so i bought my first 7 on monday and a have been trying to track down a coolant problem

it has been pushing coolant into the overflow jug but not back into the radiator when it cools back down. i have been searching this forum and have stopped all vaccum leaks i can find in the overflow line (there may still be one in the overflow cap it has a small piece missing from the edge). the bottle gets so full that coolant squirts out of the breather hole

so anyway it was starting to look like the thermostat was in wrong or something but when we removed the cover there was no thermostat at all. would this also be causing the problems? also it has been losing coolant (about a gallon and a half) while trying to find the problem. but it has no visable leaks and no white smoke in exhaust when it warms up. i dont see how this much could have come of the overflow cap but i suppose its possible.

any help or input would be greatly appreciated

 

sorry cant find edit but it is a 86 gxl