Get a block test done! That is the only way you will know if the car has blown a head gasket (which could have caused a cracked head), If you had a blown head gasket and the blown out part was big enough NO chemical will fix it. By the time you got the chemical in it you've already had fluids...
Lincoln and Mercury are owned by Ford which is the company that keeps the business I work for in business since Ford is the top most vehicles that we fix! Cadillac and Buick are again, basically the same car. I had an old Buick years ago and even with it being older then myself it was...