I can see the Ad for those trucks now...."Even comes equipped with cardboard on the radiator at NO extra charge".
Friction causes heat. If the engine is worn bad it is going to take longer to heat up the coolant.
Engines were designned to operate at a set temperature..the thermostat controls that providing that the rest of the cooling system is in working order.
Reversing the heater hoses may cause the heater to not work properly too. They are designed to flow in one direction.
