2004 Subaru Outback Intermittent A/C after car reaches operating temp...
Intermittent A/C after car reaches operating temp...
What is your question?
2004 Outback Limited, purchased used in 2014 w/107,000 miles, currently with 134,588. A/C clutch started to fail, Fall of 2015, and eventually froze. Replaced A/C compressor unit with a Used unit, Spring 2016.
What has been done: 1) Used a/c compressor unit installed. 2) Full evac of a/c system. 3) Leak test - passed (-25 atm held for 45 mins) 4) Refill with coolant using 2oz red dye, 3oz oil & 17oz R134a.
System runs smoothly, clutch engaging, cold air blowing for the first 15-40 minutes at idle, then it goes warm. If I turn a/c off for a few minutes and turn back on, will blow cold again for about 1 minute. This was happening when the outside air temp was in the 60's, below 80's (not sure if it's relevant?). When the outside air temp was 89degrees and the car was up to temp, a/c wouldn't blow, clutch wouldn't engage. I've swapped A/C and Blower relays, same results. I installed new A/C Expansion Valve and A/C Receiver Drier too. Clutch gap...is @.27mm -.3mm
Is there some kind of a/c temp/thermistor sensor that I missed? Ready to pull my hair out!!!
Any help would be greatly appreciated - Mel
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I have concern about your system pressures -- have you measured the high and low side pressures? A restriction in the system would shut your system down due to high pressures; the expansion valve in the evaporator could be prematurely shutting off the compressor, and the cycle switch could have something to do with it. All guesswork from here, but a few places to look at. Good luck.
Ran a/c this morning on the way to drop kids off, it stopped blowing cold after 15 mins of driving...will check pressure today, and update! Thanks Dave
Follow up:
Checked cabin air filter, very little debri. Attached pressure manifold and got this reading with car Not running: 88 degree ambient air temp - Low 115 psi - High 125 psi
Is that a stuck valve somewhere, if so where?
Hi Casey, thanks for chiming in! I did check pressure with car running, with little to no deviation...H 180 psi and L 110 psi. But, here's the kicker. After letting the car sit for about 45 mins, started it and put A/C full blast, col Cold AIR for 30 minutes straight. I eventually turned it off. Again, the car was just sitting on the driveway, ambient air was 90 degrees!
If it's capable of doing that for 30 minutes, something is disrupting my enjoyment of the C O L D, what???
I think the A/C is fine, but there may be an issue with the connector for the compressor clutch, high pressure or low pressure sensor, or even the A/C switch on the control panel. The relay is also suspect.
With the vehicle sitting still (no air over the condenser besides the fan), that is the most difficult time for an A/C to function properly. So I wonder...
If you get the A/C to run constantly in the driveway, does it stop when you drive, hit bumps, turn the steering wheel, or other normal operations? Does the A/C light blink when it stops working? With the A/C running while parked, does shaking the wires for all electrical components make the A/C turn off?
The A/C button turns the relay on, the relay sends power to and engages the A/C compressor clutch. If you get a blinking button, look at the compressor clutch to see if it is spinning.
If the clutch is spinning, and you only get ambient temperature air, check if you have one A/C line that stays hot, and one that stays cold.
I'm also slightly concerned that the clutch is not fully engaging, and spinning the engine to higher RPM is causing slippage...
This is an odd one.
You brought up some good points to consider Casey! I went to a local and reputable garage yesterday for some Q&A. They recalled a customer - 02 Impreza with exact same symptoms, the repair record indicated replacing the Thermistor just behind the cabin air filter location. Without doing full diagnostics, they couldn't guarantee that it is the same solution for me.
This morning, I cut and installed new spade connectors to the compressor clutch (they looked suspect). Ambient air is only 60 today. I ran a few errands with a/c running, (approx15 minutes), but had no issues whatsoever. As per dash A/C buttons, it does not blink when it stops functioning. When it does stop, usually, the clutch is no longer spinning...I've never noticed the clutch spinning and not blowing some cool air!
Excellent! If the A/C button is not blinking that means the compressor is not being shut off due to recognized error. That means the vehicle thinks the A/C should be off, or it thinks the compressor is still on. I think you're on the right track replacing the connections to the compressor clutch, and I wouldn't be surprised if it remains functional.
Lastly, if it does stop blowing cold, and the compressor clutch stops, pull the relay for the compressor. If it clicks, the compressor should be on, if it doesn't click, the switch in the cabin may have a bad connection.
Ran a/c this morning on the way to drop kids off, it stopped blowing cold after 15 mins of driving...will check pressure today, and update! Thanks Dave Follow up: Checked cabin air filter, very little debri. Attached pressure manifold and got this reading with car Not running: 88 degree ambient air temp - Low 115 psi - High 125 psi Is that a stuck valve somewhere, if so where?