A/C gurus help (1 Viewer)

[Vasiliy]

Hello everyone. The problem with my car is that hot air comes from all evaporators.

There is JDM LC80 with R12 gas, 3 evaporators(front, rear, fridge)
Outside temperature +27(80f) - +30(86f) humidity is not more than 30% (we have a dry climate) the condenser fan turns on with the compressor (mod) The coolant radiator is replaced by an analog one, pump, thermostat, radiator cap, coolant, are new original brand!
I was replacing condenser(thought it was leaking) so I added 30ml mineral oil(1Oz) I replaced TXV on fridge it was blocked, some dead orings. After this I don't have cold air anymore. The TXV on fridge is not original, is UAC brand but fits like original, so now my fridge always receives freon inside(rear AC or front AC or both AC is on)

Front TXV and dehumidifier are new (5 years) and then I washed the evaporator and set the cabin filter (mod) so it's still pretty clean. In the past on the hottest day under the sun on MAX blowing with recirculation, I could achieve +4 (+39.2f)from center vent, I think the problem is not in TXV because both evaporators blow at the same temperature (almost)( fridge is colder)

By the way, while fast driving, it seems like I get more cold from vent, but again not north pole ICE, the compressor constantly is working without cycling just like before, in rare cases while fast driving and at +10(+50f) on rainy day or night, it is cycling with vent temp +6 (42.8f)- +7 (44.6f)

The first photos in a calm state

 

[Vasiliy]

AC is on, at Idle

 

[Vasiliy]

Condenser fan is off manually, at idle

 

[Vasiliy]

The pressure drops if the fan is turned on + we water it, the temperature in the cabin drops slightly.

 

[Vasiliy]

Last photo 10 liters(2.64g) water I poured, then pressure and temperature begin to rise again. I forgot to mention, there is also a second fan that works normally by switch pressure, running for a while to drop pressure after turning off the AC or engine. Fan turns ON/OFF in the hot days or while car is too hot, so both fan will work.

 

[smritte]

Need pressure and center vent temp at 1300-1500 rpm both blowers on high. Run for 20 seconds and take reading. I want the lowest low gauge reading and highest high gauge.
1. Is compressor turning on and off when you do this?
2. Is the low gauge dropping under 20 psi?
3. Is the high gauge going over 450 psi?

This is basically stress testing the system. The TXV controls the low side and the condenser/eng fan control the high side. The blower on high is putting max heat into the evaporators, the condenser/engine fan is removing it.

@ 85f High gauge should run 200psi - 270psi. Low gauge 15psi - 25psi.
A/C is not exact. should be "close" to this

1. Low gauge dropping under 15 psi and compressor shutting off, high gauge low (150psi ish) Low on, refrigerant and or oil.
2 High gauge going over 350psi. Too much refrigerant and or oil and or condenser not removing heat and or clutch fan not engaging completely (air flow).

This should get you started.

 

[smritte]

I forgot to ask this. Does your vehicle actually have R-12 in it? I ask this because It's extremely rare in most countries. If you run an "R-12 Blend" refrigerant, that changes everything. If it has been converted to R-134 that changes things slightly.
I am also assuming when you replaced components that you put the vehicle into a solid vacuum for 20 mins with ambient temp over 75f.

 

[Vasiliy]

Thank for your good advice! I will try when the weather allows (tomorrow just +20c-68f cloudy)
I guess pressure measurement will be not accurate

I forgot to ask this. Does your vehicle actually have R-12 in it? I ask this because It's extremely rare in most countries. If you run an "R-12 Blend" refrigerant, that changes everything. If it has been converted to R-134 that changes things slightly.
I am also assuming when you replaced components that you put the vehicle into a solid vacuum for 20 mins with ambient temp over 75f.

Yes, it's pure R12 system, gas can with 13kg (28.6pound)
I have evacuated the system for at least 2 hours. I think my fan clutch is not good anymore too or compressor? My original compressor is discontinued, Toyota epc data show me replacing
88320-22H91
But I couldn't find any information or photo about this model, will it fit or is it 17 model?(I know here is 15, and 20 exist)

This is mine compressor

UPDATE:
Today I also tightened AC belt a little bit, was little loose.

 

[Rifleman]

I see that you're gauges are for R22 and 134A I'm not sure that you're getting an acturate reading since you're running R12. You might want to see if you can find a set of R12 gauges because the pressure scale on the face of those gauges may in fact be different then what you're using.

 

[Rifleman]

I see that you're gauges are for R22 and 134A I'm not sure that you're getting an acturate reading since you're running R12. You might want to see if you can find a set of R12 gauges because the pressure scale on the face of those gauges may in fact be different then what you're using.

Here are some photos of the gauge faces from my old R12 manifold set, and as you can see the pressure scale on a R12 gauge set will in fact be different then what you're using.

 

[smritte]

Don't worry about R-12 vs R134 gauges. Pressure is pressure. You just don't run R-12 then R-134 through the same set. The oils don't play well with each other.
The gauges I have at school need to be calibrated regularly. They don't hold up well to my students abusing them.

Cooler/hotter days effect high side more, low side slightly. Hotter= higher. Basic high side formula. Ambient (F) X 2.4 (min reading. Ambient X 2.5 (max)
100F High side gauge will read between 240 and 250. Humidity and condenser design will change this slightly. Reading is taken at 1300-1500 rpm, fan on high.

 

[1972FJ55]

This chart from Denso points to an expansion valve problem.

 

[smritte]

That's step 3 on a basic flow chart that covers most possible issues. In chart 1,2 what rpm does it say? The OP stated his readings are at idle. Warm days I can see 50 psi on the low side at idle. At proper rpm, most txv ranges are 10-30 psi. If it's over 32-35 at speed now you have a txv allowing too much flow (most automotive txv's). Once you run up the rpm, the txv restriction comes into play.

 

[Vasiliy]

Okay let's start. First test I done at morning just to see how AC works with not very hot engine after full night sitting

Outside temperature +20(68f) 38% humidity

Blower speed 1 front vent Minimum +7c(+44.6f) - +9c(+48.2f) with driving RPM 1300-1400 and NOT cycling.

After 5 min driving:
Blower speed 1 front vent At idle +10+11(+50f - +51.8f)
Inside the fridge +8+9 (+46.4f - +48.2f)
NOT cycling.

At idle with 1400rpm in 2 minute
Blower speed 1 front vent min +8+9 (+46.4f - +48.2f)NOT cycling.

 

[Vasiliy]

One hour later
+21 (69.8f) cloudy
40% humidity
Car is off Engine +63(145.4f)

 

[Vasiliy]

Stress test, I couldn't check it in 20 sec so I done in 5 minute test
Engine speed 1525-1550RPM
All blowers at MAX, fridge is ON

Compressor won't cycling, I guess because system is on MAx cooling
Front min +13+12 +11 (55.4, 53.6, 51.8)
Rear min +27+24 (80.6, 75.2)
Fridge +10+9 (50, 48.2)
Fridge evap +10 (50)
Inside car +22 (71.6 not sure, second row behind center box)

Fast RPM speed



After fast RPM speed test
At idle speed after 2- 5 minutes idling
Front min +16+18-17(60.8, 62.6, 64.4)
Rear min +21+22-19-18 (69.8, 71.6, 66.2, 64.4)
Fridge +12+13(53.6, 55.4)
Fridge evap +12+13

Engine temp +90(194)
Outside temp +22 cloudy (71.6)

 

[Vasiliy]

This video is how Fridge controls compressor at Idle, it's programmed cycling each 1 minute



Pressure while fridge is resting during 1 minute pause

Also I noticed that after 5 minutes of Hi engine speed sound came, I think fan clutch get engaged. I tried to twist the fan after I shut off the engine. it took the same force like in morning, maybe little less, but in fact no matter it was cold, or after AC , or after 20 minute test, it need the same force to move

 

[smritte]

I'm slightly confused with your gauge pictures. Just in case, this is what you need to do.
1. Hook up gauges, thermometer in center vent, ac on high fan.
2. start vehicle. If you can see gauges from inside, bring rpm to 1300-1500 (a little over idle). Watch gauges.
If you cant see from inside, pull throttle a little and watch gauges. Testing at idle does no good. Has to be at speed.
3. There is a hose that goes from compressor to firewall. This is called the suction line. Without burning yourself, see if you can touch the aluminum while its at speed. Close to firewall is best.

I need those readings.

At speed, ac on, high blower. The reading on your low gauge is, the temperature of the evaporator. If the low gauge is 32 psi, the aluminum should feel like 32 degrees. Cold.

Here's how the system works. with out getting into too much detail.

1. Fan blows through evaporator
2. The colder evaporator removes the heat from the air and the heat is transferred to the refrigerant.
3. The compressor moves the refrigerant to the condenser.
4. The condenser removes the heat and puts it into the outside air. The engine fan and or driving is what removes the heat (air flow).
5. the refrigerant returns for more heat.

The system has to be big enough to move all the heat required. 2 evaporators means more heat for the condenser to remove. The fridge adds to this also. If the condenser cant remove the heat, what is left goes back to the evaporators. You see higher vent temp. Fans on low mean less heat also. This is why we use high fan speed, more heat (stress test). Will the system remove all it was designed to remove.

Next is refrigerant. Think about it like this.
You have a small car. You drive 500km on a cool day. The car does not over heat. You add in 3 friends who weigh about 100 kilo each. More weight, more heat from engine. Car does not over heat. You drain half the coolant from the radiator. Because its a cool day the car is fine. Now it is hot out and the car starts to run hot. You refill the coolant and the car is fine driving on the hot day with your friends.
The problem was, when you drained the coolant, you didn't have enough coolant left to move the engine heat to the radiator.
This is what the refrigerant does. Too little and you don't remove enough heat, too much and you build heat.

What must be done first is determine where the problem is.
Is the problem the in the engine compartment or is it in the dash.
Stress test, are the pressures good. Is the suction line cold. If yes the problem is not the ac system. The problem is a heater valve or door adjustment. More often than not, I would have two to three problems. We fix one and retest.

Let me know what you get. 1300-1500 rpm, high fan (do front only for now), lowest low gauge and highest high gauge readings. Temp from the center vent at this time and how does the suction line feel.

 

[Vasiliy]

I hope this time I recorded good.
My Chinese adapter for high side(red cup) not good, it always hard for me to connect or disconnect it fast before freon start loose, low side is good it's 1/4 size so just 3 sec to screw on. This time I done better, was pushing at Nigh adapter and unscrewing, less loose.

This photo after full day sleep

Now stress test
Outside temp +23(73.4f)
All windows doors is closed, I was under sun. In the next video I will open driver's door and passenger window.

Low side 2.5 bar (36psi)
Nigh side 14.5 bar(210 psi)
Vent temp +12+11(53.6f 51.8f)




Driver's door open passenger window open
Low side 2 bar (29psi)
Nigh side 10.5 bar (152psi)
Vent temp +8 (46.4f)

 

[Vasiliy]

Lines

+4+5(39.2f 41f)

+41(105.8f)

+34(93.2f)