Thermostat OEM Nissan or AISIN

replaced the thermostat with a factory Nissan OEM thermostat. Completely fixed the problem..

yes the part was OEM from nissan

I’ve had so many replacements fail in all my Nissans over the years that I just get an oem one from a dealer. Never had an oem one shit out yet.

Hard to say if it’s directly OE to Subaru, but I use Aisin thermostats and water pumps on every Subaru engine I do, they function the exact same and are equally as reliable as the original equipment, not to mention these thermostats are $15 on amazon compared to $40 from Subaru.

Since going with the OEM thermostat, my temp gauge has stayed pinned just below the middle of the gauge, even towing campers and heavy loads on hot days.

After doing some research I found that AISIN is likely the supplier for the Subaru OEM thermostats so I ordered them off of Amazon (sold and shipped by Amazon) and they appear to be just that. They were close to the same price and are made in Japan. AISIN THF-007/009 appear to be true OEM Subaru thermostats for FB20B

Only an OEM Thermostat fixed it.

Pick up the AISIN OEM version of your thermostat. It's pretty cheap so no reason not to get the best one instead of some cheaper alternative. Also you can test the function of your thermostat before doing the change by putting it in hot water. You can check the specs of the one you use, but for the AISIN one for my 2012 civic (9th gen), the thermostat starts opening at 170 and is fully open at 190.

New thermostat (Aisin brand), fresh oil, fresh coolant, replaced at that time. Coolant system bled well. No leaks. Heat worked flawlessly. AC worked after the swap. Overheated the drive home after that swap, turns out the radiator fan module got fried on the final drive (it was above 250 on coolant temps before replacing the engine, on a 30 minute, fast, highway drive). Ordered a new one. Everything working perfect now at the right temperature points. Engine times reading perfect too (watching live data). On a 30 minute highway drive tonight, returning home after the same drive 2 days ago with zero issues, it overheats again. Radiator fans are working. The one thing I changed during the drive was turning down the heat from HIGH to 75. No more than 10 minutes later I hear the bubbling in the heater core area. Take my exit from the highway, and the red temp light starts flashing, temps read 239, and the bubbling worsened. Temps stayed above 228 until I made it home from my exit. Worse at red lights. Turned off for 10 minutes, turned back on, temps went up to 232 at idle, holding steady. Lower radiator hose read 102 degrees, upper hose reads 190.

I recently changed my thermostat due to my temp gauge occasionally dancing. The old thermostat appears to be bypassed as theres no actual thermostat in the housing. After putting on a new nissan one and oem gasket i bled the system with a overflow funnel for about 40 minutes until i stopped seeing bubble. Also using peak 50/50. Afterwards my overheating problem has gotten worse i overheat in about 10 minutes. I tried bleeding again and same results.