Quote Originally Posted by Babyburr View Post
Explain what you mean by the right cap on radiator. Are you talking pressure or a small rubber hose coming off the neck where cap goes on?
The old style caps were made to burp out through the tube to the ground, but would suck air through the path of least resistance, as there was no seal between the cap and the top of the filler neck. Caps that are made to work with an overflow reservoir, where the radiator pukes through the tube, and then sucks back through the tube as the system cools and creates vacuum, have a gasket in the top to tightly seal the cap to the filler neck and pull down tight.