Hay guys I need some ideas on what to do with my 69 cutlass. I've installed a 455 out of a 68 98 and I'm having a problem with the coolant, once it warms up it will dump 1/3 of the coolant out in to the over flow bottle. I'm running a 4 core radiator with a 160 thermostat and the temp gauge never gets over 170. I'm thinking there is an air bubble trapped in the system but I would like to hear your thoughts. This is my first Olds and I don't know if this is a common problem or not.

 

Have you tried a different radiator cap? It could be bad and letting the coolant out prematurely

 

Yep I have a new radiator cap.