The dealer's shop says we have a coolant leak coming from the Upper Bypass Gaskets/O-Rings which are located on the right side of the engine as you face the grill. It appears to be fairly involved to get to and requires the removal of the EGR valve and Water Passage in order to get to the connecting pipe with the offending O-ring. The leak appears to be a very small seeping of coolant that has left a small blue stain on the block. I couldn't find any wet coolant, just a little stain. $350 is the cost if they fix it. Is this something that is likely to become a gusher and strand my wife on the road or will it just continue to seep? Also, would it help to pour in some Stop Leak? I have avoided that stuff because I don't think it's smart enough to just plug the intended leak. Should I get it fixed right away or let it ride?