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what to do about A/C not working?

Old 05-16-2019, 08:42 AM
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what to do about A/C not working?

1986 4Runner 22re 5spd.

The A/C was not working when I got the truck and since I had so many things to fix, I concentrated on necessities first. But I really would like to have it working as we get some very uncomfortable humidity in the summer.

Here's the status:
+ All the parts are in place and accounted for.
+ The A/C would do nothing when I attempted to turn it on. The "A/C" switch lights up.
+ When I put 12V directly to the compressor last night, I get a strong click. I think the solenoid works.
+ Grabbing the hub of the compressor and turning it moves well and feels OK. Not seized.
+ When I pushed in on the schrader valve with my fingernail, I can see there is some pressure present in the system
+ Some previous owner was doing research on the A/C system as is evidenced by a Haynes service manual I received with the truck and some notes.
+ I found some what appears to be O-ring kit for the A/C in the box of spare parts I got with the truck. Looks unused.

- the idle up vacuum switch had a broken nipple and I fixed that, but testing it with 12V I get no action so I think it's bad.
- I don't know for sure if the system still has R12 in it or R134(doubt it though) Any way to test?
- previous owner did no work on the truck himself as far as I can tell and I don't recall discussing A/C with him other than maybe it wasn't working at the time of purchase.

I could buy a can of R12 off ebay and see what happens, or do the whole conversion to R134 but I haven't been deep into an A/C system before. Only done recharges on Daily Drivers.
I know you are not supposed to mix the refrigerants and oils.

What would you guys do ?
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Old 05-16-2019, 09:01 AM
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If a R134 conversion has been done by a professional shop, adaptor fittings standard for the newer refrigerant should have been left installed on both the high pressure and low pressure service ports.

If it was mine and still original, I'd keep it R12, but then, I still have a substantial stash
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Old 05-16-2019, 09:03 AM
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my A/C system seems to be very different from yours. I do not have any of the mentioned parts, and it is turned on by opening the small triangular windows in in the forward area of the doors
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Old 05-16-2019, 11:07 AM
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Originally Posted by keycw View Post
my A/C system seems to be very different from yours. I do not have any of the mentioned parts, and it is turned on by opening the small triangular windows in in the forward area of the doors
Ha! I have that system also for redundancy. That one is still working fine and will be even better when I take the top of this month.
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Old 05-16-2019, 11:09 AM
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Originally Posted by millball View Post
If a R134 conversion has been done by a professional shop, adaptor fittings standard for the newer refrigerant should have been left installed on both the high pressure and low pressure service ports.

If it was mine and still original, I'd keep it R12, but then, I still have a substantial stash
Ah! good point. No "different-than-original" fittings are present.

Can you think of anything else I can do by way of observation or test to determine if the system is usable?
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Old 05-16-2019, 11:12 AM
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Originally Posted by Melrose 4r View Post
Ah! good point. No "different-than-original" fittings are present.

Can you think of anything else I can do by way of observation or test to determine if the system is usable?
First thing to is draw a good vacuum on it and see if it holds.
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Old 05-16-2019, 12:18 PM
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OK, just found out the oem A/C vac switching valves are still available from 22re performance so I just ordered one.
Recently acquired a vac pump so I'll have to figure out how to apply it to this.
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Old 05-16-2019, 12:44 PM
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Aren't vacuum and pressure interchangeable in this case?

I'd probably tackle the electrical first and see if I could get the AC amplifier (AC brain) to activate the clutch wire. It needs an RPM signal, a pressure switch signal and I think one other signal I am forgetting. These are all listed in the AC diagnostics with thier inputs. It could be as simple as someone twisted the AC rpm cut off knob.
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Old 05-16-2019, 02:33 PM
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Originally Posted by keycw View Post
my A/C system seems to be very different from yours. I do not have any of the mentioned parts, and it is turned on by opening the small triangular windows in in the forward area of the doors
You have a 260 A/C, (two windows, 60 mph)

Originally Posted by millball View Post
First thing to is draw a good vacuum on it and see if it holds.
Originally Posted by Co_94_PU View Post
Aren't vacuum and pressure interchangeable in this case?
.
Originally Posted by Melrose 4r View Post
OK, just found out the oem A/C vac switching valves are still available from 22re performance so I just ordered one.
Recently acquired a vac pump so I'll have to figure out how to apply it to this.
The proper leak check for an A/C system is to evacuate the refrigerant using the proper A/C charge/discharge equipment and then pull a vacuum on the system. You then monitor it for loss of vacuum (pressure increase if you like) This is also a required step before recharging a system that has been opened up for repair in order to remove moisture form the system. I have only done this a few times, (this is Alaska and 260 or 460 air con works fine most of the time). If a leak is detected a shop would generally pressure up the system with refrigerant and use a leak detector to locate it. I doubt you can find loaner/rental equipment for that.
The cheap and easy recharge method is to do like you mentioned earlier and just use one of the off the shelf recharge kits.
The best way for you to proceed would be to find the pressure switch (locks out the compressor operation if you have an inadequate refrigerant charge) and check the wiring schematics or troubleshooting guide to determine if the contacts are open or closed with a meter and see if they are supposed to be open or closed when the pressure is low.
If you determine that you have a low charge it is almost guaranteed that you have a leak, no telling how bad or where, but you can do the recharge and see if it works and for how long.
A good shop with an A/C charging station and leak detection can take a lot of mystery out of it and in my opinion is the right thing to do so you don't just waste refrigerant.
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Old 05-18-2019, 05:51 AM
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Originally Posted by Melrose 4r View Post
...
+ When I pushed in on the schrader valve with my fingernail, I can see there is some pressure present in the system
...
That's a good way to get blinded. Also, you're wrecking the ozone layer and giving all of us skin cancer. Please don't do it again.

The A/C idle-up has nothing to do with whether A/C gets cold (it just inches up the idle when the ECM commands the compressor to start). Worry about that later.

While it seems unlikely given the history, you might have sufficient refrigerant charge. You could try putting 12v to the compressor clutch with the engine running (without idle-up, you might have to open the throttle slightly to keep it from stalling). If you can get cold air within 30 seconds, the charge is okay and your problem lies with the electronics. Don't waste too much time on this; if the refrigerant charge is low that, by itself, will keep the ECM from commanding the compressor to start.

IF you have any charge at all (it sounds like you do), then you can't work on finding a leak until you get that evacuated. So I'm with akwheeler; you should just break down and take it to a shop to get it evacuated. They might be able to quickly tell you what's wrong.

If, after you learn what's wrong, you end up doing your own repairs, here's all I know about A/C: https://www.yotatech.com/forums/f116...-r134a-284801/
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Old 05-18-2019, 07:39 AM
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I have the same A/C system that was developed for the 1924 Hupmobile. The 260. I have A/C parts from a junker in a Rubbermaid tote with the intention of installing them someday. Subscribed to see how this plays out. IIRC if you convert to the new coolant you're supposed to change all the O rings to the green ones and replace the drier.
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Old 05-18-2019, 08:16 AM
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I converted the AC compressor in my '87 to onboard air.

Puts out as much, or more air, than my 5 horse Speedaire at less than 2000 revs.

A few pics in a couple posts page 277 of the ' What did you do to your rig today' thread.

Last edited by millball; 05-18-2019 at 08:21 AM.
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Old 05-18-2019, 07:30 PM
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Originally Posted by scope103 View Post
That's a good way to get blinded. Also, you're wrecking the ozone layer and giving all of us skin cancer. Please don't do it again.

The A/C idle-up has nothing to do with whether A/C gets cold (it just inches up the idle when the ECM commands the compressor to start). Worry about that later.

While it seems unlikely given the history, you might have sufficient refrigerant charge. You could try putting 12v to the compressor clutch with the engine running (without idle-up, you might have to open the throttle slightly to keep it from stalling). If you can get cold air within 30 seconds, the charge is okay and your problem lies with the electronics. Don't waste too much time on this; if the refrigerant charge is low that, by itself, will keep the ECM from commanding the compressor to start.

IF you have any charge at all (it sounds like you do), then you can't work on finding a leak until you get that evacuated. So I'm with akwheeler; you should just break down and take it to a shop to get it evacuated. They might be able to quickly tell you what's wrong.

If, after you learn what's wrong, you end up doing your own repairs, here's all I know about A/C: https://www.yotatech.com/forums/f116...-r134a-284801/
Thanks for your thoughts and link to your excellent post which i had found in the past but am happy to find again. If we still had a “THANK” button...
Sorry to hear about your skin cancer.
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Old 05-18-2019, 07:33 PM
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Originally Posted by millball View Post
I converted the AC compressor in my '87 to onboard air.

Puts out as much, or more air, than my 5 horse Speedaire at less than 2000 revs.

A few pics in a couple posts page 277 of the ' What did you do to your rig today' thread.
That’s pretty cool. I always wondered how that would work with an A/C compressor. I used the the AIR injection pump on my Datsun 210 to blow up air matresses camping in 1989. Also tried to make a supercharger out of one once.
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Old 05-18-2019, 07:34 PM
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Originally Posted by nervo19 View Post
i have the same a/c system that was developed for the 1924 hupmobile. The 260. I have a/c parts from a junker in a rubbermaid tote with the intention of installing them someday. Subscribed to see how this plays out. Iirc if you convert to the new coolant you're supposed to change all the o rings to the green ones and replace the drier.
thank
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Old 05-18-2019, 07:45 PM
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Thanks everybody for the input. I will check around but i don’t think i will be able to find a shop who will be willing to work with the R12 system without converting it. My theory is the system is simply low on pressure and not coming on because of that. So i will borrow a gauge set from a buddy and confirm and if that’s it just get a can or two of R12 off ebay and recharge it. The factory service manual shows the steps.
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