I suppose they made it flexible and replaceable because it seems to be in such a damage-prone location. The part only costs about $4. I can see where if it were forcefully pulled out that reseating properly might be a problem. the appropriate way to remove it is to get to the backside thru the radiator hose opening and slide a 10mm box wrench over the tangs, then pull up lightly. if it was yanked out, the flange on the radiator side tank may have been damaged, so even a new one might leak or pop out. In that case, only recourse would be a new side tank, or trying to epoxy it in (not a good approach I don't think.). I'd try a new one and see how it went in and if it felt secure before I tried glue.

DG