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.
I’ve had my shop for 13 years, and I too can’t remember the last time a car came in with a stuck closed thermostat. We’ve seen many stuck open thermostats, though. Just had one last week that wouldn’t set the cat monitor due to a partially stuck open tstat.
The other thing I don’t see as often anymore is rusted out cooling systems. Mostly due to the abundance of long life HOAT coolants and the like. I’m wondering if corrosive cooling systems were the major cause of tstas sticking closed, or if modern thermostats have been designed to fail open by default similar to the old safe-t-stats, or a mix of both.