AC in another vehicle

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William_ff

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I replaced the AC compressor in the 2008 Expedition over a year ago and everything went well and is still looking good and very cold.

I have a 2004 Thunderbird that the AC hasn't worked for a very long time ago. I started with the clutch fuse and found it blown and replaced it. I then hooked up the pressure gauges and found no pressure. I hooked the ac vacuum pump to it for about 2 hours total high and low side. Is it odd that both the high and the low side seemed to have separate vacuums? With me being unsure of the total oil remaining in the system, I let the system suck in 3 ounces of PAG 46. It calls for 7 ounces. I then put in 3 ounces of the 134 A with stop leak and then started on the first 12 ounce can of 134 A. It is over 90 F now. After it wasn't taking any more, I turned on the car and the AC. I didn't get the full can in yet and the system calls for a total of 28 ounces. So I am about half of that. The high side I think is getting to 160 PSI and the low 90. After some time it was a bit more even like 130 PSI. I took off all of the gauges and the low port is next to the compressor and is very very hot. I could barely take off the hose because of it.

Does this sound like the compressor? Do these symptoms point to anything else like the expansion valve?
 
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William_ff

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One more thing. The valve is in the dashboard and when I turn the AC on, I can hear hissing from it until I turn it off.
 

stamp11127

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You've created additional problems using the ac stop leak. The txv may be stuck in the wrong position.
If you didn't swap any components there isn't a need to add oil. It reduces the amount of space available for the refrigerant.
You will have the same amount of vacuum on the low and high sides when pulling a vacuum.
Hissing from the valve is a vacuum leak.
The low side pressure is too high and the high side is too low for the ambient temp of 90.
To do this right it should be put back to factory specs. Drain all the oil, flush all lines and components, replace the service ports. Refill the compressor will oil keeping track of the amount. Add 1 oz of oil to each component but not go over the total amount for the system.
Pull a 30 min vac and see if it holds. If it does then vac for another 2 hrs. The deeper the vac the more moisture will be removed.
Charge the system to 80% of full charge. Run the system and let it stabilize. Record pressures, low should be just above 32. High will run 200-225. Add as necessary. If you are close to 250 on the high make sure there is enough airflow through the condensor. If they are similar to what you are reading now, test the txv by chilling the bulb and observing the pressure change with the system running.
Once you are at this point the pressures will tell you how well the compressor and txv are working.
 
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William_ff

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I wonder if there is something else with this system. I tried to read the static pressure and it was no reading on the low and (sorry not exact) I think 100 on the high side. I then turned on the AC heard the hissing and the low side was at about 80 and high up to 150.

I did everything you stated besides adding the oil. The TXV requires me removing the dash, heater core, and maybe some other stuff...
 
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William_ff

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Is there something that might close up the low port? I think I need a special tool to read and service the low side port. It just doesn't act right. I am reading that if you see no reading on the low side you may need the dealership to do this.
 

stamp11127

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The txv is a variable orifice that will meter the refrigerant into the evaporator based on the evaporators temperature. If it sticks where it is too restrictive, the high side pressure will blow past the normal readings. I pulled a gauge set off once when the high side pressure was passing 420psi, low side was pulling a vacuum.

A low side reading of 0 can indicate the valve on the service port isn't opening.

The txv should be located right up against the firewall where the lines go into the evap.

There is a tool to remove the valve on the service port depending on the type of port. Some just unscrew and others need a core removal tool.

Use dealerships as a last resort.
 
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William_ff

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After some troubleshooting with the gauges, I found the problem was that the hose was too tight and closed up the hole. After I fixed that I was able to finish filling up the system and I have full cold. So cold it was fogging up the windshield :)

Thanks for the help!
 

1955moose

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Let me wrap my head around this. The problem was you tightened the fittings on the R134 gauges too tight on the service ports, and that's why the freon wouldn't enter the system? How is that even possible? Your supposed to hand tighten the fittings only. Do you have a 500 pound gorilla as a mechanic apprentice? And Everytime I think I've heard it all, something like this happens!

Sent from my N9131 using Tapatalk
 

stamp11127

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Well, we know what really happened, so we'll just leave it at that and move on......

Bedrck47 is still with us - I just didn't hit "enter".
 
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William_ff

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It was actually very easy. I had to just barely tighten them where there was no leak in it in order for the gasket not to collapse. These are the heavy duty gauges that you can rent from AutoZone as well. I've used similar ones in the past with no problems. All good though. So cold this morning, I had to turn it off :) I've been without AC on my Thunderbird for like 6 years.
 
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