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Discussion Starter #1 (Edited)
Two issues for the longest time:

1. Leaking AC compressor (oil) only when used
2. Nice and cold are on warm nights/60-70deg days. Drive it to work in the morning, go for a spin for lunch ~90degF outside, AC blows cool air (like 60deg), not as cold as I would like.

Replaced compressor with a new one. Verified correct oil was in it as well.

Vacuumed the entire system ~28in-hg for about 1 hour, held good. Recharged system with exactly two r134a cans. Noticed low side was hitting 2.5~3 kg/cm2, high side 18-21 kg/cm2.

Spec is 1.5-2.5 low side, 14-16 high side.

So, surprised I was much higher with two cans (680g total, spec is 700g +/- 25g). I don't think it is overfilled at all.

Did the usual system checks on the AC control panel, only blinking light was the Solar sensor. All other functions worked.

This has been a nagging problem for 10 years. 10 years ago, I did replace my condensor and evaporator, so fairly new. I've heard about expansion valve being a likely culprit, although that usually creates very low Low-side pressure. I seem to have higher than normal in all cases.

Any suggestions? I'll order the expansion valve and a new receiver/dryer anyway. 22 year old system, who knows what to expect. Page AC-75 in the manual seems to be my situation, although I don't get that much sweating on the cool low-pressure pipe, but it seems to point to the expansion valve.
 

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i believe 2 pounds is too much. should be 1.5 pounds max
 

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theres a little mechanical linkage just above the passenger footwell that had become disconnected on mine, cause it to blow warm air regardless of ac setting
 

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Discussion Starter #5
Ok. Replaced expansion valve and orings. Cleaned the evaporator from outside. Using AC diagnostics, confirmed the two air doors move from one position to another (hot to cold). Also replaced receiver and orings. Keep in mind, brand new compressor.

Vacuumed the system for about an hour, 29" hg, no leaks after waiting about an hour. Charged two cans 340g each, gauges read about 2.6 and 21 (same as before). Much higher than I expected, but I filled it correctly. It is 84deg outside, air coming out of vents reads 60deg. Was expecting 50deg, but perhaps this is correct being that it is in a garage, very little cooling, and that big FMIC in front of the condenser.

Thoughts? I have a brand new pressure cuttoff switch, but haven't installed it. I assume it is working. Also, all diagnostics from the AC show no faults.
 

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Discussion Starter #7 (Edited)
Stock fan (new clutch), and stock AC #1 fan, which also turns on when AC is turned on. I do have a small kink in the large low-side line, but no more of a kink than some of the 90 deg bends. Again, held vacuum for hours, no leaks in the system.

I also monitored the evaporator with the system running, and one side gets very cold, but I noticed the other side of the evaporator towards the firewall is warmer to the touch. Perhaps I have a clog inside the evaporator coils...

And to add, I soaked the condensor with a hose while idleing, thinking this would simulate best case scenario and get my temps to go below 60degF. Nothing, stayed around 62 or so. It almost seems like some of the air is bypassing the flaps and going through the heater core. This is one that I cannot figure out...

One more item: Water Valve. Noticed the manual points to it if the outlet temperature isn't cold enough. What exactly controls this valve? And, if it shuts off coolant flow to the heater core when AC is high, could this be the problem? I have my heater hoses connected through the firewall, but reversed (didn't think it was an issue). I may try clamping them temporarily for a test.
 

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Discussion Starter #8
I went ahead and remove the two heater hoses which go through the firewall... you know those hoses which are a bitch to remove? Most folks reverse them, like I do. Well, I think I may have solved my issue, and it may explain why they need to go in the correct order in the first place.

I removed my hoses and decided to test the Water Valve (it shuts off coolant to the heater core under your dash). The way the valve works is:

- temp dial at 85degF, valve is fully open = coolant flows through the core
- temp dial at 65degF, valve fully closed = no coolant flows through the core

I reckon if you expect very cold cabin temperatures, that core needs to be blocked off. Here is how I tested the valve.

1. Remove both hoses
2. Connect some tubing to the outlet side (tube closest to driver side) and run it to a mitty-vac reservoir. Use a vacuum pump on the other end
3. Temp dial to 85degF (key = ON)
4. Run the vacuum pump. You may suck in fluid from the core, which is Ok. This is a great way to empty out your core as well.
5. Put your thumb on the inlet pipe. You should feel suction. If you cap it, the vacuum pump should struggle.
6. Move temp dial to 65degF (this closes the water valve)
7. The vacuum pump should start struggling. This confirms the water valve is sealing. (Note: If you attached the vacuum to the inlet port - passenger side port - you would never get vacuum with valve closed/open. I assume this is the nature of the valve).

TestingWaterValve.jpg

I tested mine, and it seemed to work correctly. In theory, because I had the heater hoses reversed, even with the water valve closed, hot coolant was still within the heater core.

By having the heater hoses on correctly, the water valve would stop hot coolant from entering the core right at the onset. In fact, if you keep the dial at 65degF, when you start up your car on a hot day, hot coolant never enters the heater core. Thus, your AC should cool more efficiently right off the bat.

It's 75degF outside, and my air vent temps dropped to 50. That is a good sign, but I need to retest when it is 85 again to confirm this fixed it.

If this doesn't work, I'll throw my hands up. :wavey:
 

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Discussion Starter #11
Yes. Was 85degF yesterday, started her up from the "cool" garage, drove about 15 minutes to a destination, air temp reached down to 50degF (much better). Had 1hr lunch, left windows closed to get some heat in the cabin. Back in the car, through some traffic lights, wouldn't get down below 60degF, but still cooler and dryer than before. But, as soon as I got on some mixed highway, saw the needle drop to 58 and moving further. It is obviously performing better than before, and quite frankly, I think this is as good as it gets.

I can tell swapping the heater hoses back to original location worked since after a drive, I could feel both hoses were much cooler to the touch since no coolant is actually flowing through the internal heater core.

After reading another thread on here of why "Anyone else have insanely cold A/C?", blowing frost out the vents like a freezer, I cannot figure out any other way to reach that level, especially when majority of the AC parts are brand new at the moment. In fact, I've been in newer vehicles who's AC just never gets freezing cold, not until you start moving at highway speeds...

About the last thing I can think of is sealing up the vents a bit more, and possibly replacing one of the slightly-kinked low-side lines, although this may provide minimal benefit. BTW, those lines are discontinued from what I'm told :(
 

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If you have the blower on lowest setting does the compressor clutch cycle at all? If it's only getting down to 60 the compressor shouldn't cycle. If it's not hitting its target temp it keeps on running. You may have a bad evap thermistor
 

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thanks for sharing your experience ... I'll use your methods to trouble-shoot more.

I've experience the same problem for 10 years also ... changed evap & expansion valve but not the compressor. Have the stock fan and helper ... I'll look into the water valve and linkage.
 

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Discussion Starter #15
If you have the blower on lowest setting does the compressor clutch cycle at all? If it's only getting down to 60 the compressor shouldn't cycle. If it's not hitting its target temp it keeps on running. You may have a bad evap thermistor
Clutch doesn't cycle, always running. If I had a bad evap thermistor (open or short), the AC diagnostics would catch it. If I had a "bad" sensor, worst that I believe would happen is the AC compressor would start cycling to keep the evaporator from freezing. I don't see or hear the compressor cycling.
 

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You're not getting to target temp. You know that already from your 60 degree lowest temp
 

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I had something similar happened to old Mercedes years ago, turn out to be the control module.

Not sure if it could be related, but given that we have a manual climate control, could that be potentially sending a bad signal to keep the temps above than normal?
 

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Discussion Starter #18
You're not getting to target temp. You know that already from your 60 degree lowest temp
If I'm asking for "as cold as possible" by placing dial at 65degF, the AC should have:
- blend door blocking the heater core (which I verified)
- heater core water valve shut (which I verified)
- compressor on continuously (which I verified)

As for a bad control module, our modules do have diagnostics capability. Now, let say it is bad in a strange way, the only way it could force keeping temps above normal is by:
- cycling the compressor (not happening)
- moving the blend door (stays shut for cold air only), which also moves the water valve since they are mechanically linked
- reduce blower speed (not happening)

Since I'm not using the AUTO function, all the other closed feedback doesn't come into play. I thought about replacing the AC control module/amplifier, but I just can't find anything wrong with it.

Let's say the evaporator temp sensor is flaky and is signaling a "freezing" evaporator, the AC control unit has no choice to be cycle the compressor to stop the evaporator from cooling. Since that isn't happening, I am assuming the temp sensor is fine.

The one odd ball here is that with just one can of R134a, I can get my low and highside pressures to reach normal specifications. It is odd since I thought it needed two cans (700g) to get there, but with 2 cans, I start exceeding the pressures. Wonder if that indicates a blockage in the system? Tubing and condenser are about the only things I have not replaced recently. Actually, I've read that blockage would cause a REDUCTION in pressures, so this is something else...
 
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