Coolant issue
So just today I had my coolant temp needle go past the middle and I knew something was up as it kept climbing. Luckily it didnt go near the super hot zone as I pulled into a sprouts parking lot. Freaking out I checked the overflow tank only to see my coolant completely empty. Of course I was looking for signs of valley plate leak or a water pump leak but nothing. I bought some distilled water and filled up the radiator TEMPORARILY and aired the system out. Luckily there was some pink coolant left in the system as well. I drove around and temps held steady for around 10 miles of driving and some highway driving. I check the fluid level again and its sadly empty. I see no leaks anywhere and left it in the parking lot for an hour or two to see if it leaked anywhere and nothing sadly. Im assuming its the radiator cap since that has NEVER been replaced and it slightly crusty. What yall think because im stumped unless this radiator cap comes in and fixes my issue.