Need to get some gauges on it.

 

It’s full of R12, or rather with in proper range when working. I took it to a shop. They said it was little bit low but not enough to stop it from working. For the age of the car I think that’s good. They topped it off just to be sure. But gauges show levels are good.

 

Does it run long enough to freeze up the expansion valve?
The drier eyeglass is suppose to be clear when it's on, I was hoping you knew actual pressure readings .
What conclusion did the shop have?

 

When it works it works till I park the car for the night. 1 hour or 5 hours, or if I am running around all day, it stays working. The next day it could be 50/50 if when I crank it up if it will work. I haven’t opened up to the expansion valve yet. Hoping to avoid that or draining the system. R12 not easy to get in my area.

Shop could not determine the problem. Kept it for a few hours, gauges always looked good. But it was working that day. Let it run for a good while, ice cold air & normal readings. Sorry I don’t remember the readings.

The dryer eyeglass is supposed to be clear? That’s odd. It’s “clear” I guess you could say when it’s not working. Looks like a clear liquid in it you can barely see that don’t appear to be moving. When it’s working it’s a whiteish color, like liquid frost I guess, & very visual different that you can clearly see is “flowing” by how turbulent it is. So why is mine backwards?

 

Only thing that don’t appear to working properly is the fans. Last summer the condenser fan was working, it’s now gone bad. Going to order a dorman replacement.

But when the AC is on the radiator fan is also supposed to cut on & stay on. It don’t. It still cuts on & off like it’s cooling the engine. But it doesn’t come on & stay on unless the AC decides to blow cold air. Compressor clutch always engages like normal.

 

If the other fan still cuts on and off as if the AC is off then the problem isn’t the fan. Is the light on the AC button on?

Does the compressor cycle?

I’ve never seen a fan on these cars fully go bad.

 

Yes the light on the AC button is on. Stays on & does not flash like other posts on here have described.

If by cycle you mean clutch disengages & engages on & off. No not that that I’ve seen, but i also don’t know if I watched it long enough when it was working. I’ll watch it tomorrow, if it decides to work. But I’ve always had it wide open & max cold. I didn’t think it would ever get cold enough in the car to cycle on & off.

Well radiator fan will cut on & off like normal to keep car from over heating. Will continue to operate like that if AC is not blowing cold air. Will turn on constantly if AC is blowing cold air. The condenser fan is not moving at all. It might move a hair, like you bumped it, every now & then. Like it’s trying to run but motor can’t “start up”.

 

Is your evaporator drain pipe clear and letting water out when cooling? If water stays around the evaporator it will freeze and the evaporator won't be able to exchange air until it melts, resulting in intermittent warm/cold air.

That might also trip the thermistor on the evaporator too, which would put the system in AC-off mode and the fans would go back to normal operation.

 

Maybe if the condensor fan isn't working, the pressure is getting too high and shutting off via the pressure switch?

 

how about an excessive build-up of dirt blockage from the fresh air intake vents buried down behind the lower under dash area?

 

Yes water line is clear. When working, water comes out from under the car at the drain line.

Condenser fan was not running yesterday, but AC was blowing cold air (radiator fan did cut on & stayed on). Besides if one of the pressures switches tripped the AC clutch would disengage. It don’t, it stays engaged. But it’s like the R12 is not moving.

As far as I can tell vents look clean & I have a good deal of air flow when the system is on high.

I’m just at a loss on why it’s acting like it is. Why is AC clutch engaged, but fans not acting like the AC is on, & with the compressor running why does it look like no R12 is moving in the viewport.

 

If the clutch is engaged, the compressor should be mechanically pushing refrigerant through, fan or no fan. If it isn’t, the compressor is intermittently not building pressure due to a blockage or wear.

So when it does cool, it never cycles? That’s also not right.

 

So my compressor is going bad & not building up pressure, or a blockage. Either way requires draining of the system. That stinks. No one around me is capable of capturing the R12 & it’s hard to come by.

as far as cycling, how long is it supposed to run between cycling? Would it cycle at max cool, even on a hot day. Should I set the temp higher & see if it cycles then while watching outside the car?

I was always told while troubleshooting to turn it all the way down to prevent it from cycling. While driving the car runs so quite & smooth I can’t tell when the compressor is running & when it’s not.

 

The intermittent nature of the problem is unusual. The compressor is capable of building pressure according to the shop you brought it to, and it's even within range according to them. Here's a video on checking for blockages by measuring the temperature.

I would suggest to look into the fan first. I used the original Denso fan from 1995-2020 until the bearing started to get a little loose, at which point I changed to an aftermarket (TYC 610150) fan. Make sure both fans are running when the AC is supposed to be cooling.

 

I’ll get a temp gun & look if there might be a blockage. But what he is describing is not what mine is doing. It’s not cooling, then not cooling. When I start the car it’s 50/50 it will work. If it don’t, it don’t start working as I drive along. But if I crank it & it works, it stays working all day. Till I go to bed for the night & the next day it’s another 50/50 chance.

I’m going to try to put power directly to the fan to make sure it’s bad. If it is I can order A denso one for $72 to replace it. Also both fans don’t come on, or at least the radiator fan, don’t come on unless the AC decides it’s wants to blow cold air that day. But everything else functions & acts as if the AC is working. AC clutch, ECU telling engine to idle up, AC button, relays click over. It’s just odd.

 

Is there a relay for the AC fan? Check that first, before buying a new fan.

 

The Factory Service Manual troubleshooting section for AC states to check the following in order of priority in the category of "compressor operates intermittently""

1. Inspect volume of refrigerant
2. Inspect cooling system for refrigerant (not sure how that's different than 1, but whatever)
3. Pressure switch
4. AC amplifier
5. Thermistor
6. Wiring and wiring connections

 

The only relays I know of are the 3 under the hood & the 1 behind the right kick panel. They are good. Or test good & if unplugged stuff stops working.

Well I did 1. 2 likely mean checking the view port on the dryer, I can see R12 in it. 3 pressure switches appear ok. Test ok & if disconnected nothing works. 4. I’m guessing AC amp is ok. All I can find is to check is signal is going out & it appears to be sending signal to turn stuff on. 5 thermistor maybe, but you would think if it was bad it would tell the compressor to turn off. 6 wiring is where I’m left.

If there is no valve in the compressor that needs to be opened, & it’s not getting a signal to open. Then the clutch might be slipping or something is stopping the R12 from moving. But that don’t explain why the fans don’t come on, unless it decides to let the R12 move.

that’s why I posted on here to ask. It’s like I’m missing something, but I don’t know what else there could be.

 

You should test/replace the fan first and go from there, in my opinion.

 

Ok. I’m guessing condenser fan is bad. With AC on I get 14 volts at the plug, but fan don’t run. Fan also has a reading of 0.51 ohms. I’m almost sure that should be lower. I’ll order the Dorman brand one tomorrow. Anyone know if it’s a good brand?

While looking I noticed 1 of the wires for the magnetic clutch on the compressor looked a little pinched on the compressor frame. It hit me this problem came after having the harmonic balancer replaced last year. So I move the wire where it was sitting up & not laying on the metal casing of the compressor. Cranked the car & instant cold air. Could be coincidence, I’ll see over next few days I guess.

is it possible that sometimes power was being leached away from the clutch keeping it from fully engaging. It was spinning but maybe without full power it was slipping on the compressor?

Oh while it was working I turned it to 1/2 cool & 1/2 fan speed & watched the compressor. It started cycling after a minute or so.

 

If the compressor is kicking on then it should be cooling. When the engine is cold and radiator/condenser are cold then it should at least cool for a minute even if the fan(s) are not working.

The sight glass should look clear when the compressor is on. When you shut the AC/compressor off you should see bubbles in the sight glass. When the compressor kicks back on it should clear up again.

Is the high pressure tubes getting hot and the low pressure tubes getting cold when the compressor is on (like near the firewall)?

I was going to say that there is a flap in the vents that directs the air into or not into the heater core, and if that were not working you would be blowing to cold air through the heater core and heating it possibly if the cables weren't working properly. Moving the lever to cool should close the coolant valve on the firewall to prevent hot coolant from flowing into the heater core and another cable should move the flap to direct air around the heater core. None of this matters if you say you have kept the lever at cool for all this time when it has worked or not worked.

I didn't think Denso had the condenser fan. I had to buy one from Toyota a few years back because mine started rattling from a bad bearing/bushing.

 

+1 You can't tell all liquid (without bubbles) or all gas moving in there. You can notice a difference in light diffraction if you've seen when the compressor turns on or off. That's when you'll see the receiver fill up with liquid or flash off to gas.

When it wasn't cooling, as the magnetic clutch still engaged? Or did it come unengaged? One problem with old clutches is the "gap" opened up, and you won't get the needed clamping force. That extra gap can be reduced by adjusting the shim washer thickness.

Here's a video on shims:

 

+1 You can't tell all liquid (without bubbles) or all gas moving in there. You can notice a difference in light diffraction if you've seen when the compressor turns on or off. That's when you'll see the receiver fill up with liquid or flash off to gas.

When it wasn't cooling, as the magnetic clutch still engaged? Or did it come unengaged? One problem with old clutches is the "gap" opened up, and you won't get the needed clamping force. That extra gap can be reduced by adjusting the shim washer thickness.

Here's a video on shims:

That must be what I’m seeing. It looks like a liquid in it at start of the day or if it’s not working. But if it’s putting out cold air, it turn white looking. Guess that’s it flashing to gas it light refraction.

the clutch was always was spinning with the pulley when AC was turned on. Cold air or not. But in my previous post I noticed tonight one of the clutch wires looked pinched. I’m wondering if it might have been losing power & not engaging with enough force. I guess I will know if it stays working over the next few days. I’ll check the gap also.

thanks for the info everyone.

 

Sorry drZ I missed your post.

mine car is a Japan import version. It has a fan in front of the condenser. I’m going on 300k miles. Guess it was just its time to die. It’s still a original part.

my eye is not clear when AC is running. It has more of a whiteish look. Like moving frost I guess you could say. When it cuts off it clears up some. If I look at it 1st thing after its sits overnight it’s clear, well clear liquid.

yes AC lines get hot/cold when it’s “working”.
No they don’t when it’s not working, even with compressor clutch engaged.

Vet flaps work. I can hear them moving & when AC works it’s cold, I mean COLD.

 

mine car is a Japan import version. It has a fan in front of the condenser. I’m going on 300k miles. Guess it was just its time to die. It’s still a original part.

my eye is not clear when AC is running. It has more of a whiteish look. Like moving frost I guess you could say. When it cuts off it clears up some. If I look at it 1st thing after its sits overnight it’s clear, well clear liquid.

Japan built or not, they all have the condenser fan in the front. A bit of a bear getting to the condenser fan. You need to take off some of the front grill and maybe the plastic part of the bumper, I can't remember precisely. I went with a new Toyota motor after my bad experience with the radiator fan motor from Duralast.

Ideally, the sight glass would be clear when the compressor is running, but I know what you mean. You will still see some small bubbles go sailing by.

I would think if the magnet clutch was only half engaging that you would here screeching and/or you would have worn out the clutch in short order. Is it possible you thought the magnet clutch was engaging because the engine would idle-up a little but the clutch was actually not engaging, or were you actually observing the compressor pulley?

 

If going aftermarket, I would recommend TYC.

 

Maybe that bad wire was causing the clutch to disengage.

 

Clutch never stopped spinning with the pulley. So it had to be causing some other issue, or preventing the electromagnet from getting enough power to fully engage. Or had nothing to do with anything LOL.

AC working again today. But my local dealership can’t get me a replacement fan, can only find sight that is sketchy claiming to have a genuine part. Guess I’ll have to settle for a aftermarket.

 

Does AC always work when you're fast on the highways?

You can get a TYC fan from rockauto. A few days of shipping time shouldn't matter at this point. $49.79 with lifetime warranty. You pay return shipping when the warranty time comes using rockauto's discount rate in the online claims process. I don't remember but I think for warranty claims they ship it out to you free?

For 93 1.8L: 1993 TOYOTA COROLLA 1.8L L4 A/C Condenser Fan Assembly | RockAuto

And use the 5% off discount code if you buy from rockauto, scroll to the newest post:
RockAuto Discount Code

If the sightglass looks foamy, then you're slightly low on refrigerant. When you look at the sightglass first thing in the morning, it's clear because it's full of gas. That what all gas looks like.

This is what bubbles, or foams, in the sightglass looks like:

 

For what it's worth, my AC system with all 2020 Denso components never had the bubble show exactly like how it says in the manual. It's more of a guide than the rule. I wouldn't put too much stock in the bubble.

 

Would that be R134a then? R134a sightglass is said to be less reliable as some PAG oils can foam even under full condition.

In OP's case the "traditional" R12 readings should still hold I think.

 

Good point. That's right, R134a. No experience with R12.

 

And if you do have to open the system, you can vacuum/recover the R12 and reuse it after the repair. Otherwise, you can convert it to R134A and it will work just as well.
I converted my old '93 Corolla to R134A with a retrofit kit, and without changing the oil, and that AC worked great for the four more years I had that car.

 

JohnGD

AC worked Or didn’t work. Speed did not matter. Everything would appear to be working, no cold air & no “white look” in my view port. Like R12 was not moving it it was just a liquid sitting there.

yea I’ll likely order that from rock auto. Little choice.

It’s not foamy per say. Just looks white. I guess the bubbles could be so small I can’t see them like in that video. I have a photo (don’t know how to post a video). But mine is clearer when not running, whiteish when running. Had a shop that had some R12, they said they topped it off. Guess they could have lied.

Peat.

no one remotely near me able to capture the R12 sadly.

but it has worked fine today after moving that wire.