Hey ya'll, I'm a new member. Just bought a beautiful '99 Deville with 120,000 miles for 2 grand. Was previous owners mother's car. It is losing coolant, but not leaking. He replaced the radiator and the water pump. Runs and drives great, but will only go 6-7 miles before low coolant light comes on and you have to add water.Looks like head gasket problems. Took to local mechanic today, will see what he says. Can't decide whether to replace head gaskets and time -sert block or replace engine. If I replace engine, figured I'd go with the 9 code engine instead of the present Y code. Previously owned a '97 Deville Concours and she was great. Any thoughts?