I’m not a car guy. I want to be. I’m learning. I learn by making friends with mechanics and absorbing their information. I had a car a few months ago with some overheating issues. (Got it resolved. No water in my coolant at all, using straight concentrate in a brand new, empty radiator, like a dingus. 🤦🏼♂️) But before I fixed it, someone said it might have been the thermostat. I asked a mechanic friend of mine about it. (I haven’t known him long.) He told me he’s been a mechanic for right around a decade and has NEVER seen a thermostat issue cause overheating. Is he just totally out of touch? Or did I misunderstand how the cooling system of a vehicle works? Let me know.
Stuck closed thermostats are very rare and difficult to diagnose. Any “shade tree mechanics” on here claiming otherwise probably misdiagnosed or accidentally solved the real problem which was low coolant or something that would have been taken care of during replacement.
It’s not super difficult if you have some sort of temperature gun. Take measurements on the hoses and block to see if coolant is circulating.