I had a similar problem. Fluid would fill up my front crossmember and just sit there. While driving people would yell out the window hey you are leaking! My truck wasn't overheating so I was puzzled then I realized I had no overflow tank! So I bought one of those long skinny polished stainless overflow tubes for around $60. I had to cut/grind off the tube that exits the near the cap at the top of the radiator and I used some jb weld to hold in a new piece of metal tubing. Then I used vacuum hose to run down to the bottom of the new overflow tank.