Two weeks ago, I did the Leakless gasket fix on my 6GA with success. The initial reason why I did it, aside from the obvious leaking of coolant, was because my engine temp had shot up despite the fact that I had just added coolant a few days earlier because of the leak itself. So I do the fix and all is well for the test drive and on my way to work the following work day. On my way home from work though, my engine temps shoot up. They reach 419F!! I freak out, pull over, wait a little bit but the temp never comes down and the radiator fan never turns on. I call my wife at her work and we switch cars (her work is on the way home from my work). https://photos.app.goo.gl/bdQNV8ZS3eieJ8kE8 https://photos.app.goo.gl/UU6RGg5vdiM2bxGw8 https://photos.app.goo.gl/hSwuZWK1Joqqzp9U9 https://photos.app.goo.gl/cetDKiSo86nZiWEj8 Turns out, the issue was a CEL, P0117, which is coolant sensor related. The other CEL on the screenshot is a different issue, lol. https://photos.app.goo.gl/oAmRVq7TAkc6pGLd9 So I replace the coolant sensor as well as the fan switch sensor as the radiator fan wasn't turning on when reaching 195F like it's supposed to. https://photos.app.goo.gl/8jbfJh9UedWPj4Tj7 https://photos.app.goo.gl/eXiVjKLSHpguyS8h6 I burp the system again because some coolant was lost. I do my test drive and monitor my temps. All is good. 221F was the highest it got during my test drive. https://photos.app.goo.gl/SL2fnsNw3Svtw9wr5 https://photos.app.goo.gl/pRAVppcPZKuXdJDw5 So the next day (yesterday), my drive to work is perfectly fine. I monitor temps with my Torque app and temps stay around 205-ish. The temp gauge stays exactly where it's supposed to be at, 1/3 of the way up as well. After work, I monitor my temps again, and the drive home starts off great. However, at around half way home I have this 3mi long 6% incline of a mountain to drive up. Half way up the mountain, my temp gauge starts to climb up. I look at my temps and they're going up. The hottest they got to was 239F and was bouncing back and forth between 239F and 235F for a good minute. Mind you, I had turned off the AC and turned on the heater to help control the temps and bring them back down. It's 105 out right now.... https://photos.app.goo.gl/5M4xHf7WBbjuFWym9 https://photos.app.goo.gl/x1GqeXWvn4iwTjq37 https://photos.app.goo.gl/t1DTrJr83UHhwGzE9 https://photos.app.goo.gl/eNoyPMmJpsWBrupJA Turning on the heater ended up working and brought the temps down to 231F https://photos.app.goo.gl/FE1BFgTd9LHcNzQYA https://photos.app.goo.gl/7Lh48jNsGVGRDWkYA https://photos.app.goo.gl/V4fQFW1pAbrNp27dA When my temps settled down a little bit, after the hill climb, I turn the AC back on and the temps stay below 230F. https://photos.app.goo.gl/RpoZSe8T9S2RxDVg7 https://photos.app.goo.gl/awNCC8FrBKRRipiq9 My first question is, what's going on here with my car? Is there something that I'm missing with what I've done here that would cause my car to behave this way? Is there something else wrong with my coolant system that is causing this to happen? My old coolant didn't have any muck on it so it doesn't make me think that there is any sort of blockage. A friend of mine has suggested possible head gasket issues, but the car isn't exhibiting any signs AND the J30 / J32 engines rarely - if ever - have any head gasket issues.