Technical SBC Overheat until thermostat opens. Help!

Air pockets in the cooling system is a real phenomenon, that in modern diesel engines with EGR coolers has become so problematic that filling the cooling systems via the radiator cap is no longer the prescribed method. The dealership service dept's are supposed to use a tool that draws coolant through the system using vacuum. Air pockets in EGR coolers has been determined to be the #1 cause of cooler failure, and we've seen a shit ton of EGR cooler failures. So yeah, this isn't just urban legend.

 

I forgot to mention if your worried about excessive hot or warm water bypassing the radiator if you use the bypass , they did sell a nipple that has a 3/8 restrictor hole in it , but I cannot seem to find them anymore , if you want the restriction you can use a 3/8" line and bush it down at the manifold and pump , the normal line is 5/8 " the block still has a bypass hole in them its the lower hole on the pump body on the pass side of the motor , but the manifold is still stagnant in flow and has to rely on thermal convection of the water

 

Well I opened it up the other night and drilled two 1/8 inch holes in the thermostat. I then filled it through the manifold before putting it back together. I started it in the garage and it slowly climbed to about 140. Today I drove it to a show and was the same! slow rise to about 160 and stated there while driving. So I think that drilling it solved the issue. Thanks everyone!