Overheating when air recirculation is engaged?

[ansubi]

Hi all,
I'm just trying to figure out an overheating issue I'm having with my 2011 Subaru legacy...started overheating while running the a/c. Did a flush, replaced thermostat coolant and hoses, burped the system several times, everything seemed good. then today while driving, I noticed it started to overheat again only after I had tried to turn on the air recirculation inside the cab. I parked at a store, turned it off and let it cool. Topped off the coolant and started it back up. Ran the a/c on my drive home (about 20 mins, but also sat with the a/c on at idle for 10 mins before driving back) and had no issues. I got home and decided to double check my theory, turned the a/c off then turned on the air recirculation and it immediately start heating up. Oddly, even once I turned the recirculation off it continued to heat up...until I tried turning the a/c back on after which it promptly dropped back to normal temps. For now I'm planning to just not use the air recirculation but I'm honestly stumped as to how this alone could be causing an overheating issue. Just wondering if anyone had any thoughts on what might be happening here.

I've also noticed when it starts to overheat the heat in the car doesn't work unless I maintain high rpms, which leads me to think it's causing a flow issue, but again I'm stumped as to why the air recirculating button is causing this to happen. Esp as it seems to run fine as long as I don't use the recirculating setting.

Any help would be really appreciated, for now I'm just not going to use the recirculation but I'd love an answer as to why this is happening.

Thanks!

 

[Dick Foster]

An enigma. It sounds as if it's exactly backwards from what one would normally expect.
Using recirc, the AC is cooling pre cooled cabin air which is normally cooler than ambient air. That is, unless it's winter.

 

[ansubi]

Yeah it's very odd. A quick update. I replaced the radiator. Had no issues since...until today when I figured I'd try to run the recirc again...and started to overheat. I managed to catch it and get the car cooled again before it overheated but it got up to 231 before dropping and has been climbing intermittently since even with recirculation turned off. It settled back to normal after a couple hours. It def seems related to the recirc. It seems like it causes a flow issue after somehow...my only theory is it's shorting somewhere and causing the coolant to be charged? And maybe thats causing the minerals in the coolant to solidify and clog? It seems a little far fetched but I'm honestly stumped at this point.