it will be circulating through the system and going into the cabin and into my lungs.
AC doesn't work that way. There is no contact between the refrigerant and the air. It's a closed system. Otherwise, how do you think the AC would continue to operate? Why would the refrigerant stay in the car? There are refrigeration systems that use propane, and ammonia, among other things.
Would I have to get R134a adapters to charge the system with duster cans? Is there an adapter to put onto duster cans so the A/C mechanic can transfer it into my A/C system?
No, you use whatever connections your AC has. Air dusters have no connectors, you use a piecing adapter to use them.
No AC shop is going to touch air dusters or a car with them.
Should I change the drier prior to charging with a duster can?
If the system has been exposed to air for more than a few minutes, yes.
Do I need to introduce new refrigerant oil to the system after the mechanic vacuums out the system? If so what (ether or mineral oil) and how much if I'm using the duster can method?
Probably. As I recall, R152 prefers Ester oil. Should be covered in the first few posts by Jack.
I've been very happy with it so far. Considering I'm in Colorado and the hottest we've seen this summer is about the high 90s, this obviously works better for me than others. While sitting still, and with the fan speed on the highest setting and temp all the way down and recirculate on, I get about 40-42F out of the vents. But with the car moving and all those settings the same, I've seen my breath lol; I've seen around 25F from the vents, although that was on a cooler day. On a hot day I saw about 35F while I was moving. However, I've been keeping the temp setting between the white and blue and fan speed around the middle because I've been having issues with the system freezing up (I'm guessing the evaporator). With those settings it's usually around 40F while I'm moving. If it does freeze up, I wait about 15-30 minutes to let it thaw, then I can use the AC again.
I've been very happy with it so far. Considering I'm in Colorado and the hottest we've seen this summer is about the high 90s, this obviously works better for me than others. While sitting still, and with the fan speed on the highest setting and temp all the way down and recirculate on, I get about 40-42F out of the vents. But with the car moving and all those settings the same, I've seen my breath lol; I've seen around 25F from the vents, although that was on a cooler day. On a hot day I saw about 35F while I was moving. However, I've been keeping the temp setting between the white and blue and fan speed around the middle because I've been having issues with the system freezing up (I'm guessing the evaporator). With those settings it's usually around 40F while I'm moving. If it does freeze up, I wait about 15-30 minutes to let it thaw, then I can use the AC again.
Has anyone else had this problem?
So you're saying that condensation on the evaporator is freezing up, but the compressor still continues to run? If so, you've got a bad thermal switch or faulty wiring. I'm not familiar with the FD's AC system, but suspect the basics are the same as an FC. On the FC, there is a normally closed thermal switch mounted on the evaporator, that is set to open when the temp gets below 33*F or so. This is wired in series with the refrigerant pressure switch (another NC switch, that opens when pressure goes below ~15psi, protecting the compressor if the system loses refrigerant) that supplies power to the coil of the AC compressor relay.
When the thermal switch is working properly, it will cut off the compressor before the evaporator starts to ice up, and cycle it back on when the evaporator temp rises back up above freezing.
So you're saying that condensation on the evaporator is freezing up, but the compressor still continues to run? If so, you've got a bad thermal switch or faulty wiring. I'm not familiar with the FD's AC system, but suspect the basics are the same as an FC. On the FC, there is a normally closed thermal switch mounted on the evaporator, that is set to open when the temp gets below 33*F or so. This is wired in series with the refrigerant pressure switch (another NC switch, that opens when pressure goes below ~15psi, protecting the compressor if the system loses refrigerant) that supplies power to the coil of the AC compressor relay.
When the thermal switch is working properly, it will cut off the compressor before the evaporator starts to ice up, and cycle it back on when the evaporator temp rises back up above freezing.
Actually, that's very likely what's happening lol. I completely forgot about the thermal switch and hadn't thought to check to see if the compressor was still running. I'll have to do that. Thanks!
Well I've tried a couple times now to get the AC to "freeze up" again and it won't do it. So, I guess that's...good? lol I'm happy it's working great, but it's a little frustrating because I wanted to see exactly what it was doing, to verify the thermal switch was shutting off the compressor and that there weren't other issues.
This thread will never die, and I'm going to be the one to revive it this time.
It's time to see if I can get the TII some working A/C. It worked ages ago and then stopped. I never bothered figuring out why. So today, I have replaced the receiver/drier, removed the compressor and filled with a couple ounces of ester oil, replaced the schrader valves, and replaced any O-ring on a fitting that was apart (two at compressor, two at redceiver/drier, and two going into the evaporator core at the firewall - evaporator was removed during my restoration). Everything is back together and I'm ready to pull a vacuum to see if I have leaks. My plan is to fill with R152a, thus reviving this thread. I was about to attach my manifold gauge set, but realized the directions seem to be at odds with the FSM.
I have a TII, and a Nippon Denso compressor. FSM (page U-40, 1991 FSM) shows low side at the firewall near the evaporator and high side at the drier. However, in this post, Jack says blue hose (low side) at the drier and high side above the exhaust manifold. Am I missing something or are we doing this backwards from what the FSM says? Am I in a social distancing fog and nothing makes sense anymore?
This is how I have things setup according to the FSM:
This seems correct to me, I just find it odd we've gone all these years and nobody else has asked this.
You have it connected correctly in your pictures, just like the FSM. BTW, the R152A works great - I'm going on 3 AC seasons with that stuff now since I restored my AC system. My original plan was to use the R152A just for testing, and then evacuate and charge with R12, but since it works just as good I didn't see the point in the expense of going back to R12.
When I did mine, I had a hard time fully charging it with R152A - it takes a lot of persuading to get it to ingest that 2nd can. Things to do to persuade a full charge are misting the condenser with a hose, and keeping the R152A can partially immersed in a bucket of warm water. Use a thermometer in the center vent, AC on max fan/recirculate, and when the temps bottom out, you're done charging. For reference, mine bottomed out at about 5~6*C.
You have it connected correctly in your pictures, just like the FSM. BTW, the R152A works great - I'm going on 3 AC seasons with that stuff now since I restored my AC system. My original plan was to use the R152A just for testing, and then evacuate and charge with R12, but since it works just as good I didn't see the point in the expense of going back to R12.
When I did mine, I had a hard time fully charging it with R152A - it takes a lot of persuading to get it to ingest that 2nd can. Things to do to persuade a full charge are misting the condenser with a hose, and keeping the R152A can partially immersed in a bucket of warm water. Use a thermometer in the center vent, AC on max fan/recirculate, and when the temps bottom out, you're done charging. For reference, mine bottomed out at about 5~6*C.
Excellent. I turned on the pump last night and got it to the proper amount of vacuum. Let it run for about ten minutes longer, closed the valves and shut it off. Came out this morning and the gauge hadn't moved at all. Beautiful! Working from home right now and have two kids attempting to do school work, but maybe after dinner the car will have A/C. Time will tell.
Hey Jerry- You have it hooked up correctly. Blue hose does not hook to the dryer. That post from years ago was a fat-finger. The dryer is on the high side, so of course you don't hook the low side hose to it...
It is possible. My '89T2 was blowing cold from its build date till summer 2011, when one of the O rings at the receiver/dryer gave out. At that time, I replaced the dryer & those O rings, had a shop evacuate & charge it with R12. It worked that way till summer 2017, when the compressor seized up. I would add that that compressor failure was a self-inflicted F-up. Prior to that summer, I built a new 13BT for the car, upgraded turbo, fuel system, aftermarket ECU, etc, etc... In the process, I managed to bugger up the A/C wiring, where the A/C refrigerant pressure switch was no longer protecting the compressor - it should have disengaged the compressor clutch when there was a loss of refrigerant. It didn't, so the compressor failed as a result. At that point I picked up a reman compressor, new receiver/dryer, all new AC system O rings & seals and I totally restored the A/C system and charged it with R152A. It's been working fine since.
You mean it never discharged in 30 years????
Is it still with R12 inside????
Yup, never discharged nor added any refrigerant, and the caps have never been removed.
In anticipation of problems, do have 2-30 lb containers of R-12 in the garage along with 24 cans of
Freeze 12 (not everyone's choice) that came with the SnapOn A/C Recovery machine I purchased many years ago.
Did give a couple cans of the Freeze 12 away to a fellow that was in need.
Originally Posted by jackhild59
I just might for a little while. I'm about to get my 10th Anniversary back on the road. With A/C of course!
Did have my eyes on your convert, but just too far away to take the plunge.
Yup, never discharged nor added any refrigerant, and the caps have never been removed.
In anticipation of problems, do have 2-30 lb containers of R-12 in the garage along with 24 cans of
Freeze 12 (not everyone's choice) that came with the SnapOn A/C Recovery machine I purchased many years ago.
Did give a couple cans of the Freeze 12 away to a fellow that was in need.
Did have my eyes on your convert, but just too far away to take the plunge.
I still have some cans of R12, but haven't seen the need to use them.
That vert would have driven from Dallas to NJ, no problem! Road trip to pick up cars is my favorite trip. I picked up an 04 SL600 near Philly last October and road tripped it home. We had a blast.
The worst thing you can do to an automotive A/C system is to *not* use it. The seals in the compressor shaft need to stay lubed to maintain the seal. Let them go dry, the refrigerant leaks out. Keep em lubed by running the A/C and the otherwise intact system will stay charged for many years of use.
And if you are interested also this is my self made Denso 10P15C compressor rebuild!
A perfect rebuild: i changed all gaskets, the carbon seal and the schrader valve!
Where did you get the parts to rebuild your compressor? I had a couple fail when I first started reinstalling my AC and I didn't know what I was doing, and I'm on my last compressor and I don't feel like paying $400 for one if this one fails someday haha.
Where did you get the parts to rebuild your compressor? I had a couple fail when I first started reinstalling my AC and I didn't know what I was doing, and I'm on my last compressor and I don't feel like paying $400 for one if this one fails someday haha.
Pay attention to order the right seal: there are 2 type of seals for our 10P15C compressor. The new seal type compressor started to appear on the RX7s on 89~90. The only way to know what type of seal is inside into our Denso 10P15C is to disassemble the compressor first! There is no way to find it with the serial number!
Seals are not interchangeable. There are 2 different housings, each one for one type of seal!
Also with the "one piece seal type" (the one in my compressor) you need also to buy the "seal lip tool". If you install the seal without this tool (the one you can see into one of my photos above) you will destroy the seal gasket and the system will leak!
My system discharged 50% after 8 months. I checked everything, everything was perfect even the vaacum test!
With the leak detector i found a micro micro micro leak on the schraders valves (both of them). I replaced all the schraders valves even the one into the compressor low side pipe (the 3rth vale)!
Without the electronic leak detector i would never have found the leak! You simply can't find these micro micro leaks without the leak detector or with the "UV" test!
Last edited by Venturer; Mar 31, 2020 at 06:54 AM.
