Running hot after partial coolant change

Righty Tighty said

You know, maybe this explains why it was running warm after the rebuild. I added coolant prior to the first start and squeezed the upper radiator hose to assist in getting the coolant into all the nooks and crannies. Of course with a flat tappet cam, break in was pretty important, so I didn't even think of the coolant. Maybe there has always been air in the system?

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I use the theory that the 318 takes 4 full gallons of coolant to fill the block, heads and radiator. Don't forget the coolant that goes into the heater core too.

So if a person only gets 3 gallons of coolant in and the radiator is full, you know it is air locked yet.

So yeah, figure out a way to burp the air out of the intake manifold, then get the remainder of the 4 gallons of coolant into the cooling system.

Breaking in your cam on first start up and don't want to mess around with trying to burp air out while it is running. Leave the thermostat out for the 20 minute cam break in and the cooling system will easily fill up. Then after it cools down put your thermostat back in and make sure all of the coolant you just drained out goes back in to fill the system, then you know it is full.