lol the thermostat isent just their so the car can warm up its allso their to keep the car from overheating
a thermostat can be lets say for arugments sake 74 deg c
once the temp near the thermo is 74 deg it will open untill cool water has passed it again and it close's thus heats up the radiator while the water in the engine is warming up to said 74deg the water in the radiator is allready below that and keeps repeating the cycle.
older cars with alot of corusion have a tendntcy to make the thermo stat falty my 86 vl has never had one issue with heating problems because i flush the radiator every 1000k with deminrialzed water:P but my 91 daily driver thermostat failed blew the head gasket and welsh plug and split the radiator core a few times

and still over heats cause of the head gasket.
but the heater trick works wonders
lol ill tell ya now having to remove the dizzy to remove the thermostat sux