Originally Posted by matts37chev
if you already tilted up the rad so the cap is even with the top (highest point)
if you put an overflow bottle on it like the truck rad had stock
it should alow air out, but will suck fluid in if it wants some
wait, did you leave it mounted up or out it back down?
Sorry, I was not clear on that, I tilted it up to fill the system and bleed out any air and then mounted it back down in the horizontal position. The system is running with an expansion tank and so far it appears to be venting and drawing coolant back in as needed.