Hey guys, i seem to have a lot of questions on my mind today. Come spring time (only god knows when that will be) i want to flush my cooling system out and refill it with fresh coolant. Iv got a Haynes Diesel Repair Manual to help me out in the process but i still have a question. The question is during one of the processes in the manual it says to drain the coolant out of the block, well thats good to get the old coolant out but when you start putting coolent back in the system the only place its going to fill is the radiator and not the engine, right???? I guess what im trying to say is how can coolent get into the engine when the engine is cold. Even when you go to start it up with that thermostat closed you are not getting any circulation or coolant and with nothing but air in the engine block how does that thermostat open with no coolant behind it to heat it up. Im just afraid that when i refill the ratiator that no coolant will get to the engine because of the thermostat being closed and when i go to start it up it will overheat because the thermostat wont open because theirs no coolant behind it to open it.


Am i over thinking the situation or am i right. How does the coolant get back to the block when you refill the system without starting the engine???

Also is there any difference in Motorcraft thermostats ans Thermostats sold at napa, it says in my book not to use anything other than a Motorcraft E5TZ-8575-C or Navistar 1807945-C1 or equivalent???????

 

The engine and radiator are placed so gravity allows the coolant to drain to the low spots.

Also near the thermostat or on it is a small orifice or even a notch on the seat allowing a small amount of fluid to pass ... just a few percent of 100% flow rate to allow some circulation so heat is distributed throughout the coolant AND heat up the thermostat so it will operate.