1994 Other Jaguar Models humid white smoke

Last year or 1500 miles ago, I had tons of white smoke coming out of the exhaust and the car was serviced for a head gasket and ran fine after that and 2500 dollars in repair. Now the check engine light is back on and, not as thick as before, but white humid smoke is coming out of the tail pipes and the engine is rising in temp to the point of overheating. Any ideas? Should the shop that performed the work warrenty me? Does it sound like it wasnt fixed properly?

George