As I've mentioned before it's not just the quoted thermostat temperature that affects the thermo dynamics in engine cooling systems its the hysteresis as well. I was once given an 80°C thermostat to replace a 72°C one fitted to a vintage diesel in a narrowboat, to cure an overheating issue. This worked because the stat started opening at 65°C. It didn't help that the high flow seawater pump had been retained for originality and was pushing coolant through the closed circuit skin tank so quickly it didn't allow enough time to dissipate the heat.
Modern cars often use ECU controlled coolant thermostats. They operate a tiny heater in the stats wax chamber that quickly opens same to be ahead of the game when there is a sudden high demand placed on engine.
