The Stovebolt Site Forums The Shop Area Engine Shop 1941 216, Thermostat question, may have made a rookie mistake

I have a 1941 Master Deluxe (yes I know it is a car but after looking at other forums I am going to where the best place to go for advice on these motors is).
Question #1:
I and my sons are putting it back together. After installing a new water pump I installed a new thermostat. Not sure if I put the right end up. I placed the spring down and bolted it back together. Then I thought well that does not seem right.

Question #2:
We have run the motor but not for more than 20 minutes at idle. The heater hose is looped back to the pump, the heater core leaks. It got up to temp and never overheated. The top and bottom hoses where warm. We did discover that unlike a modern car with an overflow tank on this it is good to fill the radiator to the top, the overflow tube works. So with an unpressurized system like this how high should the radiator be filled? What is the proper way to get any air out of the system on this car? I am used to wait for the air to stop coming out the top but is this the same method for this one?

Yes, The pellet & spring go down. Fill the rad. to about2 in. bellow the top when cold. The coolant expands when it warms up & will be a little bellow the top. If you need to vent the system loosen the heater hose from the therm houseing & let the air out till coolant comes out. You probably will not have to vent it though. The top hose should be warmer then the lower hose & you should only be able to hold on to it for 2-3 seconds. The heater hose should be hot as well.
George

It will puke out what it doesn't want even if it is a pressurized system just make sure you can see it above the radiator tubes after it cools

If you drill a small hole in the thermostat it will purge the air as your filling.

If your 41's radiator is the same as my 38's radiator, the overflow is well below the cap. Filling it to that will only guarantee loss of coolant as it expands. I fill my 38 to about an inch over the core.

Thanks for the fast answers. I feel better now that this was done right. I have the service manual but it does not indicate what side is up. And I am not trusting that the thing was put together correctly before I bought it since I have limited history on it.

Was there ever any type of overflow jar on these or was it just dump it as you drive? Our goal is a functional car to have fun with, not show condition car.

Yes, there was an overflow dealer installed option.

If an overflow container is mounted near the top of the radiator, and the end of the tube is below the level of the liquid in it, the radiator will refill itself from siphon action as the engine cools. That's how modern coolant reservoirs work, and you can scavenge one from a salvage yard that fits the space you have available.
Jerry