In DD's book he talks about running water only during the first start up after a complete rebuild to "sweep out" the cooling system. Should I pull the thermostat, run it for a few miles, and then just pull the bottom hose to get this done? Should I coordinate this with the initial 50 mile oil change? Thank you!! G

I would use a thermostat, so the engine warms up and has the same heat distribution as normal. Thermostat's are very helpful in proper heat management within the engine.

I would not leave water in it for very long, as it will begin rusting the water jacket.. so if you put 50 miles on it in a day or weekend, then do the oil change and then install the antifreeze. Any longer than that, and I would flush/drain and refill before you get to the 50 mile mark.

Remember there is a pipe plug that drains the block cooling system at the left rear, Remove that and you will get more water out than just pulling the lower radiator hose.

The way it is right now, there is no water in the block, no water in the head, and I was thinking about pulling the thermostat at first startup to fill it up. I believe in using a thermostat for heat management, I am just nervous about waiting for the thermo to open to get that started. G

It may also be a good idea to put a piece of screen over the radiator inlet before you put the hose on to prevent any junk getting down in your radiator. They also make special inline coolant filters too.

D

You don’t need to wait for the thermostat to open for water to circulate through the block and head. There is an external bypass hose that connects the cylinder head to the water pump. So when the engine is running there is coolant flow out of the head to the water pump and into the block. The only item that is bypassed is the radiator.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

I'm afraid I looked at the cooling system as going from the rad, out the top hose, and getting stopped by the t-stat before getting to the engine to fill it. When I stopped and surveyed where the pump is , at the end of the bottom hose, and that it pumps into the block, through the head and is stopped from going to the rad by the t-stat, I realized that I didn't have to worry about coolant at startup. I just need to go down to the local high school and sign up for auto shop....again (fifty years later)! Pretty basic!! G

I don't get any of this. First, you want the engine to start and get up to temp. No thermostat will not allow it to reach full temp....that's not good.

Second....if an engine is rebuilt (properly), why would the cooling system have junk in it?