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Discussion Starter · #1 ·
I have a 2014 Subaru outback 3.6 and my ac is being a pita gauges are at 150 and 70 to 80 ish so vacuum and everything is good evac the system recharged it couldn't find a leak... The one thing I noticed is the compressor clutch never stops spinning even if I turn the ac off from inside the of the cabin... Anyone ever experience this?
 

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Outback 2011 3.6R Premium
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That model has a variable displacement compressor which is “always on” so what you are seeing is normal.

The vehicle ECU controls the compressor.

Seagrass
 
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Discussion Starter · #3 ·
That model has a variable displacement compressor which is “always on” so what you are seeing is normal.

The vehicle ECU controls the compressor.

Seagrass
So what do you think the issue might be could it be a bad relay or something? Because it will blow cold and when it does it blows ice cold and then will get warm and then cycle back to cold again..
 

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Discussion Starter · #4 ·
So what do you think the issue might be could it be a bad relay or something? Because it will blow cold and when it does it blows ice cold and then will get warm and then cycle back to cold again..
And would the clutch still spin even if the ac is in the off position?
 

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Yes the clutch always spins (there actually is no clutch).

How much refrigerant did you put in the system? From memory the charge is 400 to 450 grams.

The High pressure looks to be too low, from memory it should be around 220 to 250.

At a guess, if you have the correct charge in the system, your compressor is failing.

Seagrass
 
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How much refrigerant di you put in the system? From memory the charge is 400 to 450 grams.

The High pressure looks to be too low, from memory it should be around 220 to 250.

At a guess, if you have the correct charge in the system, your compressor is failing.

Seagrass
I put 12 to 14 oz and it says it holds about 14.5
 

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The symptoms you have can be caused by a low refrigerant charge.

The 2011 3.6 I own says the charge is 400 to 450 grams (14 to 16 ounces) so it might be worthwhile adding an extra couple of ounces to see if that fixes the problem.

My vehicle has travelled almost 150,000 miles and I just had to replace the compressor as it was failing.

Seagrass
 

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Discussion Starter · #8 ·
The symptoms you have can be caused by a low refrigerant charge.

The 2011 3.6 I own says the charge is 400 to 450 grams (14 to 16 ounces) so it might be worthwhile adding an extra couple of ounces to see if that fixes the problem.

My vehicle has travelled almost 150,000 miles and I just had to replace the compressor as it was failing.

Seagrass
Man I really hope mine isnt failing I will hook it up to my gauges again when I get off work here in a few hrs I havent priced a compressor out yet I fix all of my cars myself if I can. 🤞🏻 I will let you know how it turns out though
 

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Man I really hope mine isnt failing I will hook it up to my gauges again when I get off work here in a few hrs I havent priced a compressor out yet I fix all of my cars myself if I can. 🤞🏻 I will let you know how it turns out though
The compressor runs between $650 - $700, approximately. If it is actually failing, you'll want to check for metal shavings in the system, or just to be on the safe side, possibly replace the dryer, evaporator, and condenser. You don't want to have metal shavings get into the new compressor, lest it fail again.
 

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most likely point of failure is the pressure switch on the compressor. used in the 3.6L

min utilization is 2% for Subaru variable compressor.

if your low side pressure is high and high side low as you have indicated:

I would be looking at your expansion valve after you verify proper charge level as it could be over charged
 

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Given the pressure you posted, the compressor is moving refrigerant, just not enough to be effective. If the compressor is not making noise it is most likely the variable control valve on the compressor that is not working. Your intermittent cold, warm, cold points to the same thing. The valve is hanging up either due to a weak winding or corrosion on the valve is a restriction. Another possibility is you have bad grounding from the battery and the system, along with others on the car, is not getting sufficient current flow to operate.

If you evacuated the system down to a vacuum and charged it with 14 oz, then it's not a volume issue. And on volume, too much refrigerant will cause similar values as you posted except the high pressure side would be closer to 200 and this is because the system is too full and the refrigerant can't move due to volumetric restriction.

It is not the expansion valve. If the expansion valve were bad the high side pressure would climb fast and the compressor's valve would be constantly opening and closing to control flow and pressure. On the flip side, the low pressure would drop really fast and the vavle would again be working to control flow and pressure and you would see the low side go up and down in pressure fast in the same fashion as if the system were about 1/2 full.

As for replacement compressors, here's a few options. Try to match the part number on your current compressor. And while you have the system empty and taken apart, change all the line o-rings and the two service port Schrader valves. You can get a "kit" from your local part store. You'll need a small pic and a tire valve stem tool.





 

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If you have access to a scan tool that sees HVAC data either from the HVAC control module or the ECM, you can see the valve commands in the data. If the computer is commanding the valve to 100% and the low side is not down to 40-50 psi, but still holding up around the 70 mark, then you know it's a circulation issue most likely with the valve. It could be wear internally, but the most common is the valve.
 

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What @cardoc said is good info.

You need to test the system under varying conditions when you know the correct weight of refrigerant is in the system.

You want to first know the ambient temps and then test when the vehicle is cold and the interior cabin is hot. This will kick the ac on 100% cycle and you can then check pressures. Your suction pressure needs to be much lower then 70 or 80psi for it to be cold. Most vehicles will he around 35-45 psi on r134 but that depends on ambient temps and humidity. The vehicle repair manual will give you specs.

As a rule of thumb, you typically want the high pressure reading to be above 200 psi when ambient temps are above the high 80's. Every car will vary a bit.

Depending on how the pressures act as well as vent air temp you can then narrow down the issue.
 
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