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09 Legacy GT, 08 Legacy 2.5i, 09 Outback 2.5i
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Discussion Starter #1
In my son's 09 OB 2.5i the air conditioning appears to not work or not work very well at all. I've added a bit of R134a to it with an old test gauge fill kit that I do not trust the gauge on at all. It reads a bit on the high zone when connected to the low pressure side fitting. The compressor clutch cycles on and off every ten seconds but when it flips to on it is off again in ~1 second. Unsure if that means low or high charge or something else completely.
 

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2005 Legacy GT wagon 5MT Limited
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Step 1 is buy or borrow a gauge manifold and see what sort of pressure you actually have.
 

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09 Legacy GT, 08 Legacy 2.5i, 09 Outback 2.5i
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Discussion Starter #5
Is there any guide as to measure the pressures? I do have a new and (I think) workable AC pressure gauge set. Do I measure just the low side first or both low and high? Also unsure if I need to be looking at the gauge readings labeled "r134a" or the one labeled "kg/cm2".
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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This topic was covered just within the last few days on here. So, you might try to find that discussion, it would be helpful to you.

You have the tools to diagnose what's going on within the AC system there.

Generally, the low side should be nearly equal to the high side when the system is off.

Running and engaged, the low side should not go below 27 psi (that's the cutout pressure)

The high side will run at around 200 psi, especially in hot temps.

You need to run the engine at about 1200 rpm to get a good reading on your gauges.

DO NOT open the high side valve on the gauge set! Only open the high side valve at the end of the hose where the quick connect is located!

Give this a shot and report back with your data.
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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Here's a link to a discussion that may help:

Subaru Outback - Subaru Outback Forums > General > Problems & Maintenance > Air Conditioner problem!!
 

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09 Legacy GT, 08 Legacy 2.5i, 09 Outback 2.5i
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Discussion Starter #8
After hooking up the gauge set the AC appears to work a bit better. Maybe it was bit a bit overcharged? After a 15 minute drive here are the pressures - two pics. To me the low pressure seems maybe on the high side??
 

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After hooking up the gauge set the AC appears to work a bit better. Maybe it was bit a bit overcharged? After a 15 minute drive here are the pressures - two pics. To me the low pressure seems maybe on the high side??
Those look pretty good to me.
You get a better reading if the engine is at about 1000 - 1200 rpm. That really makes the low side more responsive.
Where are the gauges reading with the system shut down? They should be close to even.
I would consider 40 psi high on the low side with the system running. Of course, when it's cycling you should see it drop to around 27 or so before it cuts out.

I'm sure there are others on here who are more versed than me.....I'm still learning!
 

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Discussion Starter #10
Those pics were at about 1500 rpms. I think low pressure is a bit high. This compressor has ~213,000 miles on it so maybe it is a bit on the weak side. I also wondered about when this rig was down for ~4 weeks needing a new engine and the compressor was lying upside down so as to be out of the way Might this cause the compressor oil to move elsewhere?
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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Those pics were at about 1500 rpms. I think low pressure is a bit high. This compressor has ~213,000 miles on it so maybe it is a bit on the weak side. I also wondered about when this rig was down for ~4 weeks needing a new engine and the compressor was lying upside down so as to be out of the way Might this cause the compressor oil to move elsewhere?
Yes the oil in the compressor could have ran into the line and then into the desiccant bag inside the tube on the side of the condenser (well, that's where mine is located) I was able to unscrew the nylon cap on the bottom of that tube and remove the bag. It was soaked with oil! I found Oreillys had a replacement for around $20. You want to replace the oil in the compressor.

That will cause the system to have problems with cooling and pressures.
 

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09 Legacy GT, 08 Legacy 2.5i, 09 Outback 2.5i
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Discussion Starter #12
Yes the oil in the compressor could have ran into the line and then into the desiccant bag inside the tube on the side of the condenser (well, that's where mine is located) I was able to unscrew the nylon cap on the bottom of that tube and remove the bag. It was soaked with oil! I found Oreillys had a replacement for around $20. You want to replace the oil in the compressor.

That will cause the system to have problems with cooling and pressures.
I feel we are onto something here... I am trying to find this desiccant filter but there is not a tube obvious where it might be. The high side of the compressor connects to the driver side of the condenser and I see nothing that would indicate a drain fitting for a desiccant bag or similar. Am I looking at the wrong spot?
 

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2005 Outback R LL Bean 3.0 H6 w/ 5 speed sport shift
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I feel we are onto something here... I am trying to find this desiccant filter but there is not a tube obvious where it might be. The high side of the compressor connects to the driver side of the condenser and I see nothing that would indicate a drain fitting for a desiccant bag or similar. Am I looking at the wrong spot?
my dryer is on the passenger side of the condenser and is made onto the side in an upright position. The cap is accessed from the bottom. I think you'll have to remove the brackets that hold the radiator and condenser so you can tip the radiator back for access....or just disconnect the AC lines and pull the condenser - that's probably the easiest way to go.

I'm not certain your model has this exact configuration? Seems this changed within the Gen 3's........

Once you replace the descant bag and get everything hooked back up, you should pull the max vacuum you can and hold it there for several hours to pull any moisture out of the system before charging.

My system takes 2 cans to fill from empty.
 

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I pointed the pen at the location. The new condenser is $55 so you may be better off to just replace the entire unit rather than spend $25 on the bag!

I used my air compressor to blow all my hoses and get any oil out of the core in the dash before buttoning it all back up. You probably should get the o-rings where the compressor hoses connect and replace those at this point to. You will probably have some residual PAG oil in the compressor so don't use the total amount recommended for a new compressor.
 

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Discussion Starter #15
Good deal. I ordered the new condenser unit along with some compressor oil, a vacuum pump, and the valve/fitting for the 134a can. We've not opened it up yet since it is working alright at freeway speeds. The AC was ice cold prior to the engine replacement project that took ~4 weeks where the compressor was upside down.
 

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09 Legacy GT, 08 Legacy 2.5i, 09 Outback 2.5i
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Discussion Starter #16
I believe I have everything on hand to work on the AC here. New condenser, refrig oil, manifold gauge set, vacuum pump, and r134a cap tap fitting. Are there any good how-to guides for a home handyman on the procedure? We are planning on replacing the o-rings on all the joints on the compressor and the condenser. Biggest unknown is how to know how much oil to add back into the compressor if part of the oil is still in the compressor or elsewhere in the system now.
 

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I was always taught 2oz of oil with a new compressor now this was when working on large scale items like semis and construction equipment, so I’m not sure if I would put that much on a smaller car unless it had rear AC as well with more hose length and a second evaporator.


Sent from my iPhone using Tapatalk
 

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Discussion Starter #18
AC is back up in my son's Outback now. Replaced the compressor (used) and a new condenser. Hard part was to know how much oil to put back in the compressor. Added maybe 2oz of PAG46 to it and it seems to work awesome now.
 
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